New version of scsi code from Julian

1 files changed, 1498 insertions, 1941 deletions

diff --git a/sys/scsi/st.c b/sys/scsi/st.c
index e367389..08c8d467 100644
--- a/sys/scsi/st.c
+++ b/sys/scsi/st.c
@@ -12,13 +12,24 @@
  * on the understanding that TFS is not responsible for the correct
  * functioning of this software in any circumstances.
  *
+ *
+ * PATCHES MAGIC                LEVEL   PATCH THAT GOT US HERE
+ * --------------------         -----   ----------------------
+ * CURRENT PATCH LEVEL:         1       00098
+ * --------------------         -----   ----------------------
+ *
+ * 16 Feb 93    Julian Elischer         ADDED for SCSI system
+ * 1.15 is the last version to support MACH and OSF/1
+ */
+/* $Revision: 2.6 $ */
+
+/*
  * Ported to run under 386BSD by Julian Elischer (julian@tfs.com) Sept 1992
  * major changes by Julian Elischer (julian@jules.dialix.oz.au) May 1993
  *
- *	$Id: st.c,v 1.11 1993/10/16 17:21:10 rgrimes Exp $
+ *      $Id: st.c,v 2.6 93/10/21 03:24:38 julian Exp Locker: julian $
  */
 
-
 /*
  * To do:
  * work out some better way of guessing what a good timeout is going
@@ -41,886 +52,882 @@
 #include <sys/user.h>
 #include <sys/mtio.h>
 
-
 #include <scsi/scsi_all.h>
 #include <scsi/scsi_tape.h>
 #include <scsi/scsiconf.h>
 
-
-long int ststrats,stqueues;
+u_int32 ststrats, stqueues;
 
 /* Defines for device specific stuff */
 #define		PAGE_0_SENSE_DATA_SIZE	12
 #define PAGESIZ 	4096
 #define DEF_FIXED_BSIZE  512
-#define STQSIZE		4
-#define	ST_RETRIES	4
-
+#define	ST_RETRIES	4	/* only on non IO commands */
 
 #define MODE(z)		(  (minor(z)       & 0x03) )
 #define DSTY(z)         ( ((minor(z) >> 2) & 0x03) )
 #define UNIT(z)		(  (minor(z) >> 4) )
-
-#define DSTY3  3
-#define DSTY2  2
-#define DSTY1  1
+#define CTLMODE	3
 
 #define SCSI_2_MAX_DENSITY_CODE	0x17	/* maximum density code specified
-					   in SCSI II spec. */
-/***************************************************************\
-* Define various devices that we know mis-behave in some way,	*
-* and note how they are bad, so we can correct for them		*
-\***************************************************************/
-struct	modes
-{
-	int	quirks;		/* same definitions as in rogues */
-	char	density;
-	char	spare[3];
+					 * in SCSI II spec. */
+/*
+ * Define various devices that we know mis-behave in some way,
+ * and note how they are bad, so we can correct for them
+ */
+struct modes {
+	u_int32 blksiz;
+	u_int32 quirks;		/* same definitions as in rogues */
+	char    density;
+	char    spare[3];
 };
-struct	rogues
-{
-	char	*name;
-        char    *manu;
-        char    *model;
-        char    *version;
-	int	quirks;		/* valid for all modes */
-	struct	modes	modes[4];	
+
+struct rogues {
+	char   *name;
+	char   *manu;
+	char   *model;
+	char   *version;
+	u_int32 quirks;		/* valid for all modes */
+	struct modes modes[4];
 };
 
 /* define behaviour codes (quirks) */
 #define	ST_Q_NEEDS_PAGE_0	0x00001
 #define	ST_Q_FORCE_FIXED_MODE	0x00002
 #define	ST_Q_FORCE_VAR_MODE	0x00004
-#define	ST_Q_SNS_HLP		0x00008	/* must do READ for good MODE SENSE */
+#define	ST_Q_SNS_HLP		0x00008		/* must do READ for good MODE SENSE */
 #define	ST_Q_IGNORE_LOADS	0x00010
-#define	ST_Q_BLKSIZ		0x00020 /* variable-block media_blksiz > 0 */
+#define	ST_Q_BLKSIZ		0x00020		/* variable-block media_blksiz > 0 */
 
-static struct rogues gallery[] = /* ends with an all null entry */
+static struct rogues gallery[] =	/* ends with an all-null entry */
 {
-	{ "Such an old device ", "pre-scsi", " unknown model  ","????",
-		0,
-		{ {ST_Q_FORCE_FIXED_MODE,0},		/* minor  0,1,2,3 */
-		  {ST_Q_FORCE_FIXED_MODE,QIC_24},	/* minor  4,5,6,7 */
-		  {ST_Q_FORCE_VAR_MODE,HALFINCH_1600},	/* minor  8,9,10,11*/
-		  {ST_Q_FORCE_VAR_MODE,HALFINCH_6250}	/* minor  12,13,14,15*/
-		}
-	},
-	{ "Tandberg tdc3600", "TANDBERG", " TDC 3600","????",
-		ST_Q_NEEDS_PAGE_0,
-		{ {0,0},				/* minor  0,1,2,3*/
-		  {ST_Q_FORCE_VAR_MODE,QIC_525},	/* minor  4,5,6,7*/
-		  {0,QIC_150},				/* minor  8,9,10,11*/
-		  {0,QIC_120}				/* minor  12,13,14,15*/
-		}
-	},
-	{ "Rev 5 of the Archive 2525", "ARCHIVE ", "VIPER 2525 25462","-005",
-		0,
-		{ {ST_Q_SNS_HLP,0},			/* minor  0,1,2,3*/
-		  {ST_Q_SNS_HLP,QIC_525},		/* minor  4,5,6,7*/
-		  {0,QIC_150},				/* minor  8,9,10,11*/
-		  {0,QIC_120}				/* minor  12,13,14,15*/
-		}
-	},
-	{ "Archive  Viper 150", "ARCHIVE ", "VIPER 150","????",
-		ST_Q_NEEDS_PAGE_0,
-		{ {0,0},				/* minor  0,1,2,3*/
-		  {0,QIC_150},				/* minor  4,5,6,7*/
-		  {0,QIC_120},				/* minor  8,9,10,11*/
-		  {0,QIC_24}				/* minor  12,13,14,15*/
-		}
-	},
-	{ "Wangtek 5525ES", "WANGTEK ", "5525ES SCSI REV7", "????",
-		0,
-		{ {0,0},				/* minor  0,1,2,3*/
-		  {ST_Q_BLKSIZ,QIC_525},		/* minor  4,5,6,7*/
-		  {0,QIC_150},				/* minor  8,9,10,11*/
-		  {0,QIC_120}				/* minor  12,13,14,15*/
-		}
-	},
-	{(char *)0}
+    {"Such an old device ", "pre-scsi", " unknown model  ", "????",
+	0,
+	{
+	    {512, ST_Q_FORCE_FIXED_MODE, 0},	/* minor  0,1,2,3 */
+	    {512, ST_Q_FORCE_FIXED_MODE, QIC_24},	/* minor  4,5,6,7 */
+	    {0, ST_Q_FORCE_VAR_MODE, HALFINCH_1600},	/* minor  8,9,10,11 */
+	    {0, ST_Q_FORCE_VAR_MODE, HALFINCH_6250}	/* minor  12,13,14,15 */
+	}
+    },
+    {"Tandberg tdc3600", "TANDBERG", " TDC 3600", "????",
+	ST_Q_NEEDS_PAGE_0,
+	{
+	    {0, 0, 0},		/* minor  0,1,2,3 */
+	    {0, ST_Q_FORCE_VAR_MODE, QIC_525},	/* minor  4,5,6,7 */
+	    {0, 0, QIC_150},	/* minor  8,9,10,11 */
+	    {0, 0, QIC_120}	/* minor  12,13,14,15 */
+	}
+    },
+    {"Rev 5 of the Archive 2525", "ARCHIVE ", "VIPER 2525 25462", "-005",
+	0,
+	{
+	    {0, ST_Q_SNS_HLP, 0},	/* minor  0,1,2,3 */
+	    {0, ST_Q_SNS_HLP, QIC_525},		/* minor  4,5,6,7 */
+	    {0, 0, QIC_150},	/* minor  8,9,10,11 */
+	    {0, 0, QIC_120}	/* minor  12,13,14,15 */
+	}
+    },
+    {"Archive  Viper 150", "ARCHIVE ", "VIPER 150", "????",
+	ST_Q_NEEDS_PAGE_0,
+	{
+	    {0, 0, 0},		/* minor  0,1,2,3 */
+	    {0, 0, QIC_150},	/* minor  4,5,6,7 */
+	    {0, 0, QIC_120},	/* minor  8,9,10,11 */
+	    {0, 0, QIC_24}	/* minor  12,13,14,15 */
+	}
+    },
+    {"Wangtek 5525ES", "WANGTEK ", "5525ES SCSI REV7", "????",
+	0,
+	{
+	    {0, 0, 0},		/* minor  0,1,2,3 */
+	    {0, ST_Q_BLKSIZ, QIC_525},	/* minor  4,5,6,7 */
+	    {0, 0, QIC_150},	/* minor  8,9,10,11 */
+	    {0, 0, QIC_120}	/* minor  12,13,14,15 */
+	}
+    },
+    {"WangDAT model 1300", "WangDAT ", "Model 1300", "????",
+	0,
+	{
+	    {0, 0, 0},					/* minor  0,1,2,3 */
+	    {512, ST_Q_FORCE_FIXED_MODE, 0x13},		/* minor  4,5,6,7 */
+	    {1024, ST_Q_FORCE_FIXED_MODE, 0x13},	/* minor  8,9,10,11 */
+	    {0, ST_Q_FORCE_VAR_MODE, 0x13}		/* minor  12,13,14,15 */
+	}
+    },
+    {(char *) 0}
 };
 
-
-int	ststrategy();
-void	stminphys();
+errval	st_space __P((u_int32 unit, int32 number, u_int32 what, u_int32 flags));
+errval	st_rewind __P((u_int32 unit, boolean immed, u_int32 flags));
+errval	st_mode_sense __P((u_int32 unit, u_int32 flags));
+errval	st_decide_mode __P((u_int32 unit, boolean first_read));
+errval	st_rd_blk_lim __P((u_int32 unit, u_int32 flags));
+errval	st_touch_tape __P((u_int32 unit));
+errval	st_write_filemarks __P((u_int32 unit, int32 number, u_int32 flags));
+errval	st_load __P((u_int32 unit, u_int32 type, u_int32 flags));
+errval	st_mode_select __P((u_int32 unit, u_int32 flags));
+void    ststrategy();
+void    stminphys();
+int32   st_chkeod();
+errval  stattach();
+void    ststart();
+void	st_unmount();
+errval	st_mount_tape();
+void	st_loadquirks();
+void	st_identify_drive();
+errval  st_interpret_sense();
 
 #define ESUCCESS 0
+#define NOEJECT 0
+#define EJECT 1
 
-#ifdef	STDEBUG
-int	st_debug = 1;
-#endif	/*STDEBUG*/
-
-int stattach();
-int st_done();
-
-struct	st_data
+struct scsi_device st_switch =
 {
+    st_interpret_sense,		/* check errors with us first */
+    ststart,			/* we have a queue, and this is how we service it */
+    NULL,
+    NULL,			/* use the default 'done' routine */
+    "st",
+    0,
+    { 0, 0 }
+};
+
+struct st_data {
 /*--------------------present operating parameters, flags etc.----------------*/
-	int	flags;			/* see below 			      */
-	int	blksiz;			/* blksiz we are using		      */
-	int	density;		/* present density 		      */
-	int	quirks;			/* quirks for the open mode	      */
-	int	last_dsty;		/* last density used		      */
+	u_int32 flags;		/* see below                          */
+	u_int32 blksiz;		/* blksiz we are using                */
+	u_int32 density;	/* present density                    */
+	u_int32 quirks;		/* quirks for the open mode           */
+	u_int32 last_dsty;	/* last density openned               */
 /*--------------------device/scsi parameters----------------------------------*/
-	struct	scsi_switch *sc_sw;	/* address of scsi low level switch   */
-	int	ctlr;			/* so they know which one we want     */
-	int	targ;			/* our scsi target ID 		      */
-	int	lu;			/* our scsi lu 			      */
+	struct scsi_link *sc_link;	/* our link to the adpter etc.        */
 /*--------------------parameters reported by the device ----------------------*/
-	int	blkmin;			/* min blk size 		      */
-	int	blkmax;			/* max blk size 		      */
+	u_int32 blkmin;		/* min blk size                       */
+	u_int32 blkmax;		/* max blk size                       */
+	struct rogues *rogues;	/* if we have a rogue entry           */
 /*--------------------parameters reported by the device for this media--------*/
-	int	numblks;		/* nominal blocks capacity 	      */
-	int	media_blksiz;		/* 0 if not ST_FIXEDBLOCKS 	      */
-	int	media_density;		/* this is what it said when asked    */
+	u_int32 numblks;	/* nominal blocks capacity            */
+	u_int32 media_blksiz;	/* 0 if not ST_FIXEDBLOCKS            */
+	u_int32 media_density;	/* this is what it said when asked    */
 /*--------------------quirks for the whole drive------------------------------*/
-	int	drive_quirks;		/* quirks of this drive		      */
+	u_int32 drive_quirks;	/* quirks of this drive               */
 /*--------------------How we should set up when openning each minor device----*/
-	struct	modes	modes[4];	/* plus more for each mode 	      */
+	struct modes modes[4];	/* plus more for each mode            */
+	u_int8  modeflags[4];	/* flags for the modes                */
+#define DENSITY_SET_BY_USER	0x01
+#define DENSITY_SET_BY_QUIRK	0x02
+#define BLKSIZE_SET_BY_USER	0x04
+#define BLKSIZE_SET_BY_QUIRK	0x08
 /*--------------------storage for sense data returned by the drive------------*/
-        unsigned char   sense_data[12]; /* additional sense data needed       */
-                                        /* for mode sense/select. 	      */
-	struct	buf *buf_queue;		/* the queue of pending IO operations */
-	struct	scsi_xfer scsi_xfer;	/* The scsi xfer struct for this drive*/
-	int	xfer_block_wait;	/* whether there is a process waiting */
-}*st_data[NST];
+	unsigned char sense_data[12];	/*
+					 * additional sense data needed
+					 * for mode sense/select.
+					 */
+	struct buf *buf_queue;		/* the queue of pending IO operations */
+	struct scsi_xfer scsi_xfer;	/* scsi xfer struct for this drive */
+	u_int32 xfer_block_wait;	/* is a process waiting? */
+}      *st_data[NST];
+
 #define ST_INITIALIZED	0x01
 #define	ST_INFO_VALID	0x02
 #define ST_OPEN		0x04
-#define	ST_BLOCK_SET	0x08		/* block size, mode set by ioctl      */
-#define	ST_WRITTEN	0x10		/* data have been written, EOD needed */
+#define	ST_BLOCK_SET	0x08	/* block size, mode set by ioctl      */
+#define	ST_WRITTEN	0x10	/* data have been written, EOD needed */
 #define	ST_FIXEDBLOCKS	0x20
 #define	ST_AT_FILEMARK	0x40
-#define	ST_EIO_PENDING	0x80		/* we couldn't report it then (had data)*/
-#define	ST_AT_BOM	0x100		/* ops history suggests Beg of Medium */
-#define	ST_READONLY	0x200		/* st_mode_sense says write protected */
-#define	ST_FM_WRITTEN	0x400		/* EOF file mark written  -- */
-					/* used with ~ST_WRITTEN to indicate  */
-					/* that multiple file marks have been */
-					/* written			      */
-#define	ST_BLANK_READ	0x800		/* BLANK CHECK encountered already */
-#define	ST_2FM_AT_EOD	0x1000		/* write 2 file marks at EOD */
+#define	ST_EIO_PENDING	0x80	/* we couldn't report it then (had data) */
+#define	ST_NEW_MOUNT	0x100	/* still need to decide mode              */
+#define	ST_READONLY	0x200	/* st_mode_sense says write protected */
+#define	ST_FM_WRITTEN	0x400	/*
+				 * EOF file mark written  -- used with
+				 * ~ST_WRITTEN to indicate that multiple file
+				 * marks have been written
+				 */
+#define	ST_BLANK_READ	0x800	/* BLANK CHECK encountered already */
+#define	ST_2FM_AT_EOD	0x1000	/* write 2 file marks at EOD */
+#define	ST_MOUNTED	0x2000	/* Device is presently mounted */
 
 #define	ST_PER_ACTION	(ST_AT_FILEMARK | ST_EIO_PENDING | ST_BLANK_READ)
-#define	ST_PER_OPEN	ST_OPEN
-#define	ST_PER_MEDIA	(ST_INFO_VALID | ST_BLOCK_SET | ST_WRITTEN | \
-			ST_FIXEDBLOCKS | ST_AT_BOM | ST_READONLY | \
+#define	ST_PER_MOUNT	(ST_INFO_VALID | ST_BLOCK_SET | ST_WRITTEN | \
+			ST_FIXEDBLOCKS | ST_READONLY | \
 			ST_FM_WRITTEN | ST_2FM_AT_EOD | ST_PER_ACTION)
 
-static	int	next_st_unit = 0;
-/***********************************************************************\
-* The routine called by the low level scsi routine when it discovers	*
-* A device suitable for this driver					*
-\***********************************************************************/
+static u_int32 next_st_unit = 0;
 
-int	stattach(ctlr,targ,lu,scsi_switch)
-struct	scsi_switch *scsi_switch;
+/*
+ * The routine called by the low level scsi routine when it discovers
+ * A device suitable for this driver
+ */
+
+errval 
+stattach(sc_link)
+	struct scsi_link *sc_link;
 {
-	int	unit,i;
+	u_int32 unit;
 	struct st_data *st;
 
-#ifdef	STDEBUG
-	if(scsi_debug & PRINTROUTINES) printf("stattach: ");
-#endif	/*STDEBUG*/
-	/*******************************************************\
-	* Check we have the resources for another drive		*
-	\*******************************************************/
+	SC_DEBUG(sc_link, SDEV_DB2, ("stattach: "));
+	/*
+	 * Check we have the resources for another drive
+	 */
 	unit = next_st_unit++;
-	if( unit >= NST)
-	{
+
+	if (unit >= NST) {
 		printf("Too many scsi tapes..(%d > %d) reconfigure kernel\n",
-				(unit + 1),NST);
-		return(0);
+		    (unit + 1), NST);
+		return 0;
 	}
-	if(st_data[unit])
-	{
-		printf("st%d: Already has storage!\n",unit);
-		return(0);
+	if (st_data[unit]) {
+		printf("st%d: Already has storage!\n", unit);
+		return 0;
 	}
-	st = st_data[unit] = malloc(sizeof(struct st_data),M_DEVBUF,M_NOWAIT);
-	if(!st)
-	{
-		printf("st%d: malloc failed in st.c\n",unit);
-		return(0);
+	sc_link->device = &st_switch;
+	sc_link->dev_unit = unit;
+	st = st_data[unit] = malloc(sizeof(struct st_data), M_DEVBUF, M_NOWAIT);
+	if (!st) {
+		printf("st%d: malloc failed in st.c\n", unit);
+		return 0;
 	}
-	bzero(st,sizeof(struct st_data));
-
-	/*******************************************************\
-	* Store information needed to contact our base driver	*
-	\*******************************************************/
-	st->sc_sw	=	scsi_switch;
-	st->ctlr	=	ctlr;
-	st->targ	=	targ;
-	st->lu		=	lu;
-
-	/*******************************************************\
-	* Store information about default densities 		*
-	\*******************************************************/
-	st->modes[DSTY1].density	=	QIC_525;
-	st->modes[DSTY2].density	=	QIC_150;
-	st->modes[DSTY3].density	=	QIC_120;
-
-	/*******************************************************\
-	* Check if the drive is a known criminal and take	*
-	* Any steps needed to bring it into line		*
-	\*******************************************************/
+	bzero(st, sizeof(struct st_data));
+
+	/*
+	 * Store information needed to contact our base driver
+	 */
+	st->sc_link = sc_link;
+
+	/*
+	 * Check if the drive is a known criminal and take
+	 * Any steps needed to bring it into line
+	 */
 	st_identify_drive(unit);
 
-	/*******************************************************\
-	* Use the subdriver to request information regarding	*
-	* the drive. We cannot use interrupts yet, so the	*
-	* request must specify this.				*
-	\*******************************************************/
-	if(st_mode_sense(unit, SCSI_NOSLEEP |  SCSI_NOMASK | SCSI_SILENT))
-	{
+	/*
+	 * Use the subdriver to request information regarding
+	 * the drive. We cannot use interrupts yet, so the
+	 * request must specify this.
+	 */
+	if (st_mode_sense(unit, SCSI_NOSLEEP | SCSI_NOMASK | SCSI_SILENT)) {
 		printf("st%d: drive offline\n", unit);
-	}
-	else
-	{
-		if(!st_test_ready(unit,SCSI_NOSLEEP | SCSI_NOMASK | SCSI_SILENT))
-		{
-			printf("st%d: density code 0x%x, ",
-			    unit, st->media_density);
-			if (st->media_blksiz)
-			{
+	} else {
+		printf("st%d: density code 0x%x, ", unit, st->media_density);
+		if (!scsi_test_unit_ready(sc_link, SCSI_NOSLEEP | SCSI_NOMASK | SCSI_SILENT)) {
+			if (st->media_blksiz) {
 				printf("%d-byte", st->media_blksiz);
-			}
-			else
-			{
+			} else {
 				printf("variable");
 			}
 			printf(" blocks, write-%s\n",
-			    st->flags & ST_READONLY ? "protected" : "enabled");
-		}
-		else
-		{
-			printf("st%d: drive empty\n", unit);
+			    (st->flags & ST_READONLY) ? "protected" : "enabled");
+		} else {
+			printf(" drive empty\n");
 		}
 	}
-	/*******************************************************\
-	* Set up the bufs for this device			*
-	\*******************************************************/
-	st->buf_queue	=	0;
-
-
+	/*
+	 * Set up the buf queue for this device
+	 */
+	st->buf_queue = 0;
 	st->flags |= ST_INITIALIZED;
-	return;
-
+	return 0;
 }
 
-/***********************************************************************\
-* Use the identify routine in 'scsiconf' to get drive info so we can	*
-* Further tailor our behaviour.						*
-\***********************************************************************/
-
+/*
+ * Use the inquiry routine in 'scsi_base' to get drive info so we can
+ * Further tailor our behaviour.
+ */
+void
 st_identify_drive(unit)
-int	unit;
+	u_int32 unit;
 {
-
-	struct	st_data *st = st_data[unit];
-	struct scsi_inquiry_data        inqbuf;
-	struct	rogues *finger;
-        char    manu[32];
-        char    model[32];
-        char    model2[32];
-        char    version[32];
-	int	model_len;
-
-
-	/*******************************************************\
-	* Get the device type information                       *
-	\*******************************************************/
-	if (scsi_inquire(st->ctlr, st->targ, st->lu, st->sc_sw, &inqbuf,
-		SCSI_NOSLEEP | SCSI_NOMASK | SCSI_SILENT) != COMPLETE)
-	{
+	struct st_data *st = st_data[unit];
+	struct scsi_inquiry_data inqbuf;
+	struct rogues *finger;
+	char    manu[32];
+	char    model[32];
+	char    model2[32];
+	char    version[32];
+	u_int32 model_len;
+
+	/*
+	 * Get the device type information
+	 */
+	if (scsi_inquire(st->sc_link, &inqbuf,
+		SCSI_NOSLEEP | SCSI_NOMASK | SCSI_SILENT) != 0) {
 		printf("st%d: couldn't get device type, using default\n", unit);
 		return;
 	}
-	if((inqbuf.version & SID_ANSII) == 0)
-	{
-		/***********************************************\
-		* If not advanced enough, use default values    *
-		\***********************************************/
-		strncpy(manu,"pre-scsi",8);manu[8]=0;
-		strncpy(model," unknown model  ",16);model[16]=0;
-		strncpy(version,"????",4);version[4]=0;
+	if ((inqbuf.version & SID_ANSII) == 0) {
+		/*
+		 * If not advanced enough, use default values
+		 */
+		strncpy(manu, "pre-scsi", 8);
+		manu[8] = 0;
+		strncpy(model, " unknown model  ", 16);
+		model[16] = 0;
+		strncpy(version, "????", 4);
+		version[4] = 0;
+	} else {
+		strncpy(manu, inqbuf.vendor, 8);
+		manu[8] = 0;
+		strncpy(model, inqbuf.product, 16);
+		model[16] = 0;
+		strncpy(version, inqbuf.revision, 4);
+		version[4] = 0;
 	}
-	else
-	{
-		strncpy(manu,inqbuf.vendor,8);manu[8]=0;
-		strncpy(model,inqbuf.product,16);model[16]=0;
-		strncpy(version,inqbuf.revision,4);version[4]=0;
-	}
-	 
-	/*******************************************************\
-	* Load the parameters for this kind of device, so we	*
-	* treat it as appropriate for each operating mode 	*
-	* Only check the number of characters in the array's	*
-	* model entry, not the entire model string returned.	*
-	\*******************************************************/
+
+	/*
+	 * Load the parameters for this kind of device, so we
+	 * treat it as appropriate for each operating mode.
+	 * Only check the number of characters in the array's
+	 * model entry, not the entire model string returned.
+	 */
 	finger = gallery;
-	while(finger->name)
-	{
+	while (finger->name) {
 		model_len = 0;
-		while(finger->model[model_len] && (model_len < 32))
-		{
+		while (finger->model[model_len] && (model_len < 32)) {
 			model2[model_len] = model[model_len];
 			model_len++;
 		}
 		model2[model_len] = 0;
-		if ((strcmp(manu, finger->manu) == 0 )
-			&& (strcmp(model2, finger->model) == 0 ||
-			   strcmp("????????????????", finger->model) == 0)
-			&& (strcmp(version, finger->version) == 0 ||
-			   strcmp("????", finger->version) == 0))
-		{
-			printf("st%d: %s is a known rogue\n", unit,finger->name);
-			st->modes[0]	=	finger->modes[0];
-			st->modes[1]	=	finger->modes[1];
-			st->modes[2]	=	finger->modes[2];
-			st->modes[3]	=	finger->modes[3];
-			st->drive_quirks=	finger->quirks;
-			st->quirks	=	finger->quirks; /*start value*/
+		if ((strcmp(manu, finger->manu) == 0)
+		    && (strcmp(model2, finger->model) == 0 ||
+			strcmp("????????????????", finger->model) == 0)
+		    && (strcmp(version, finger->version) == 0 ||
+			strcmp("????", finger->version) == 0)) {
+			printf("st%d: %s is a known rogue\n", unit, finger->name);
+			st->rogues = finger;
+			st->drive_quirks = finger->quirks;
+			st->quirks = finger->quirks;	/*start value */
+			st_loadquirks(st);
 			break;
-		}
-		else
-		{
+		} else {
 			finger++;	/* go to next suspect */
 		}
 	}
 }
 
-/*******************************************************\
-*	open the device.				*
-\*******************************************************/
+/*
+ * initialise the subdevices to the default (QUIRK) state.
+ * this will remove any setting made by the system operator or previous
+ * operations.
+ */
+void
+st_loadquirks(st)
+	struct st_data *st;
+{
+	int     i;
+	struct	modes *mode;
+	struct	modes *mode2;
+
+	if (!st->rogues)
+		return;
+	mode = st->rogues->modes;
+	mode2 = st->modes;
+	for (i = 0; i < 4; i++) {
+		bzero(mode2, sizeof(struct modes));
+		st->modeflags[i] &= ~(BLKSIZE_SET_BY_QUIRK
+		    | DENSITY_SET_BY_QUIRK
+		    | BLKSIZE_SET_BY_USER
+		    | DENSITY_SET_BY_USER);
+		if (mode->blksiz && ((mode->quirks | st->drive_quirks)
+			& (ST_Q_FORCE_FIXED_MODE))) {
+			mode2->blksiz = mode->blksiz;
+			st->modeflags[i] |= BLKSIZE_SET_BY_QUIRK;
+		} else {
+			if ((mode->quirks | st->drive_quirks)
+			    & ST_Q_FORCE_VAR_MODE) {
+				mode2->blksiz = 0;
+				st->modeflags[i] |= BLKSIZE_SET_BY_QUIRK;
+			}
+		}
+		if (mode->density) {
+			mode2->density = mode->density;
+			st->modeflags[i] |= DENSITY_SET_BY_QUIRK;
+		}
+		mode++;
+		mode2++;
+	}
+}
+
+/*
+ * open the device.
+ */
+errval 
 stopen(dev, flags)
-int	dev, flags;
+	dev_t   dev;
+	u_int32 flags;
 {
-	int unit,mode,dsty;
-	int	errno = 0;
+	u_int32 unit, mode, dsty;
+	errval  errno = 0;
 	struct st_data *st;
+	struct scsi_link *sc_link;
 	unit = UNIT(dev);
 	mode = MODE(dev);
 	dsty = DSTY(dev);
 
-	/*******************************************************\
-	* Check the unit is legal                               *
-	\*******************************************************/
-	if ( unit >= NST )
-	{
-		return(ENXIO);
+	/*
+	 * Check the unit is legal
+	 */
+	if (unit >= NST) {
+		return (ENXIO);
 	}
 	st = st_data[unit];
-	/*******************************************************\
-	* Make sure the device has been initialised		*
-	\*******************************************************/
+	/*
+	 * Make sure the device has been initialised
+	 */
 	if ((st == NULL) || (!(st->flags & ST_INITIALIZED)))
-		return(ENXIO);
-
-	/*******************************************************\
-	* Only allow one at a time				*
-	\*******************************************************/
-	if(st->flags & ST_OPEN)
-	{
-		return(ENXIO);
+		return (ENXIO);
+
+	sc_link = st->sc_link;
+	SC_DEBUG(sc_link, SDEV_DB1, ("open: dev=0x%x (unit %d (of %d))\n"
+		,dev, unit, NST));
+	/*
+	 * Only allow one at a time
+	 */
+	if (st->flags & ST_OPEN) {
+		return (ENXIO);
 	}
-
-	/*******************************************************\
-	* Throw out a dummy instruction to catch 'Unit attention*
-	* errors (the error handling will invalidate all our	*
-	* device info if we get one, but otherwise, ignore it	*
-	\*******************************************************/
-	st_test_ready(unit, SCSI_SILENT); 
-
-	/***************************************************************\
-	* Check that the device is ready to use	 (media loaded?)	*
-	* This time take notice of the return result			*
-	\***************************************************************/
-	if(errno = (st_test_ready(unit,0))) 
-	{
-		printf("st%d: not ready\n",unit);
-		return(errno);
+	/*
+	 * Throw out a dummy instruction to catch 'Unit attention
+	 * errors (the error handling will invalidate all our
+	 * device info if we get one, but otherwise, ignore it)
+	 */
+	scsi_test_unit_ready(sc_link, SCSI_SILENT);
+
+	sc_link->flags |= SDEV_OPEN;	/* unit attn are now errors */
+	/*
+	 * If the mode is 3 (e.g. minor = 3,7,11,15)
+	 * then the device has been openned to set defaults
+	 * This mode does NOT ALLOW I/O, only ioctls
+	 */
+	if (mode == CTLMODE)
+		return 0;
+
+	/*
+	 * Check that the device is ready to use (media loaded?)
+	 * This time take notice of the return result
+	 */
+	if (errno = (scsi_test_unit_ready(sc_link, 0))) {
+		printf("st%d: not ready\n", unit);
+		st_unmount(unit, NOEJECT);
+		return (errno);
 	}
-
-	/*******************************************************\
-	* Set up the mode flags according to the minor number	*
-	* ensure all open flags are in a known state		*
-	* if it's a different mode, dump all cached parameters	*
-	\*******************************************************/
-	if(st->last_dsty != dsty || !(st->flags & ST_INFO_VALID))
-	{
-		st->flags &= ~ST_INFO_VALID;
-		st->last_dsty = dsty;
-		st->quirks = st->drive_quirks | st->modes[dsty].quirks;
-		st->density = st->modes[dsty].density;
+	/*
+	 * if it's a different mode, or if the media has been
+	 * invalidated, unmount the tape from the previous
+	 * session but continue with open processing
+	 */
+	if ((st->last_dsty != dsty)
+	    || (!(sc_link->flags & SDEV_MEDIA_LOADED))) {
+		st_unmount(unit, NOEJECT);
 	}
-	st->flags &= ~ST_PER_OPEN;
-
-#ifdef	STDEBUG
-	if(scsi_debug & (PRINTROUTINES | TRACEOPENS))
-		printf("stopen: dev=0x%x (unit %d (of %d))\n"
-				,   dev,      unit,   NST);
-#endif	/*STDEBUG*/
-	/***************************************************************\
-	* If the media is new, then make sure we give it a chance to	*
-	* to do a 'load' instruction.					*
-	\***************************************************************/
-	if(!(st->flags & ST_INFO_VALID))		/* is media new? */
-	{
-		if(errno = st_load(unit,LD_LOAD,0))
-		{
-			return(errno);
-		}
-		st_test_ready(unit,0);
-		if(st->quirks & ST_Q_SNS_HLP)
-		{
-			/***********************************************\
-			* The quirk here is that the drive returns some	*
-			* value to st_mode_sense incorrectly until the	*
-			* tape has actually passed by the head.		*
-			*						*
-			* The method is to set the drive to large	*
-			* fixed-block state (user-specified density and	*
-			* 1024-byte blocks), then read and rewind to	*
-			* get it to sense the tape.  If that doesn't	*
-			* work, try 512-byte fixed blocks.  If that	*
-			* doesn't work, as a last resort, try variable-	*
-			* length blocks.  The result will be the	*
-			* ability to do an accurate st_mode_sense.	*
-			*						*
-			* We pretend not to be at beginning of medium	*
-			* to keep st_read from calling st_decide_mode.	*
-			*						*
-			* We know we can do a rewind because we just	*
-			* did a load, which implies rewind.  Rewind	*
-			* seems preferable to space backward if	we have	*
-			* a virgin tape.				*
-			*						*
-			* The rest of the code for this quirk is in ILI	*
-			* processing and BLANK CHECK error processing,	*
-			* both part of st_interpret_sense.		*
-			\***********************************************/
-			char	*buf;
-			int	readsiz;
-
-			buf = malloc(1024,M_TEMP,M_NOWAIT);
-			if(!buf) return(ENOMEM);
-
-			if (errno = st_mode_sense(unit, 0))
-			{
-				goto bad;
-			}
-			st->blksiz = 1024;
-			do {
-				switch (st->blksiz)
-				{
-				case	512:
-				case	1024:
-					readsiz = st->blksiz;
-					st->flags |= ST_FIXEDBLOCKS;
-					break;
-				default:
-					readsiz = 1;
-					st->flags &= ~ST_FIXEDBLOCKS;
-				}
-				if (errno = st_mode_select(unit, 0))
-				{
-					goto bad;
-				}
-				st->flags &= ~ST_AT_BOM;
-				st_read(unit, buf, readsiz, SCSI_SILENT);
-				if (errno = st_rewind(unit, FALSE, 0))
-				{
-bad:					free(buf,M_TEMP);
-					return(errno);
-				}
-			} while (readsiz != 1 && readsiz > st->blksiz);
-			free(buf,M_TEMP);
-		}
-	}
-
-	/*******************************************************\
-	* Load the physical device parameters			*
-	* loads: blkmin, blkmax					*
-	\*******************************************************/
-	if(errno = st_rd_blk_lim(unit,0))
-	{
-		return(errno);
-	}
-
-	/*******************************************************\
-	* Load the media dependent parameters			*
-	* includes: media_blksiz,media_density,numblks		*
-	\*******************************************************/
-	if(errno = st_mode_sense(unit,0))
-	{
-		return(errno);
-	}
-
-	if (!(st->flags & ST_INFO_VALID) && dsty == 0)
-	{
-		/*******************************************************\
-		* If the user defaulted the density, use the drive's	*
-		* opinion of it.					*
-		\*******************************************************/
-		st->quirks = st->drive_quirks;
-		st->density = st->media_density;
-		do {
-			if (st->density == st->modes[dsty].density)
-			{
-				st->quirks |= st->modes[dsty].quirks;
-#ifdef	STDEBUG
-				if(st_debug) printf("selected density %d\n", dsty);
-#endif	/*STDEBUG*/
-				break; /* only out of the loop*/
-			}
-		} while (++dsty < 4);
-		/*******************************************************\
-		* If dsty got to 4, the drive must have reported a	*
-		* density which isn't in our density list (e.g. QIC-24	*
-		* for a default drive).  We can handle that, except	*
-		* there'd better be no density-specific quirks in the	*
-		* drive's behavior.					*
-		\*******************************************************/
-	}
-
-	/***************************************************************\
-	* Decide whether or not to write two file marks to signify end-	*
-	* of-data.  Make the decision as a function of density.  If	*
-	* the decision is not to use a second file mark, the SCSI BLANK	*
-	* CHECK condition code will be recognized as end-of-data when	*
-	* first read.							*
-	\***************************************************************/
-	switch (st->density)
-	{
-/*	case	8 mm:	What is the SCSI density code for 8 mm, anyway? */
-	case	QIC_11:
-	case	QIC_24:
-	case	QIC_120:
-	case	QIC_150:
-	case	QIC_525:
-	case	QIC_1320:
-		st->flags &= ~ST_2FM_AT_EOD;
-		break;
-	default:
-		st->flags |= ST_2FM_AT_EOD;
+	/*
+	 * If we are not mounted, then we should start a new 
+	 * mount session.
+	 */
+	if (!(st->flags & ST_MOUNTED)) {
+		st_mount_tape(dev, flags);
+		st->last_dsty = dsty;
 	}
-
-	/***************************************************************\
-	* Make sure that a tape opened in write-only mode will have	*
-	* file marks written on it.  This is the only way to write a	*
-	* zero-length file on tape.					*
-	\***************************************************************/
+	/*
+	 * Make sure that a tape opened in write-only mode will have
+	 * file marks written on it when closed, even if not written to.
+	 * This is for SUN compatibility
+	 */
 	if ((flags & O_ACCMODE) == FWRITE)
 		st->flags |= ST_WRITTEN;
 
-	st->flags |= ST_INFO_VALID;
-
-	st_prevent(unit,PR_PREVENT,0); /* who cares if it fails? */
-
-#ifdef	STDEBUG
-	if(scsi_debug & TRACEOPENS)
-		printf("Params loaded ");
-#endif	/*STDEBUG*/
+	SC_DEBUG(sc_link, SDEV_DB2, ("Open complete\n"));
 
 	st->flags |= ST_OPEN;
-	return(0);
+	return (0);
 }
 
-/*******************************************************\
-* close the device.. only called if we are the LAST	*
-* occurence of an open device				*
-\*******************************************************/
+/*
+ * close the device.. only called if we are the LAST
+ * occurence of an open device
+ */
+errval 
 stclose(dev)
+	dev_t   dev;
 {
-	unsigned char unit,mode;
-	struct	st_data *st;
+	unsigned char unit, mode;
+	struct st_data *st;
+	struct scsi_link *sc_link;
 
 	unit = UNIT(dev);
 	mode = MODE(dev);
 	st = st_data[unit];
-
-#ifdef	STDEBUG
-	if(scsi_debug & TRACEOPENS)
-		printf("Closing device");
-#endif	/*STDEBUG*/
-	switch(mode)
-	{
-	case	0:
-		st_rewind(unit,FALSE,SCSI_SILENT);
-		st_prevent(unit,PR_ALLOW,SCSI_SILENT);
-		st->flags &= ~ST_PER_MEDIA;
-		break;
-	case	1: /*non rewind*/
-		if((st->flags & (ST_WRITTEN | ST_FM_WRITTEN)) == ST_WRITTEN)
-			st_write_filemarks(unit, 1, 0);
+	sc_link = st->sc_link;
+
+	SC_DEBUG(sc_link, SDEV_DB1, ("closing\n"));
+	if ((st->flags & (ST_WRITTEN | ST_FM_WRITTEN)) == ST_WRITTEN)
+		st_write_filemarks(unit, 1, 0);
+	switch (mode & 0x3) {
+	case 0:
+	case 3:		/* for now */
+		st_unmount(unit, NOEJECT);
 		break;
-	case	2:
-		st_rewind(unit,FALSE,SCSI_SILENT);
-		st_prevent(unit,PR_ALLOW,SCSI_SILENT);
-		st_load(unit,LD_UNLOAD,SCSI_SILENT);
-		st->flags &= ~ST_PER_MEDIA;
+	case 1:		/*leave mounted unless media seems to have been removed */
+		if (!(sc_link->flags & SDEV_MEDIA_LOADED)) {
+			st_unmount(unit, NOEJECT);
+		}
 		break;
-	case	3:/* a bit silly really */
-		st_prevent(unit,PR_ALLOW,SCSI_SILENT);
-		st_load(unit,LD_UNLOAD,SCSI_SILENT);
-		st->flags &= ~ST_PER_MEDIA;
+	case 2:
+		st_unmount(unit, EJECT);
 		break;
-	default:
-		printf("st%d: close: Bad mode (minor number)%d how's it open?\n"
-				,unit,mode);
-		return(EINVAL);
 	}
-	st->flags &= ~ST_PER_OPEN;
-	return(0);
+	sc_link->flags &= ~SDEV_OPEN;
+	st->flags &= ~ST_OPEN;
+	return (0);
 }
 
-/***************************************************************\
-* Given all we know about the device, media, mode, 'quirks' and	*
-* initial operation, make a decision as to how we should be set	*
-* up.  First, choose the density, then variable/fixed blocks.	*
-\***************************************************************/
-st_decide_mode(unit, first_read)
-int	unit, first_read;
+/*
+ * Start a new mount session.
+ * Copy in all the default parameters from the selected device mode.
+ * and try guess any that seem to be defaulted.
+ */
+errval
+st_mount_tape(dev, flags)
+	dev_t   dev;
+	u_int32 flags;
 {
-	int dsty, error;
-	struct st_data *st = st_data[unit];
+	u_int32 unit, mode, dsty;
+	struct st_data *st;
+	struct scsi_link *sc_link;
+	errval  errno = 0;
 
-	/***************************************************************\
-	* First, if our information about the tape is out of date, get	*
-	* new information.						*
-	\***************************************************************/
-	if (!(st->flags & ST_INFO_VALID))
-	{
-		if (error = st_mode_sense(unit, 0))
-			return (error);
-		st->flags |= ST_INFO_VALID;
+	unit = UNIT(dev);
+	mode = MODE(dev);
+	dsty = DSTY(dev);
+	st = st_data[unit];
+	sc_link = st->sc_link;
+
+	if (st->flags & ST_MOUNTED)
+		return 0;
+
+	SC_DEBUG(sc_link, SDEV_DB1, ("mounting\n "));
+	st->flags |= ST_NEW_MOUNT;
+	st->quirks = st->drive_quirks | st->modes[dsty].quirks;
+	/*
+	 * If the media is new, then make sure we give it a chance to
+	 * to do a 'load' instruction. ( We assume it is new)
+	 */
+	if (errno = st_load(unit, LD_LOAD, 0)) {
+		return (errno);
 	}
-#ifdef	STDEBUG
-	if(st_debug) printf("starting mode decision\n");
-#endif	/*STDEBUG*/
-
-	/***************************************************************\
-	* If the user has already specified fixed or variable-length	*
-	* blocks using an ioctl, just believe him. OVERRIDE ALL		*
-	\***************************************************************/
-	if (st->flags & ST_BLOCK_SET)
-	{
-#ifdef	STDEBUG
-	if(st_debug) printf("user has specified %s mode\n",
-		st->flags & ST_FIXEDBLOCKS ?  "fixed" : "variable");
-#endif	/*STDEBUG*/
-		goto done;
+	/*
+	 * Throw another dummy instruction to catch
+	 * 'Unit attention' errors. Some drives appear to give
+	 * these after doing a Load instruction.
+	 * (noteably some DAT drives)
+	 */
+	scsi_test_unit_ready(sc_link, SCSI_SILENT);
+
+	/*
+	 * Some devices can't tell you much until they have been
+	 * asked to look at the media. This quirk does this.
+	 */
+	if (st->quirks & ST_Q_SNS_HLP) {
+		if (errno = st_touch_tape(unit))
+			return errno;
+	}
+	/*
+	 * Load the physical device parameters
+	 * loads: blkmin, blkmax
+	 */
+	if (errno = st_rd_blk_lim(unit, 0)) {
+		return errno;
+	}
+	/*
+	 * Load the media dependent parameters
+	 * includes: media_blksiz,media_density,numblks
+	 * As we have a tape in, it should be reflected here.
+	 * If not you may need the "quirk" above.
+	 */
+	if (errno = st_mode_sense(unit, 0)) {
+		return errno;
+	}
+	/*
+	 * If we have gained a permanent density from somewhere,
+	 * then use it in preference to the one supplied by
+	 * default by the driver.
+	 */
+	if (st->modeflags[dsty] & (DENSITY_SET_BY_QUIRK | DENSITY_SET_BY_USER)) {
+		st->density = st->modes[dsty].density;
+	} else {
+		st->density = st->media_density;
+	}
+	/*
+	 * If we have gained a permanent blocksize
+	 * then use it in preference to the one supplied by
+	 * default by the driver.
+	 */
+	st->flags &= ~ST_FIXEDBLOCKS;
+	if (st->modeflags[dsty] & (BLKSIZE_SET_BY_QUIRK | BLKSIZE_SET_BY_USER)) {
+		st->blksiz = st->modes[dsty].blksiz;
+		if (st->blksiz) {
+			st->flags |= ST_FIXEDBLOCKS;
+		}
+	} else {
+		if (errno = st_decide_mode(unit, FALSE)) {
+			return errno;
+		}
+	}
+	if (errno = st_mode_select(unit, 0)) {
+		printf("st%d: Cannot set selected mode", unit);
+		return errno;
 	}
+	scsi_prevent(sc_link, PR_PREVENT, 0);	/* who cares if it fails? */
+	st->flags &= ~ST_NEW_MOUNT;
+	st->flags |= ST_MOUNTED;
+	sc_link->flags |= SDEV_MEDIA_LOADED;	/* move earlier? */
 
-	/***************************************************************\
-	* If the user hasn't already specified fixed or variable-length	*
-	* blocks and the block size (zero if variable-length), we'll	*
-	* have to try to figure them out ourselves.			*
-	*								*
-	* Our first shot at a method is, "The quirks made me do it!"	*
-	\***************************************************************/
-	switch (st->quirks & (ST_Q_FORCE_FIXED_MODE | ST_Q_FORCE_VAR_MODE))
-	{
-	case	(ST_Q_FORCE_FIXED_MODE | ST_Q_FORCE_VAR_MODE):
-		printf("st%d: bad quirks\n",unit);
+	return 0;
+}
+
+/*
+ * End the present mount session.
+ * Rewind, and optionally eject the tape.
+ * Reset various flags to indicate that all new
+ * operations require another mount operation
+ */
+void
+st_unmount(int unit, boolean eject)
+{
+	struct st_data *st = st_data[unit];
+	struct scsi_link *sc_link = st->sc_link;
+	int32   nmarks;
+
+	if (!(st->flags & ST_MOUNTED))
+		return;
+	SC_DEBUG(sc_link, SDEV_DB1, ("unmounting\n"));
+	st_chkeod(unit, FALSE, &nmarks, SCSI_SILENT);
+	st_rewind(unit, FALSE, SCSI_SILENT);
+	scsi_prevent(sc_link, PR_ALLOW, SCSI_SILENT);
+	if (eject) {
+		st_load(unit, LD_UNLOAD, SCSI_SILENT);
+	}
+	st->flags &= ~(ST_MOUNTED | ST_NEW_MOUNT);
+	sc_link->flags &= ~SDEV_MEDIA_LOADED;
+}
+
+/*
+ * Given all we know about the device, media, mode, 'quirks' and
+ * initial operation, make a decision as to how we should be set
+ * to run (regarding blocking and EOD marks)
+ */
+errval 
+st_decide_mode(unit, first_read)
+	u_int32	unit;
+	boolean	first_read;
+{
+	struct st_data *st = st_data[unit];
+#ifdef SCSIDEBUG
+	struct scsi_link *sc_link = st->sc_link;
+#endif
+
+	SC_DEBUG(sc_link, SDEV_DB2, ("starting block mode decision\n"));
+
+	/*
+	 * If the user hasn't already specified fixed or variable-length
+	 * blocks and the block size (zero if variable-length), we'll
+	 * have to try to figure them out ourselves.
+	 *
+	 * Our first shot at a method is, "The quirks made me do it!"
+	 */
+	switch (st->quirks & (ST_Q_FORCE_FIXED_MODE | ST_Q_FORCE_VAR_MODE)) {
+	case (ST_Q_FORCE_FIXED_MODE | ST_Q_FORCE_VAR_MODE):
+		printf("st%d: bad quirks\n", unit);
 		return (EINVAL);
-	case	ST_Q_FORCE_FIXED_MODE:
+	case ST_Q_FORCE_FIXED_MODE:	/*specified fixed, but not what size */
 		st->flags |= ST_FIXEDBLOCKS;
 		if (st->blkmin && (st->blkmin == st->blkmax))
 			st->blksiz = st->blkmin;
-		else if(st->media_blksiz > 0)
+		else if (st->media_blksiz > 0)
 			st->blksiz = st->media_blksiz;
 		else
 			st->blksiz = DEF_FIXED_BSIZE;
-#ifdef	STDEBUG
-		if(st_debug) printf("Quirks force fixed mode\n");
-#endif	/*STDEBUG*/
+		SC_DEBUG(sc_link, SDEV_DB3, ("Quirks force fixed mode(%d)\n",
+			st->blksiz));
 		goto done;
-	case	ST_Q_FORCE_VAR_MODE:
+	case ST_Q_FORCE_VAR_MODE:
 		st->flags &= ~ST_FIXEDBLOCKS;
 		st->blksiz = 0;
-#ifdef	STDEBUG
-		if(st_debug) printf("Quirks force variable mode\n");
-#endif	/*STDEBUG*/
+		SC_DEBUG(sc_link, SDEV_DB3, ("Quirks force variable mode\n"));
 		goto done;
 	}
-
-	/***************************************************************\
-	* If the drive can only handle fixed-length blocks and only at	*
-	* one size, perhaps we should just do that.			*
-	\***************************************************************/
-	if (st->blkmin && (st->blkmin == st->blkmax))
-	{
+		/*
+		 * If the drive can only handle fixed-length blocks and only at
+		 * one size, perhaps we should just do that.
+		 */
+		if (st->blkmin && (st->blkmin == st->blkmax)) {
 		st->flags |= ST_FIXEDBLOCKS;
 		st->blksiz = st->blkmin;
-#ifdef	STDEBUG
-		if(st_debug) printf("blkmin == blkmax of %d\n",st->blkmin);
-#endif	/*STDEBUG*/
+		SC_DEBUG(sc_link, SDEV_DB3,
+		    ("blkmin == blkmax of %d\n", st->blkmin));
 		goto done;
 	}
-
-	/***************************************************************\
-	* If the tape density mandates use of fixed or variable-length	*
-	* blocks, comply.						*
-	\***************************************************************/
-	switch (st->density)
-	{
-	case	HALFINCH_800:
-	case	HALFINCH_1600:
-	case	HALFINCH_6250:
-	case	DDS:
+	/*
+	 * If the tape density mandates (or even suggests) use of fixed
+	 * or variable-length blocks, comply.
+	 */
+	switch (st->density) {
+	case HALFINCH_800:
+	case HALFINCH_1600:
+	case HALFINCH_6250:
+	case DDS:
 		st->flags &= ~ST_FIXEDBLOCKS;
 		st->blksiz = 0;
-#ifdef	STDEBUG
-	if(st_debug) printf("density specified variable\n");
-#endif	/*STDEBUG*/
+		SC_DEBUG(sc_link, SDEV_DB3, ("density specified variable\n"));
 		goto done;
-	case	QIC_11:
-	case	QIC_24:
-	case	QIC_120:
-	case	QIC_150:
+	case QIC_11:
+	case QIC_24:
+	case QIC_120:
+	case QIC_150:
+	case QIC_525:
+	case QIC_1320:
 		st->flags |= ST_FIXEDBLOCKS;
-		if (st->media_blksiz > 0)
+		if (st->media_blksiz > 0) {
 			st->blksiz = st->media_blksiz;
-		else
+		} else {
 			st->blksiz = DEF_FIXED_BSIZE;
-#ifdef	STDEBUG
-	if(st_debug) printf("density specified fixed\n");
-#endif	/*STDEBUG*/
+		}
+		SC_DEBUG(sc_link, SDEV_DB3, ("density specified fixed\n"));
 		goto done;
 	}
-
-	/***************************************************************\
-	* If we're about to read the tape, perhaps we should choose	*
-	* fixed or variable-length blocks and block size according to	*
-	* what the drive found on the tape.				*
-	\***************************************************************/
-	if (first_read && (!(st->quirks & ST_Q_BLKSIZ) || st->media_blksiz == 0
-	    || st->media_blksiz == DEF_FIXED_BSIZE || st->media_blksiz == 1024))
-	{
-		if (st->media_blksiz == 0)
+	/*
+	 * If we're about to read the tape, perhaps we should choose
+	 * fixed or variable-length blocks and block size according to
+	 * what the drive found on the tape.
+	 */
+	if (first_read
+	    && (!(st->quirks & ST_Q_BLKSIZ)
+		|| (st->media_blksiz == 0)
+		|| (st->media_blksiz == DEF_FIXED_BSIZE)
+		|| (st->media_blksiz == 1024))) {
+		if (st->media_blksiz == 0) {
 			st->flags &= ~ST_FIXEDBLOCKS;
-		else
+		} else {
 			st->flags |= ST_FIXEDBLOCKS;
+		}
 		st->blksiz = st->media_blksiz;
-#ifdef	STDEBUG
-		if(st_debug) printf("Used media_blksiz of %d\n",st->media_blksiz);
-#endif	/*STDEBUG*/
+		SC_DEBUG(sc_link, SDEV_DB3,
+		    ("Used media_blksiz of %d\n", st->media_blksiz));
 		goto done;
 	}
-
-	/***************************************************************\
-	* We're getting no hints from any direction.  Choose variable-	*
-	* length blocks arbitrarily.					*
-	\***************************************************************/
+	/*
+	 * We're getting no hints from any direction.  Choose variable-
+	 * length blocks arbitrarily.
+	 */
 	st->flags &= ~ST_FIXEDBLOCKS;
 	st->blksiz = 0;
-#ifdef	STDEBUG
-	if(st_debug) printf("Give up and default to variable mode\n");
-#endif	/*STDEBUG*/
+	SC_DEBUG(sc_link, SDEV_DB3, ("Give up and default to variable mode\n"));
 done:
-	st->flags &= ~ST_AT_BOM;
-	return (st_mode_select(unit, 0));
+
+	/*
+	 * Decide whether or not to write two file marks to signify end-
+	 * of-data.  Make the decision as a function of density.  If
+	 * the decision is not to use a second file mark, the SCSI BLANK
+	 * CHECK condition code will be recognized as end-of-data when
+	 * first read.
+	 * (I think this should be a by-product of fixed/variable..julian)
+	 */
+	switch (st->density) {
+/*      case    8 mm:   What is the SCSI density code for 8 mm, anyway? */
+	case QIC_11:
+	case QIC_24:
+	case QIC_120:
+	case QIC_150:
+	case QIC_525:
+	case QIC_1320:
+		st->flags &= ~ST_2FM_AT_EOD;
+		break;
+	default:
+		st->flags |= ST_2FM_AT_EOD;
+	}
+	return 0;
 }
 
-/*******************************************************\
-* trim the size of the transfer if needed,		*
-* called by physio					*
-* basically the smaller of our min and the scsi driver's*
-* minphys						*
-\*******************************************************/
-void	stminphys(bp)
-struct buf	*bp;
+/*
+ * trim the size of the transfer if needed,
+ * called by physio
+ * basically the smaller of our min and the scsi driver's
+ * minphys
+ */
+void 
+stminphys(bp)
+	struct buf *bp;
 {
-	(*(st_data[UNIT(bp->b_dev)]->sc_sw->scsi_minphys))(bp);
+	(*(st_data[UNIT(bp->b_dev)]->sc_link->adapter->scsi_minphys)) (bp);
 }
 
-/*******************************************************\
-* Actually translate the requested transfer into	*
-* one the physical driver can understand		*
-* The transfer is described by a buf and will include	*
-* only one physical transfer.				*
-\*******************************************************/
-
-int	ststrategy(bp)
-struct	buf	*bp;
+/*
+ * Actually translate the requested transfer into
+ * one the physical driver can understand
+ * The transfer is described by a buf and will include
+ * only one physical transfer.
+ */
+void 
+ststrategy(bp)
+	struct buf *bp;
 {
-	struct	buf	**dp;
+	struct buf **dp;
 	unsigned char unit;
-	unsigned int opri;
+	u_int32 opri;
 	struct st_data *st;
 
 	ststrats++;
 	unit = UNIT((bp->b_dev));
 	st = st_data[unit];
-#ifdef	STDEBUG
-	if(scsi_debug & PRINTROUTINES) printf("\nststrategy ");
-	if(scsi_debug & SHOWREQUESTS) printf("st%d: %d bytes @ blk%d\n",
-					unit,bp->b_bcount,bp->b_blkno);
-#endif	/*STDEBUG*/
-	/*******************************************************\
-	* If it's a null transfer, return immediatly		*
-	\*******************************************************/
-	if (bp->b_bcount == 0)
-	{
+	SC_DEBUG(st->sc_link, SDEV_DB1,
+	    (" strategy: %d bytes @ blk%d\n", bp->b_bcount, bp->b_blkno));
+	/*
+	 * If it's a null transfer, return immediatly
+	 */
+	if (bp->b_bcount == 0) {
 		goto done;
 	}
-
-	/*******************************************************\
-	* If we're at beginning of medium, now is the time to	*
-	* set medium access density, fixed or variable-blocks	*
-	* and, if fixed, the block size.			*
-	\*******************************************************/
-	if (st->flags & ST_AT_BOM &&
-	    (bp->b_error = st_decide_mode(unit, (bp->b_flags & B_READ) != 0)))
-		goto bad;
-
-	/*******************************************************\
-	* Odd sized request on fixed drives are verboten	*
-	\*******************************************************/
-	if(st->flags & ST_FIXEDBLOCKS)
-	{
-		if(bp->b_bcount % st->blksiz)
-		{
+	/*
+	 * Odd sized request on fixed drives are verboten
+	 */
+	if (st->flags & ST_FIXEDBLOCKS) {
+		if (bp->b_bcount % st->blksiz) {
 			printf("st%d: bad request, must be multiple of %d\n",
-				unit, st->blksiz);
+			    unit, st->blksiz);
 			bp->b_error = EIO;
 			goto bad;
 		}
 	}
-	/*******************************************************\
-	* as are out-of-range requests on variable drives.	*
-	\*******************************************************/
-	else if(bp->b_bcount < st->blkmin || bp->b_bcount > st->blkmax)
-	{
+	/*
+	 * as are out-of-range requests on variable drives.
+	 */
+	else if (bp->b_bcount < st->blkmin || bp->b_bcount > st->blkmax) {
 		printf("st%d: bad request, must be between %d and %d\n",
-			unit, st->blkmin, st->blkmax);
+		    unit, st->blkmin, st->blkmax);
 		bp->b_error = EIO;
 		goto bad;
 	}
-
 	stminphys(bp);
 	opri = splbio();
 
-	/*******************************************************\
-	* Place it in the queue of activities for this tape	*
-	* at the end (a bit silly because we only have on user..*
-	* (but it could fork() ))				*
-	\*******************************************************/
+	/*
+	 * Place it in the queue of activities for this tape
+	 * at the end (a bit silly because we only have on user..
+	 * (but it could fork() ))
+	 */
 	dp = &(st->buf_queue);
-	while (*dp) 
-	{
+	while (*dp) {
 		dp = &((*dp)->b_actf);
-	}	
+	}
 	*dp = bp;
 	bp->b_actf = NULL;
 
-	/*******************************************************\
-	* Tell the device to get going on the transfer if it's	*
-	* not doing anything, otherwise just wait for completion*
-	* (All a bit silly if we're only allowing 1 open but..) *
-	\*******************************************************/
+	/*
+	 * Tell the device to get going on the transfer if it's
+	 * not doing anything, otherwise just wait for completion
+	 * (All a bit silly if we're only allowing 1 open but..)
+	 */
 	ststart(unit);
 
 	splx(opri);
@@ -928,1443 +935,993 @@ struct	buf	*bp;
 bad:
 	bp->b_flags |= B_ERROR;
 done:
-	/*******************************************************\
-	* Correctly set the buf to indicate a completed xfer	*
-	\*******************************************************/
+	/*
+	 * Correctly set the buf to indicate a completed xfer
+	 */
 	iodone(bp);
 	return;
 }
 
+/*
+ * ststart looks to see if there is a buf waiting for the device
+ * and that the device is not already busy. If both are true,
+ * It dequeues the buf and creates a scsi command to perform the
+ * transfer required. The transfer request will call scsi_done
+ * on completion, which will in turn call this routine again
+ * so that the next queued transfer is performed.
+ * The bufs are queued by the strategy routine (ststrategy)
+ *
+ * This routine is also called after other non-queued requests
+ * have been made of the scsi driver, to ensure that the queue
+ * continues to be drained.
+ * ststart() is called at splbio
+ */
+void 
+ststart(unit)
+	u_int32	unit;
+{
+	struct st_data *st = st_data[unit];
+	struct scsi_link *sc_link = st->sc_link;
+	register struct buf *bp = 0;
+	struct scsi_rw_tape cmd;
+	u_int32 flags;
+
+	SC_DEBUG(sc_link, SDEV_DB2, ("ststart "));
+	/*
+	 * See if there is a buf to do and we are not already
+	 * doing one
+	 */
+	while (sc_link->opennings != 0) {
+
+		/* if a special awaits, let it proceed first */
+		if (sc_link->flags & SDEV_WAITING) {
+			wakeup((caddr_t)sc_link);
+			return;
+		}
+		if ((bp = st->buf_queue) == NULL) {
+			return;	/* no work to bother with */
+		}
+		st->buf_queue = bp->b_actf;
+
+		/*
+		 * if the device has been unmounted byt the user
+		 * then throw away all requests until done
+		 */
+		if ((!(st->flags & ST_MOUNTED))
+		    || (!(sc_link->flags & SDEV_MEDIA_LOADED))) {
+			/* make sure that one implies the other.. */
+			sc_link->flags &= ~SDEV_MEDIA_LOADED;
+			goto badnews;
+		}
+		/*
+		 * only FIXEDBLOCK devices have pending operations
+		 */
+		if (st->flags & ST_FIXEDBLOCKS) {
+			/*
+			 * If we are at a filemark but have not reported it yet
+			 * then we should report it now
+			 */
+			if (st->flags & ST_AT_FILEMARK) {
+				if ((bp->b_flags & B_READ) == B_WRITE) {
+					/*
+					 * Handling of ST_AT_FILEMARK in
+					 * st_space will fill in the right file
+					 * mark count.
+					 * Back up over filemark
+					 */
+					if (st_space(unit, 0, SP_FILEMARKS, 0) !=
+					    ESUCCESS)
+						goto badnews;
+				} else {
+					bp->b_resid = bp->b_bcount;
+					bp->b_error = 0;
+					bp->b_flags &= ~B_ERROR;
+					st->flags &= ~ST_AT_FILEMARK;
+					biodone(bp);
+					continue;	/* seek more work */
+				}
+			}
+			/*
+			 * If we are at EIO (e.g. EOM) but have not reported it
+			 * yet then we should report it now
+			 */
+			if (st->flags & ST_EIO_PENDING) {
+				bp->b_resid = bp->b_bcount;
+				bp->b_error = EIO;
+				bp->b_flags |= B_ERROR;
+				st->flags &= ~ST_EIO_PENDING;
+				biodone(bp);
+				continue;	/* seek more work */
+			}
+		}
+		/*
+		 *  Fill out the scsi command
+		 */
+		bzero(&cmd, sizeof(cmd));
+		if ((bp->b_flags & B_READ) == B_WRITE) {
+			cmd.op_code = WRITE_COMMAND_TAPE;
+			st->flags &= ~ST_FM_WRITTEN;
+			st->flags |= ST_WRITTEN;
+			flags = SCSI_DATA_OUT;
+		} else {
+			cmd.op_code = READ_COMMAND_TAPE;
+			flags = SCSI_DATA_IN;
+		}
+		/*
+		 * Handle "fixed-block-mode" tape drives by using the
+		 * block count instead of the length.
+		 */
+		if (st->flags & ST_FIXEDBLOCKS) {
+			cmd.byte2 |= SRWT_FIXED;
+			lto3b(bp->b_bcount / st->blksiz, cmd.len);
+		} else {
+			lto3b(bp->b_bcount, cmd.len);
+		}
+		/*
+		 * go ask the adapter to do all this for us
+		 */
+		if (scsi_scsi_cmd(sc_link,
+			(struct scsi_generic *) &cmd,
+			sizeof(cmd),
+			(u_char *) bp->b_un.b_addr,
+			bp->b_bcount,
+			0,	/* can't retry a read on a tape really */
+			100000,
+			bp,
+			flags | SCSI_NOSLEEP) == SUCCESSFULLY_QUEUED) {
+			stqueues++;
+		} else {
+badnews:
+			printf("st%d: oops not queued\n", unit);
+			bp->b_flags |= B_ERROR;
+			bp->b_error = EIO;
+			biodone(bp);
+		}
+	} /* go back and see if we can cram more work in.. */
+}
 
-
-/*******************************************************\
-* Perform special action on behalf of the user		*
-* Knows about the internals of this device		*
-\*******************************************************/
-stioctl(dev, cmd, arg, mode)
-dev_t dev;
-int cmd;
-caddr_t arg;
+/*
+ * Perform special action on behalf of the user;
+ * knows about the internals of this device
+ */
+errval 
+stioctl(dev, cmd, arg, flag)
+	dev_t   dev;
+	int     cmd;
+	caddr_t arg;
+	int	flag;
 {
-	int errcode = 0;
+	errval  errcode = 0;
 	unsigned char unit;
-	int number,flags,dsty;
-        struct  st_data *st;
-	
-
-	/*******************************************************\
-	* Find the device that the user is talking about	*
-	\*******************************************************/
-	flags = 0;	/* give error messages, act on errors etc. */
+	u_int32 number, flags, dsty;
+	struct st_data *st;
+	u_int32 hold_blksiz;
+	u_int32 hold_density;
+	int32   nmarks;
+	struct mtop *mt = (struct mtop *) arg;
+
+	/*
+	 * Find the device that the user is talking about
+	 */
+	flags = 0;		/* give error messages, act on errors etc. */
 	unit = UNIT(dev);
 	dsty = DSTY(dev);
-        st = st_data[unit];
+	st = st_data[unit];
+	hold_blksiz = st->blksiz;
+	hold_density = st->density;
 
-	switch(cmd)
-	{
+	switch (cmd) {
 
 	case MTIOCGET:
-	    {
-		struct mtget *g = (struct mtget *) arg;
-
-		bzero(g, sizeof(struct mtget));
-		g->mt_type = 0x7;	/* Ultrix compat */ /*?*/
-                if (st->flags & ST_FIXEDBLOCKS) { 
-                        g->mt_bsiz = st->blksiz;
-                } else {
-                        g->mt_bsiz = 0;
-                }
-		g->mt_dns_dflt		= st->modes[0].density;
-		g->mt_dns_dsty1		= st->modes[DSTY1].density;
-		g->mt_dns_dsty2 	= st->modes[DSTY2].density;
-		g->mt_dns_dsty3		= st->modes[DSTY3].density;
-		break;
-	    }
-
-
+		{
+			struct mtget *g = (struct mtget *) arg;
+
+			SC_DEBUG(st->sc_link, SDEV_DB1, ("[ioctl: get status]\n"));
+			bzero(g, sizeof(struct mtget));
+			g->mt_type = 0x7;	/* Ultrix compat *//*? */
+			g->mt_density = st->density;
+			g->mt_blksiz = st->blksiz;
+			g->mt_density0 = st->modes[0].density;
+			g->mt_density1 = st->modes[1].density;
+			g->mt_density2 = st->modes[2].density;
+			g->mt_density3 = st->modes[3].density;
+			g->mt_blksiz0 = st->modes[0].blksiz;
+			g->mt_blksiz1 = st->modes[1].blksiz;
+			g->mt_blksiz2 = st->modes[2].blksiz;
+			g->mt_blksiz3 = st->modes[3].blksiz;
+			break;
+		}
 	case MTIOCTOP:
-	    {
-		int nmarks;
-		struct mtop *mt = (struct mtop *) arg;
-
-#ifdef	STDEBUG
-		if (st_debug)
-			printf("[sctape_sstatus: %x %x]\n",
-				 mt->mt_op, mt->mt_count);
-#endif	/*STDEBUG*/
-
+		{
 
+			SC_DEBUG(st->sc_link, SDEV_DB1, ("[ioctl: op=0x%x count=0x%x]\n",
+				mt->mt_op, mt->mt_count));
 
-		/* compat: in U*x it is a short */
-		number = mt->mt_count;
-		switch ((short)(mt->mt_op))
-		{
-		case MTWEOF:	/* write an end-of-file record */
-			errcode = st_write_filemarks(unit,number,flags);
-			break;
-		case MTBSF:	/* backward space file */
-			number = -number;
-		case MTFSF:	/* forward space file */
-			errcode = st_chkeod(unit, FALSE, &nmarks, flags);
-			if (errcode == ESUCCESS)
-				errcode = st_space(unit, number - nmarks,
-				    SP_FILEMARKS, flags);
-			break;
-		case MTBSR:	/* backward space record */
-			number = -number;
-		case MTFSR:	/* forward space record */
-			errcode = st_chkeod(unit, TRUE, &nmarks, flags);
-			if (errcode == ESUCCESS)
-				errcode = st_space(unit,number,SP_BLKS,flags);
-			break;
-		case MTREW:	/* rewind */
-			errcode = st_rewind(unit,FALSE,flags);
-			break;
-		case MTOFFL:	/* rewind and put the drive offline */
-			if(st_rewind(unit,FALSE,flags))
-			{
-				printf("st%d: rewind failed, unit still loaded\n",
-					unit);
-			}
-			else
-			{
-				st_prevent(unit,PR_ALLOW,0);
-				st_load(unit,LD_UNLOAD,flags);
-			}
-			break;
-		case MTNOP:	/* no operation, sets status only */
-		case MTCACHE:	/* enable controller cache */
-		case MTNOCACHE:	/* disable controller cache */
-			break;
-		case MTSETBSIZ: /* Set block size for device */
-			if (!(st->flags & ST_AT_BOM))
-			{
-				errcode =  EINVAL;
+			/* compat: in U*x it is a short */
+			number = mt->mt_count;
+			switch ((short) (mt->mt_op)) {
+			case MTWEOF:	/* write an end-of-file record */
+				errcode = st_write_filemarks(unit, number, flags);
 				break;
-			}
-			if (number == 0)
-			{
-				st->flags &= ~ST_FIXEDBLOCKS;
-			}
-			else
-			{
-				if ((st->blkmin || st->blkmax) /* they exist */
-			   	  && ((number < st->blkmin 
-				    || number > st->blkmax)))
-				{
+			case MTBSF:	/* backward space file */
+				number = -number;
+			case MTFSF:	/* forward space file */
+				errcode = st_chkeod(unit, FALSE, &nmarks, flags);
+				if (errcode == ESUCCESS)
+					errcode = st_space(unit, number - nmarks,
+					    SP_FILEMARKS, flags);
+				break;
+			case MTBSR:	/* backward space record */
+				number = -number;
+			case MTFSR:	/* forward space record */
+				errcode = st_chkeod(unit, TRUE, &nmarks, flags);
+				if (errcode == ESUCCESS)
+					errcode = st_space(unit, number, SP_BLKS, flags);
+				break;
+			case MTREW:	/* rewind */
+				errcode = st_rewind(unit, FALSE, flags);
+				break;
+			case MTOFFL:	/* rewind and put the drive offline */
+				st_unmount(unit, EJECT);
+				break;
+			case MTNOP:	/* no operation, sets status only */
+			case MTCACHE:	/* enable controller cache */
+			case MTNOCACHE:	/* disable controller cache */
+				break;
+			case MTSETBSIZ:	/* Set block size for device */
+#ifdef	NOTYET
+				if (!(st->flags & ST_NEW_MOUNT)) {
+					uprintf("re-mount tape before changing blocksize");
 					errcode = EINVAL;
 					break;
 				}
-				st->flags |= ST_FIXEDBLOCKS;
-			}
-			st->blksiz = number;
-			st->flags |= ST_BLOCK_SET;
-                        break;
+#endif
+				if (number == 0) {
+					st->flags &= ~ST_FIXEDBLOCKS;
+				} else {
+					if ((st->blkmin || st->blkmax)	/* they exist */
+					    &&((number < st->blkmin
+						    || number > st->blkmax))) {
+						errcode = EINVAL;
+						break;
+					}
+					st->flags |= ST_FIXEDBLOCKS;
+				}
+				st->blksiz = number;
+				st->flags |= ST_BLOCK_SET;	/*XXX */
+				goto try_new_value;
 
-			/* How do we check that the drive can handle
-			   the requested density ? */
+			case MTSETDNSTY:	/* Set density for device and mode */
+				if (number > SCSI_2_MAX_DENSITY_CODE) {
+					errcode = EINVAL;
+				} else {
+					st->density = number;
+				}
+				goto try_new_value;
 
-                case MTSETDNSTY: /* Set density for device and mode */
-			if (number < 0 || number > SCSI_2_MAX_DENSITY_CODE)
-			{
+			default:
 				errcode = EINVAL;
 			}
-			else
-			{ 
-				st->modes[dsty].density = number;
-			}
 			break;
-
-		default:
-			errcode = EINVAL;
 		}
-		break;
-	    }
 	case MTIOCIEOT:
 	case MTIOCEEOT:
 		break;
 	default:
-		errcode = EINVAL;
+		if(MODE(dev) == CTLMODE)
+			errcode = scsi_do_ioctl(st->sc_link,cmd,arg,flag);
+		else
+			errcode = ENOTTY;
+		break;
 	}
-
 	return errcode;
+/*-----------------------------*/
+try_new_value:
+	/*
+	 * Check that the mode being asked for is aggreeable to the
+	 * drive. If not, put it back the way it was.
+	 */
+	if (errcode = st_mode_select(unit, 0)) {	/* put it back as it was */
+		printf("st%d: Cannot set selected mode", unit);
+		st->density = hold_density;
+		st->blksiz = hold_blksiz;
+		if (st->blksiz) {
+			st->flags |= ST_FIXEDBLOCKS;
+		} else {
+			st->flags &= ~ST_FIXEDBLOCKS;
+		}
+		return (errcode);
+	}
+	/*
+	 * As the drive liked it, if we are setting a new default,
+	 * set it into the structures as such.
+	 * 
+	 * The means for deciding this are not finalised yet
+	 */
+	if (MODE(dev) == 0x03) {
+		/* special mode */
+		/* XXX */
+		switch ((short) (mt->mt_op)) {
+		case MTSETBSIZ:
+			st->modes[dsty].blksiz = st->blksiz;
+			st->modeflags[dsty] |= BLKSIZE_SET_BY_USER;
+			break;
+		case MTSETDNSTY:
+			st->modes[dsty].density = st->density;
+			st->modeflags[dsty] |= DENSITY_SET_BY_USER;
+			break;
+		}
+	}
+	return 0;
 }
 
-/*******************************************************\
-* Do a synchronous read.				*
-\*******************************************************/
-int st_read(unit, buf, size, flags)
-int	unit, size, flags;
-char	*buf;
+/*
+ * Do a synchronous read.
+ */
+errval 
+st_read(unit, buf, size, flags)
+	u_int32 unit, size, flags;
+	char   *buf;
 {
-	int error;
 	struct scsi_rw_tape scsi_cmd;
 	struct st_data *st = st_data[unit];
 
-	/*******************************************************\
-	* If it's a null transfer, return immediatly		*
-	\*******************************************************/
-	if (size == 0)
-	{
-		return(ESUCCESS);
+	/*
+	 * If it's a null transfer, return immediatly
+	 */
+	if (size == 0) {
+		return (ESUCCESS);
 	}
-
-	/*******************************************************\
-	* If we're at beginning of medium, now is the time to	*
-	* set medium access density, fixed or variable-blocks	*
-	* and, if fixed, the block size.			*
-	\*******************************************************/
-	if (st->flags & ST_AT_BOM && (error = st_decide_mode(unit, TRUE)))
-		return (error);
-
 	bzero(&scsi_cmd, sizeof(scsi_cmd));
 	scsi_cmd.op_code = READ_COMMAND_TAPE;
-	scsi_cmd.byte2 |= st->flags & ST_FIXEDBLOCKS ? SRWT_FIXED : 0;
-	lto3b(scsi_cmd.byte2 & SRWT_FIXED ?
-	    size / (st->blksiz ? st->blksiz : DEF_FIXED_BSIZE) : size,
-	    scsi_cmd.len);
-	return (st_scsi_cmd(unit,
-			&scsi_cmd,
-			sizeof(scsi_cmd),
-			buf,
-			size,
-			100000,
-			NULL,
-			flags | SCSI_DATA_IN));
-}
-
-/*******************************************************\
-* Get scsi driver to send a "are you ready" command	*
-\*******************************************************/
-st_test_ready(unit,flags)
-int	unit,flags;
-{
-	struct	scsi_test_unit_ready scsi_cmd;
-
-	bzero(&scsi_cmd, sizeof(scsi_cmd));
-	scsi_cmd.op_code = TEST_UNIT_READY;
-
-	return (st_scsi_cmd(unit,
-			&scsi_cmd,
-			sizeof(scsi_cmd),
-			0,
-			0,
-			100000,
-			NULL,
-			flags));
+	if (st->flags & ST_FIXEDBLOCKS) {
+		scsi_cmd.byte2 |= SRWT_FIXED;
+		lto3b(size / (st->blksiz ? st->blksiz : DEF_FIXED_BSIZE),
+		    scsi_cmd.len);
+	} else {
+		lto3b(size, scsi_cmd.len);
+	}
+	return (scsi_scsi_cmd(st->sc_link,
+		(struct scsi_generic *) &scsi_cmd,
+		sizeof(scsi_cmd),
+		(u_char *) buf,
+		size,
+		0,		/* not on io commands */
+		100000,
+		NULL,
+		flags | SCSI_DATA_IN));
 }
-
-
 #ifdef	__STDC__
 #define b2tol(a)	(((unsigned)(a##_1) << 8) + (unsigned)a##_0 )
 #else
 #define b2tol(a)	(((unsigned)(a/**/_1) << 8) + (unsigned)a/**/_0 )
 #endif
 
-/*******************************************************\
-* Ask the drive what it's min and max blk sizes are.	*
-\*******************************************************/
+/*
+ * Ask the drive what it's min and max blk sizes are.
+ */
+errval 
 st_rd_blk_lim(unit, flags)
-int	unit,flags;
+	u_int32 unit, flags;
 {
-	struct	scsi_blk_limits scsi_cmd;
+	struct scsi_blk_limits scsi_cmd;
 	struct scsi_blk_limits_data scsi_blkl;
 	struct st_data *st = st_data[unit];
-	int	errno;
-
-	/*******************************************************\
-	* First check if we have it all loaded			*
-	\*******************************************************/
-	if ((st->flags & ST_INFO_VALID)) return 0;
-
-	/*******************************************************\
-	* do a 'Read Block Limits'				*
-	\*******************************************************/
+	errval  errno;
+	struct scsi_link *sc_link = st->sc_link;
+
+	/*
+	 * First check if we have it all loaded
+	 */
+	if ((sc_link->flags & SDEV_MEDIA_LOADED))
+		return 0;
+
+	/*
+	 * do a 'Read Block Limits'
+	 */
 	bzero(&scsi_cmd, sizeof(scsi_cmd));
 	scsi_cmd.op_code = READ_BLK_LIMITS;
 
-	/*******************************************************\
-	* do the command,	update the global values	*
-	\*******************************************************/
-	if ( errno = st_scsi_cmd(unit,
-			&scsi_cmd,
-			sizeof(scsi_cmd),
-			&scsi_blkl,
-			sizeof(scsi_blkl),
-			5000,
-			NULL,
-			flags | SCSI_DATA_IN))
-	{
+	/*
+	 * do the command, update the global values
+	 */
+	if (errno = scsi_scsi_cmd(sc_link,
+		(struct scsi_generic *) &scsi_cmd,
+		sizeof(scsi_cmd),
+		(u_char *) & scsi_blkl,
+		sizeof(scsi_blkl),
+		ST_RETRIES,
+		5000,
+		NULL,
+		flags | SCSI_DATA_IN)) {
 		return errno;
-	} 
+	}
 	st->blkmin = b2tol(scsi_blkl.min_length);
 	st->blkmax = _3btol(&scsi_blkl.max_length_2);
 
-#ifdef	STDEBUG
-	if (st_debug)
-	{
-		printf("(%d <= blksiz <= %d)\n", st->blkmin, st->blkmax);
-	}
-#endif	/*STDEBUG*/
+	SC_DEBUG(sc_link, SDEV_DB3,
+	    ("(%d <= blksiz <= %d)\n", st->blkmin, st->blkmax));
 	return 0;
 }
 
-/*******************************************************\
-* Get the scsi driver to send a full inquiry to the	*
-* device and use the results to fill out the global 	*
-* parameter structure.					*
-*							*
-* called from:						*
-* attach						*
-* open							*
-* ioctl (to reset original blksize)			*
-\*******************************************************/
+/*
+ * Get the scsi driver to send a full inquiry to the
+ * device and use the results to fill out the global 
+ * parameter structure.
+ *
+ * called from:
+ * attach
+ * open
+ * ioctl (to reset original blksize)
+ */
+errval 
 st_mode_sense(unit, flags)
-int	unit,flags;
+	u_int32 unit, flags;
 {
-	int	scsi_sense_len;
-	int	errno;
-	char	*scsi_sense_ptr;
-	struct scsi_mode_sense		scsi_cmd;
-	struct scsi_sense
-	{
-		struct	scsi_mode_header header;
-		struct	blk_desc	blk_desc;
-	}scsi_sense;
+	u_int32 scsi_sense_len;
+	errval  errno;
+	char   *scsi_sense_ptr;
+	struct scsi_mode_sense scsi_cmd;
+	struct scsi_sense {
+		struct scsi_mode_header header;
+		struct blk_desc blk_desc;
+	} scsi_sense;
+
+	struct scsi_sense_page_0 {
+		struct scsi_mode_header header;
+		struct blk_desc blk_desc;
+		unsigned char sense_data[PAGE_0_SENSE_DATA_SIZE];
+			/* Tandberg tape drives returns page 00
+			 * with the sense data, whether or not
+			 * you want it( ie the don't like you
+			 * saying you want anything less!!!!!
+			 * They also expect page 00
+			 * back when you issue a mode select
+			 */
+	} scsi_sense_page_0;
+	struct st_data *st = st_data[unit];
+	struct scsi_link *sc_link = st->sc_link;
 
-	struct scsi_sense_page_0
-	{
-		struct	scsi_mode_header header;
-		struct	blk_desc	blk_desc;
-                unsigned char   sense_data[PAGE_0_SENSE_DATA_SIZE];
-                        /* Tandberg tape drives returns page 00 */
-                        /* with the sense data, whether or not */
-                        /* you want it( ie the don't like you  */
-                        /* saying you want anything less!!!!!  */
-                        /* They also expect page 00 */
-                        /* back when you issue a mode select */
-	}scsi_sense_page_0;
-	struct	st_data *st = st_data[unit];
-	
-	/*******************************************************\
-	* First check if we have it all loaded			*
-	\*******************************************************/
-	if ((st->flags & ST_INFO_VALID)) return 0;
-
-	/*******************************************************\
-	* Define what sort of structure we're working with	*
-	\*******************************************************/
-	if (st->quirks & ST_Q_NEEDS_PAGE_0)
-	{
+	/*
+	 * Define what sort of structure we're working with
+	 */
+	if (st->quirks & ST_Q_NEEDS_PAGE_0) {
 		scsi_sense_len = sizeof(scsi_sense_page_0);
 		scsi_sense_ptr = (char *) &scsi_sense_page_0;
-	}
-	else
-	{
+	} else {
 		scsi_sense_len = sizeof(scsi_sense);
 		scsi_sense_ptr = (char *) &scsi_sense;
 	}
-
-	/*******************************************************\
-	* Set up a mode sense 					*
-	\*******************************************************/
+	/*
+	 * Set up a mode sense 
+	 */
 	bzero(&scsi_cmd, sizeof(scsi_cmd));
 	scsi_cmd.op_code = MODE_SENSE;
 	scsi_cmd.length = scsi_sense_len;
 
-	/*******************************************************\
-	* do the command, but we don't need the results		*
-	* just print them for our interest's sake, if asked,	*
-	* or if we need it as a template for the mode select	*
-	* store it away.					*
-	\*******************************************************/
-	if (errno = st_scsi_cmd(unit,
-			&scsi_cmd,
-			sizeof(scsi_cmd),
-			scsi_sense_ptr,
-			scsi_sense_len,
-			5000,
-			NULL,
-			flags | SCSI_DATA_IN) )
-	{
+	/*
+	 * do the command, but we don't need the results
+	 * just print them for our interest's sake, if asked,
+	 * or if we need it as a template for the mode select
+	 * store it away.
+	 */
+	if (errno = scsi_scsi_cmd(sc_link,
+		(struct scsi_generic *) &scsi_cmd,
+		sizeof(scsi_cmd),
+		(u_char *) scsi_sense_ptr,
+		scsi_sense_len,
+		ST_RETRIES,
+		5000,
+		NULL,
+		flags | SCSI_DATA_IN)) {
 		return errno;
-	} 
-	st->numblks = _3btol(&(((struct scsi_sense *)scsi_sense_ptr)->blk_desc.nblocks));
-	st->media_blksiz = _3btol(&(((struct scsi_sense *)scsi_sense_ptr)->blk_desc.blklen));
-	st->media_density = ((struct scsi_sense *)scsi_sense_ptr)->blk_desc.density;
-	if (((struct scsi_sense *)scsi_sense_ptr)->header.dev_spec &
-	    SMH_DSP_WRITE_PROT)
+	}
+	st->numblks = _3btol(((struct scsi_sense *)scsi_sense_ptr)->blk_desc.nblocks);
+	st->media_blksiz = _3btol(((struct scsi_sense *)scsi_sense_ptr)->blk_desc.blklen);
+	st->media_density = ((struct scsi_sense *) scsi_sense_ptr)->blk_desc.density;
+	if (((struct scsi_sense *) scsi_sense_ptr)->header.dev_spec &
+	    SMH_DSP_WRITE_PROT) {
 		st->flags |= ST_READONLY;
-#ifdef	STDEBUG
-	if (st_debug)
-	{
-		printf("st%d: density code 0x%x, %d-byte blocks, write-%s, ",
-		    unit, st->media_density, st->media_blksiz,
-		    st->flags & ST_READONLY ? "protected" : "enabled");
-		printf("%sbuffered\n",
-	    	    ((struct scsi_sense *)scsi_sense_ptr)->header.dev_spec
-		    & SMH_DSP_BUFF_MODE ? "" : "un");
 	}
-#endif	/*STDEBUG*/
-	if (st->quirks & ST_Q_NEEDS_PAGE_0)
-	{
-		bcopy(((struct scsi_sense_page_0 *)scsi_sense_ptr)->sense_data, 
-			st->sense_data, 
-			sizeof(((struct scsi_sense_page_0 *)scsi_sense_ptr)->sense_data));
+	SC_DEBUG(sc_link, SDEV_DB3,
+	    ("density code 0x%x, %d-byte blocks, write-%s, ",
+		st->media_density, st->media_blksiz,
+		st->flags & ST_READONLY ? "protected" : "enabled"));
+	SC_DEBUG(sc_link, SDEV_DB3,
+	    ("%sbuffered\n",
+		((struct scsi_sense *) scsi_sense_ptr)->header.dev_spec
+		& SMH_DSP_BUFF_MODE ? "" : "un"));
+	if (st->quirks & ST_Q_NEEDS_PAGE_0) {
+		bcopy(((struct scsi_sense_page_0 *) scsi_sense_ptr)->sense_data,
+		    st->sense_data,
+		    sizeof(((struct scsi_sense_page_0 *) scsi_sense_ptr)->sense_data));
 	}
+	sc_link->flags |= SDEV_MEDIA_LOADED;
 	return 0;
 }
 
-/*******************************************************\
-* Send a filled out parameter structure to the drive to	*
-* set it into the desire modes etc.			*
-\*******************************************************/
+/*
+ * Send a filled out parameter structure to the drive to
+ * set it into the desire modes etc.
+ */
+errval 
 st_mode_select(unit, flags)
-int	unit, flags;
+	u_int32 unit, flags;
 {
-	int	dat_len;
-	char	*dat_ptr;
+	u_int32 dat_len;
+	char   *dat_ptr;
 	struct scsi_mode_select scsi_cmd;
-	struct dat
-	{
-		struct	scsi_mode_header header;
-		struct	blk_desc	blk_desc;
-	}dat;
-	struct dat_page_0
-	{
-		struct	scsi_mode_header header;
-		struct	blk_desc	blk_desc;
-                unsigned char   sense_data[PAGE_0_SENSE_DATA_SIZE];
-	}dat_page_0;
-	struct	st_data *st = st_data[unit];
-
-	/*******************************************************\
-	* Define what sort of structure we're working with	*
-	\*******************************************************/
-	if (st->quirks & ST_Q_NEEDS_PAGE_0)
-	{
+	struct dat {
+		struct scsi_mode_header header;
+		struct blk_desc blk_desc;
+	} dat;
+	struct dat_page_0 {
+		struct scsi_mode_header header;
+		struct blk_desc blk_desc;
+		unsigned char sense_data[PAGE_0_SENSE_DATA_SIZE];
+	} dat_page_0;
+	struct st_data *st = st_data[unit];
+
+	/*
+	 * Define what sort of structure we're working with
+	 */
+	if (st->quirks & ST_Q_NEEDS_PAGE_0) {
 		dat_len = sizeof(dat_page_0);
 		dat_ptr = (char *) &dat_page_0;
-	}
-	else
-	{
+	} else {
 		dat_len = sizeof(dat);
 		dat_ptr = (char *) &dat;
 	}
-		
-	/*******************************************************\
-	* Set up for a mode select				*
-	\*******************************************************/
+	/*
+	 * Set up for a mode select
+	 */
 	bzero(dat_ptr, dat_len);
 	bzero(&scsi_cmd, sizeof(scsi_cmd));
 	scsi_cmd.op_code = MODE_SELECT;
 	scsi_cmd.length = dat_len;
-	((struct dat *)dat_ptr)->header.blk_desc_len = sizeof(struct  blk_desc);
-	((struct dat *)dat_ptr)->header.dev_spec |= SMH_DSP_BUFF_MODE_ON;
-	((struct dat *)dat_ptr)->blk_desc.density = st->density;
-	if(st->flags & ST_FIXEDBLOCKS)
-	{
-		lto3b( st->blksiz , ((struct dat *)dat_ptr)->blk_desc.blklen);
+	((struct dat *) dat_ptr)->header.blk_desc_len = sizeof(struct blk_desc);
+	((struct dat *) dat_ptr)->header.dev_spec |= SMH_DSP_BUFF_MODE_ON;
+	((struct dat *) dat_ptr)->blk_desc.density = st->density;
+	if (st->flags & ST_FIXEDBLOCKS) {
+		lto3b(st->blksiz, ((struct dat *) dat_ptr)->blk_desc.blklen);
 	}
-	if (st->quirks & ST_Q_NEEDS_PAGE_0)
-	{
-		bcopy(st->sense_data, ((struct dat_page_0 *)dat_ptr)->sense_data, 
-			sizeof(((struct dat_page_0 *)dat_ptr)->sense_data));
-			/* the Tandberg tapes need the block size to */
-			/* be set on each mode sense/select. */
+	if (st->quirks & ST_Q_NEEDS_PAGE_0) {
+		bcopy(st->sense_data, ((struct dat_page_0 *) dat_ptr)->sense_data,
+		    sizeof(((struct dat_page_0 *) dat_ptr)->sense_data));
+		/* the Tandberg tapes need the block size to */
+		/* be set on each mode sense/select. */
 	}
-	/*******************************************************\
-	* do the command					*
-	\*******************************************************/
-	return (st_scsi_cmd(unit,
-			&scsi_cmd,
-			sizeof(scsi_cmd),
-			dat_ptr,
-			dat_len,
-			5000,
-			NULL,
-			flags | SCSI_DATA_OUT) );
+	/*
+	 * do the command
+	 */
+	return (scsi_scsi_cmd(st->sc_link,
+		(struct scsi_generic *) &scsi_cmd,
+		sizeof(scsi_cmd),
+		(u_char *) dat_ptr,
+		dat_len,
+		ST_RETRIES,
+		5000,
+		NULL,
+		flags | SCSI_DATA_OUT));
 }
 
-/*******************************************************\
-* skip N blocks/filemarks/seq filemarks/eom		*
-\*******************************************************/
-st_space(unit,number,what,flags)
-int	unit,number,what,flags;
+/*
+ * skip N blocks/filemarks/seq filemarks/eom
+ */
+errval 
+st_space(unit, number, what, flags)
+	u_int32 unit, what, flags;
+	int32   number;
 {
-	int error;
+	errval  error;
 	struct scsi_space scsi_cmd;
-	struct	st_data *st = st_data[unit];
-
-	/*******************************************************\
-	* If we're at beginning of medium, now is the time to	*
-	* set medium access density, fixed or variable-blocks	*
-	* and, if fixed, the block size.			*
-	\*******************************************************/
-	if (st->flags & ST_AT_BOM &&
-	    (error = st_decide_mode(unit, TRUE)))
-		return (error);
+	struct st_data *st = st_data[unit];
 
-	switch (what)
-	{
-	case	SP_BLKS:
-		if (st->flags & ST_PER_ACTION)
-		{
-			if (number > 0)
-			{
+	switch (what) {
+	case SP_BLKS:
+		if (st->flags & ST_PER_ACTION) {
+			if (number > 0) {
 				st->flags &= ~ST_PER_ACTION;
-				return(EIO);
-			}
-			else if (number < 0)
-			{
-				if (st->flags & ST_AT_FILEMARK)
-				{
-					/*******************************\
-					* Handling of ST_AT_FILEMARK	*
-					* in st_space will fill in the	*
-					* right file mark count.	*
-					\*******************************/
+				return (EIO);
+			} else if (number < 0) {
+				if (st->flags & ST_AT_FILEMARK) {
+					/*
+					 * Handling of ST_AT_FILEMARK
+					 * in st_space will fill in the
+					 * right file mark count.
+					 */
 					error = st_space(unit, 0, SP_FILEMARKS,
 					    flags);
-					if (error) return(error);
+					if (error)
+						return (error);
 				}
-				if (st->flags & ST_BLANK_READ)
-				{
+				if (st->flags & ST_BLANK_READ) {
 					st->flags &= ~ST_BLANK_READ;
-					return(EIO);
+					return (EIO);
 				}
 				st->flags &= ~ST_EIO_PENDING;
 			}
 		}
 		break;
-	case	SP_FILEMARKS:
-		if (st->flags & ST_EIO_PENDING)
-		{
-			if (number > 0)
-			{
+	case SP_FILEMARKS:
+		if (st->flags & ST_EIO_PENDING) {
+			if (number > 0) {	/* pretend we just discover the error */
 				st->flags &= ~ST_EIO_PENDING;
-				return(EIO);
-			}
-			else if (number < 0)
+				return (EIO);
+			} else if (number < 0) {	/* back away from the error */
 				st->flags &= ~ST_EIO_PENDING;
+			}
 		}
-		if (st->flags & ST_AT_FILEMARK)
-		{
+		if (st->flags & ST_AT_FILEMARK) {
 			st->flags &= ~ST_AT_FILEMARK;
 			number--;
 		}
-		if (st->flags & ST_BLANK_READ && number < 0)
-		{
+		if ((st->flags & ST_BLANK_READ) && (number < 0)) {	/* back away from unwritten tape */
 			st->flags &= ~ST_BLANK_READ;
-			number++;
+			number++;	/* dubious */
 		}
 	}
-	if (number == 0)
-		return(ESUCCESS);
+	if (number == 0) {
+		return (ESUCCESS);
+	}
 	bzero(&scsi_cmd, sizeof(scsi_cmd));
 	scsi_cmd.op_code = SPACE;
 	scsi_cmd.byte2 = what & SS_CODE;
-	lto3b(number,scsi_cmd.number);
-	return (st_scsi_cmd(unit,
-			&scsi_cmd,
-			sizeof(scsi_cmd),
-			0,
-			0,
-			600000, /* 10 mins enough? */
-			NULL,
-			flags));
+	lto3b(number, scsi_cmd.number);
+	return (scsi_scsi_cmd(st->sc_link,
+		(struct scsi_generic *) &scsi_cmd,
+		sizeof(scsi_cmd),
+		0,
+		0,
+		0,		/* no retries please , just fail */
+		600000,		/* 10 mins enough? */
+		NULL,
+		flags));
 }
-/*******************************************************\
-* write N filemarks					*
-\*******************************************************/
-st_write_filemarks(unit,number,flags)
-int	unit,number,flags;
+
+/*
+ * write N filemarks
+ */
+errval 
+st_write_filemarks(unit, number, flags)
+	u_int32 unit, flags;
+	int32   number;
 {
-	int error;
 	struct scsi_write_filemarks scsi_cmd;
-	struct	st_data	*st = st_data[unit];
-
-	/*******************************************************\
-	* It's hard to write a negative number of file marks.	*
-	* Don't try.						*
-	\*******************************************************/
-	if (number < 0)
-		return (EINVAL);
-
-	/*******************************************************\
-	* If we're at beginning of medium, now is the time to	*
-	* set medium access density, fixed or variable-blocks	*
-	* and, if fixed, the block size.			*
-	\*******************************************************/
-	if (st->flags & ST_AT_BOM && number > 0 &&
-	    (error = st_decide_mode(unit, FALSE)))
-		return (error);
+	struct st_data *st = st_data[unit];
 
-	switch (number)
-	{
-	case	0:	/* really a command to sync the drive's buffers */
+	/*
+	 * It's hard to write a negative number of file marks.
+	 * Don't try.
+	 */
+	if (number < 0) {
+		return EINVAL;
+	}
+	switch (number) {
+	case 0:		/* really a command to sync the drive's buffers */
 		break;
-	case	1:
-		if (st->flags & ST_FM_WRITTEN)
+	case 1:
+		if (st->flags & ST_FM_WRITTEN) {	/* already have one down */
 			st->flags &= ~ST_WRITTEN;
-		else
+		} else {
 			st->flags |= ST_FM_WRITTEN;
+		}
 		st->flags &= ~ST_PER_ACTION;
 		break;
 	default:
 		st->flags &= ~(ST_PER_ACTION | ST_WRITTEN);
 	}
-
 	bzero(&scsi_cmd, sizeof(scsi_cmd));
 	scsi_cmd.op_code = WRITE_FILEMARKS;
-	lto3b(number,scsi_cmd.number);
-	return (st_scsi_cmd(unit,
-			&scsi_cmd,
-			sizeof(scsi_cmd),
-			0,
-			0,
-			100000, /* 10 secs.. (may need to repos head )*/
-			NULL,
-			flags) );
+	lto3b(number, scsi_cmd.number);
+	return scsi_scsi_cmd(st->sc_link,
+		(struct scsi_generic *) &scsi_cmd,
+		sizeof(scsi_cmd),
+		0,
+		0,
+		0,		/* no retries, just fail */
+		100000,		/* 10 secs.. (may need to repos head ) */
+		NULL,
+		flags);
 }
 
-/***************************************************************\
-* Make sure the right number of file marks is on tape if the	*
-* tape has been written.  If the position argument is true,	*
-* leave the tape positioned where it was originally.		*
-*								*
-* nmarks returns the number of marks to skip (or, if position	*
-* true, which were skipped) to get back original position.	*
-\***************************************************************/
+/*
+ * Make sure the right number of file marks is on tape if the
+ * tape has been written.  If the position argument is true,
+ * leave the tape positioned where it was originally.
+ *
+ * nmarks returns the number of marks to skip (or, if position
+ * true, which were skipped) to get back original position.
+ */
+int32 
 st_chkeod(unit, position, nmarks, flags)
-int	unit;
-int	position;
-int	*nmarks;
-int	flags;
+	u_int32 unit;
+	boolean position;
+	int32  *nmarks;
+	u_int32 flags;
 {
-	int	error;
-	struct	st_data *st = st_data[unit];
+	errval  error;
+	struct st_data *st = st_data[unit];
 
-	switch (st->flags & (ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD))
-	{
+	switch (st->flags & (ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD)) {
 	default:
 		*nmarks = 0;
-		return(ESUCCESS);
-	case	ST_WRITTEN:
-	case	ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD:
+		return (ESUCCESS);
+	case ST_WRITTEN:
+	case ST_WRITTEN | ST_FM_WRITTEN | ST_2FM_AT_EOD:
 		*nmarks = 1;
 		break;
-	case	ST_WRITTEN | ST_2FM_AT_EOD:
+	case ST_WRITTEN | ST_2FM_AT_EOD:
 		*nmarks = 2;
 	}
 	error = st_write_filemarks(unit, *nmarks, flags);
-	if (position && error == ESUCCESS)
+	if (position && (error == ESUCCESS))
 		error = st_space(unit, -*nmarks, SP_FILEMARKS, flags);
 	return (error);
 }
 
-/*******************************************************\
-* load/unload (with retension if true)			*
-\*******************************************************/
-st_load(unit,type,flags)
-int	unit,type,flags;
+/*
+ * load/unload (with retension if true)
+ */
+errval 
+st_load(unit, type, flags)
+	u_int32 unit, type, flags;
 {
-	struct  scsi_load  scsi_cmd;
-	struct	st_data	*st = st_data[unit];
+	struct scsi_load scsi_cmd;
+	struct st_data *st = st_data[unit];
+	struct scsi_link *sc_link = st->sc_link;
 
-	st->flags &= ~ST_PER_MEDIA;
 	bzero(&scsi_cmd, sizeof(scsi_cmd));
-	if (type == LD_LOAD)
-	{
-		/*scsi_cmd.how |= LD_RETEN;*/
-		st->flags |= ST_AT_BOM;
-	}
-	else
-	{
-		int	error, nmarks;
+	if (type != LD_LOAD) {
+		errval  error;
+		int32   nmarks;
 
 		error = st_chkeod(unit, FALSE, &nmarks, flags);
-		if (error != ESUCCESS) return(error);
-		st->flags &= ~ST_INFO_VALID;
+		if (error != ESUCCESS)
+			return (error);
+		sc_link->flags &= ~SDEV_MEDIA_LOADED;
 	}
-	if(st->quirks & ST_Q_IGNORE_LOADS) return(0);
+	if (st->quirks & ST_Q_IGNORE_LOADS)
+		return (0);
 	scsi_cmd.op_code = LOAD_UNLOAD;
 	scsi_cmd.how |= type;
-	return (st_scsi_cmd(unit,
-			&scsi_cmd,
-			sizeof(scsi_cmd),
-			0,
-			0,
-			300000, /* 5 min */
-			NULL,
-			flags));
+	return (scsi_scsi_cmd(st->sc_link,
+		(struct scsi_generic *) &scsi_cmd,
+		sizeof(scsi_cmd),
+		0,
+		0,
+		ST_RETRIES,
+		300000,		/* 5 min */
+		NULL,
+		flags));
 }
-/*******************************************************\
-* Prevent or allow the user to remove the tape		*
-\*******************************************************/
-st_prevent(unit,type,flags)
-int	unit,type,flags;
-{
-	struct	scsi_prevent	scsi_cmd;
 
-	if (type == PR_ALLOW)
-	{
-		int	error, nmarks;
-
-		error = st_chkeod(unit, TRUE, &nmarks, flags);
-		if (error != ESUCCESS) return(error);
-		st_data[unit]->flags &= ~ST_INFO_VALID;
-	}
-	bzero(&scsi_cmd, sizeof(scsi_cmd));
-	scsi_cmd.op_code = PREVENT_ALLOW;
-	scsi_cmd.how=type;
-	return (st_scsi_cmd(unit,
-			&scsi_cmd,
-			sizeof(scsi_cmd),
-			0,
-			0,
-			5000,
-			NULL,
-			flags));
-}
-/*******************************************************\
-*  Rewind the device					*
-\*******************************************************/
-st_rewind(unit,immed,flags)
-int	unit,immed,flags;
+/*
+ *  Rewind the device
+ */
+errval 
+st_rewind(unit, immed, flags)
+	u_int32 unit, flags;
+	boolean immed;
 {
-	struct	scsi_rewind	scsi_cmd;
-	struct	st_data *st = st_data[unit];
-	int	error, nmarks;
+	struct scsi_rewind scsi_cmd;
+	struct st_data *st = st_data[unit];
+	errval  error;
+	int32   nmarks;
 
 	error = st_chkeod(unit, FALSE, &nmarks, flags);
-	if (error != ESUCCESS) return(error);
+	if (error != ESUCCESS)
+		return (error);
 	st->flags &= ~ST_PER_ACTION;
-	st->flags |= ST_AT_BOM;
 	bzero(&scsi_cmd, sizeof(scsi_cmd));
 	scsi_cmd.op_code = REWIND;
 	scsi_cmd.byte2 = immed ? SR_IMMED : 0;
-	return (st_scsi_cmd(unit,
-			&scsi_cmd,
-			sizeof(scsi_cmd),
-			0,
-			0,
-			immed?5000:300000, /* 5 sec or 5 min */
-			NULL,
-			flags));
-}
-
-/***************************************************************\
-* ststart looks to see if there is a buf waiting for the device	*
-* and that the device is not already busy. If both are true,	*
-* It deques the buf and creates a scsi command to perform the	*
-* transfer in the buf. The transfer request will call st_done	*
-* on completion, which will in turn call this routine again	*
-* so that the next queued transfer is performed.		*
-* The bufs are queued by the strategy routine (ststrategy)	*
-*								*
-* This routine is also called after other non-queued requests	*
-* have been made of the scsi driver, to ensure that the queue	*
-* continues to be drained.					*
-\***************************************************************/
-/* ststart() is called at splbio */
-ststart(unit)
-{
-	int			drivecount;
-	register struct buf	*bp = 0;
-	register struct buf	*dp;
-	struct	scsi_rw_tape	cmd;
-	int			blkno, nblk;
-	struct	st_data 	*st = st_data[unit];
-	int			flags;
-
-
-
-#ifdef	STDEBUG
-	if(scsi_debug & PRINTROUTINES) printf("ststart%d ",unit);
-#endif	/*STDEBUG*/
-	/*******************************************************\
-	* See if there is a buf to do and we are not already	*
-	* doing one						*
-	\*******************************************************/
-	if(st->scsi_xfer.flags & INUSE)
-	{
-		return;    /* unit already underway */
-	}
-trynext:
-	if(st->xfer_block_wait) /* a special awaits, let it proceed first */
-	{
-		wakeup(&(st->xfer_block_wait));
-		return;
-	}
-
-	if ((bp = st->buf_queue) == NULL)
-	{
-		return;	/* no work to bother with */
-	}
-	st->buf_queue = bp->b_actf;
-
-
-
-	/*******************************************************\
-	* only FIXEDBLOCK devices have pending operations	*
-	\*******************************************************/
-	if(st->flags & ST_FIXEDBLOCKS)
-	{
-		/*******************************************************\
-		*  If we are at a filemark but have not reported it yet	*
-		* then we should report it now				*
-		\*******************************************************/
-		if(st->flags & ST_AT_FILEMARK)
-		{
-			if ((bp->b_flags & B_READ) == B_WRITE)
-			{
-				/***************************************\
-				* Handling of ST_AT_FILEMARK in		*
-				* st_space will fill in the right file	*
-				* mark count.				*
-				\***************************************/
-				if (st_space(unit, 0, SP_FILEMARKS, 0) !=
-				    ESUCCESS) goto badnews;
-			}
-			else
-			{
-				bp->b_resid = bp->b_bcount;
-				bp->b_error = 0;
-				bp->b_flags &= ~B_ERROR;
-				st->flags &= ~ST_AT_FILEMARK;
-				biodone(bp);
-				goto trynext;
-			}
-		}
-		/*******************************************************\
-		*  If we are at EIO (e.g. EOM) but have not reported it	*
-		* yet then we should report it now			*
-		\*******************************************************/
-		if(st->flags & ST_EIO_PENDING)
-		{
-			bp->b_resid = bp->b_bcount;
-			bp->b_error = EIO;
-			bp->b_flags |= B_ERROR;
-			st->flags &= ~ST_EIO_PENDING;
-			biodone(bp);
-			goto trynext;
-		}
-	}
-	/*******************************************************\
-	*  Fill out the scsi command				*
-	\*******************************************************/
-	bzero(&cmd, sizeof(cmd));
-	if((bp->b_flags & B_READ) == B_WRITE)
-	{
-		cmd.op_code = WRITE_COMMAND_TAPE;
-		st->flags &= ~ST_FM_WRITTEN;
-		st->flags |= ST_WRITTEN;
-		flags = SCSI_DATA_OUT;
-	}
-	else
-	{
-		cmd.op_code = READ_COMMAND_TAPE;
-		flags = SCSI_DATA_IN;
-	}
-
-	/*******************************************************\
-	* Handle "fixed-block-mode" tape drives by using the    *
-	* block count instead of the length.			*
-	\*******************************************************/
-	if(st->flags & ST_FIXEDBLOCKS)
-	{
-		cmd.byte2 |= SRWT_FIXED;
-		lto3b(bp->b_bcount/st->blksiz,cmd.len);
-	}
-	else
-	{
-		lto3b(bp->b_bcount,cmd.len);
-	}
-
-	/*******************************************************\
-	* go ask the adapter to do all this for us		*
-	\*******************************************************/
-	if (st_scsi_cmd(unit,
-			&cmd,
-			sizeof(cmd),
-			(u_char *)bp->b_un.b_addr,
-			bp->b_bcount,
-			100000,
-			bp,
-			flags | SCSI_NOSLEEP ) != SUCCESSFULLY_QUEUED)
-
-	{
-badnews:
-		printf("st%d: oops not queued\n",unit);
-		bp->b_flags |= B_ERROR;
-		bp->b_error = EIO;
-		biodone(bp);
-		return;
-	}
-	stqueues++;
+	return (scsi_scsi_cmd(st->sc_link,
+		(struct scsi_generic *) &scsi_cmd,
+		sizeof(scsi_cmd),
+		0,
+		0,
+		ST_RETRIES,
+		immed ? 5000 : 300000,	/* 5 sec or 5 min */
+		NULL,
+		flags));
 }
 
-/*******************************************************\
-* This routine is called by the scsi interrupt when	*
-* the transfer is complete.
-\*******************************************************/
-int	st_done(unit,xs)
-int	unit;
-struct	scsi_xfer	*xs;
-{
-	struct	buf		*bp;
-	int	retval;
-	struct	st_data	*st = st_data[unit];
-
-#ifdef	STDEBUG
-	if(scsi_debug & PRINTROUTINES) printf("st_done%d ",unit);
-#endif	/*STDEBUG*/
-#ifdef	PARANOID
-	if (! (xs->flags & INUSE))
-		panic("scsi_xfer not in use!");
-#endif	/*PARANOID*/
-	if((bp = xs->bp)== NULL)
-	{
-		wakeup(xs);
-		return;
-	}
-	switch(xs->error)
-	{
-	case	XS_NOERROR:
-		bp->b_flags &= ~B_ERROR;
-		bp->b_error = 0;
-		bp->b_resid = 0;
-		break;
-	case	XS_SENSE:
-		retval = (st_interpret_sense(unit,xs));
-		bp->b_resid = xs->resid; /* already multiplied by blksiz */
-		if(retval)
-		{
-			/***************************************\
-			* We have a real error, the bit should	*
-			* be set to indicate this. The return	*
-			* value will contain the unix error code*
-			* that the error interpretation routine	*
-			* thought was suitable, so pass this	*
-			* value back in the buf structure.	*
-			* Furthermore we return information	*
-			* saying that no data was transferred	*
-			* All status is now suspect		*
-			\***************************************/
-			bp->b_flags |= B_ERROR;
-			bp->b_error = retval;
-			bp->b_resid =  bp->b_bcount;
-			st->flags &= ~ST_PER_ACTION;
-		}
-		else
-		{
-		/***********************************************\
-		* The error interpretation code has declared	*
-		* that it wasn't a real error, or at least that	*
-		* we should be ignoring it if it was.		*
-		\***********************************************/
-		    if(xs->resid == 0)
-		    {
-			/***************************************\
-			* we apparently had a corrected error	*
-			* or something.				*
-			* pretend the error never happenned	*
-			\***************************************/
-			bp->b_flags &= ~B_ERROR;
-			bp->b_error = 0;
-			break;
-		    }
-		    if ( xs->resid != xs->datalen )
-		    {
-			/***************************************\
-			* Here we have the tricky part..	*
-			* We successfully read less data than	*
-			* we requested. (but not 0)		*
-			*------for variable blocksize tapes:----*
-			* UNDER 386BSD:				*
-			* We should legitimatly have the error	*
-			* bit set, with the error value set to 	*
-			* zero.. This is to indicate to the	*
-			* physio code that while we didn't get	*
-			* as much information as was requested,	*
-			* we did reach the end of the record	*
-			* and so physio should not call us	*
-			* again for more data... we have it all	*
-			* SO SET THE ERROR BIT!			*
-			*					*
-			* UNDER NetBSD:				*
-			* To indicate the same as above, we	*
-			* need only have a non 0 resid that is	*
-			* less than the b_bcount, but the	*
-			* ERROR BIT MUST BE CLEAR! (sigh) 	*
-			*					*
-			*-------for fixed blocksize device------*
-			* We read some successful records	*
-			* before hitting the EOF or EOT. These	*
-			* must be passed to the user, before we	*
-			* report the EOx.  We will report the	*
-			* EOx NEXT time.			*
-			\***************************************/
-#ifdef	NETBSD 
-			bp->b_flags &= ~B_ERROR;
+#ifdef	NETBSD
+#define	SIGNAL_SHORT_READ
 #else
-			bp->b_flags |= B_ERROR;
-#endif	
-			bp->b_error = 0;
-			xs->error = XS_NOERROR;
-			break;
-		    }
-		    else
-		    {
-			/***************************************\
-			* We have come out of the error handler	*
-			* with no error code.  We have also not	*
-			* transferred any data (would have gone	*
-			* to the previous clause).		*
-			* This must be an EOF			*
-			*  Any caller request to read no	*
-			* data would have been short-circuited	*
-			* at st_read or ststrategy.		*
-			*					*
-			* At least all o/s agree that:		*
-			* 0 bytes read with no error is EOF	*
-			\***************************************/
-
-			bp->b_error = 0;
-			bp->b_flags &= ~B_ERROR;
-			st->flags &= ~ST_AT_FILEMARK;
-			break;
-		    }
-		}
-		break;
-
-	case    XS_TIMEOUT:
-		printf("st%d: timeout\n",unit);
-
-	case    XS_BUSY:        /* should retry */ /* how? */
-		/************************************************/
-		/* SHOULD put buf back at head of queue         */
-		/* and decrement retry count in (*xs)           */
-		/* HOWEVER, this should work as a kludge        */
-		/************************************************/
-		if(xs->retries--)
-		{
-			xs->flags &= ~ITSDONE;
-			xs->error = XS_NOERROR;
-			if ( (*(st->sc_sw->scsi_cmd))(xs)
-				== SUCCESSFULLY_QUEUED)
-			{       /* don't wake the job, ok? */
-				return;
-			}
-			printf("st%d: device busy\n",unit);
-			xs->flags |= ITSDONE;
-		}
-
-	case	XS_DRIVER_STUFFUP:
-		bp->b_flags |= B_ERROR;
-		bp->b_error = EIO;
-		break;
-	default:
-		printf("st%d: unknown error category from scsi driver\n"
-			,unit);
-	}	
-	biodone(bp);
-	xs->flags = 0;	/* no longer in use */
-	ststart(unit);		/* If there's another waiting.. do it */
-}
-
-
+#define	SIGNAL_SHORT_READ bp->b_flags |= B_ERROR;
+#endif
 
-/*******************************************************\
-* ask the scsi driver to perform a command for us.	*
-* Call it through the switch table, and tell it which	*
-* sub-unit we want, and what target and lu we wish to	*
-* talk to. Also tell it where to find the command	*
-* how long int is.					*
-* Also tell it where to read/write the data, and how	*
-* long the data is supposed to be			*
-\*******************************************************/
-int	st_scsi_cmd(unit,scsi_cmd,cmdlen,data_addr,datalen,timeout,bp,flags)
-
-int	unit,flags;
-struct	scsi_generic *scsi_cmd;
-int	cmdlen;
-int	timeout;
-u_char	*data_addr;
-struct	buf *bp;
-int	datalen;
+/*
+ * Look at the returned sense and act on the error and detirmine
+ * The unix error number to pass back... (0 = report no error)
+ *                            (-1 = continue processing)
+ */
+errval 
+st_interpret_sense(xs)
+	struct scsi_xfer *xs;
 {
-	struct	scsi_xfer *xs;
-	int	retval;
-	int	s;
-	struct	st_data *st = st_data[unit];
-
-#ifdef	STDEBUG
-	if(scsi_debug & PRINTROUTINES) printf("\nst_scsi_cmd%d ",unit);
-#endif	/*STDEBUG*/
-#ifdef	PARANOID
-	if(st->sc_sw == NULL)	/* If we have no scsi driver */
-	{
-		printf("st%d: not set up\n",unit);
-		return(EINVAL);
+	struct scsi_link *sc_link = xs->sc_link;
+	struct scsi_sense_data *sense = &(xs->sense);
+	boolean silent = xs->flags & SCSI_SILENT;
+	struct buf *bp = xs->bp;
+	u_int32 unit = sc_link->dev_unit;
+	struct st_data *st = st_data[unit];
+	u_int32 key;
+	int32   info;
+
+	/*
+	 * Get the sense fields and work out what code
+	 */
+	if (sense->error_code & SSD_ERRCODE_VALID) {
+		info = ntohl(*((int32 *) sense->ext.extended.info));
+	} else {
+		info = xs->datalen;	/* bad choice if fixed blocks */
 	}
-#endif	/*PARANOID*/
-
-	xs = &(st->scsi_xfer);
-	if(!(flags & SCSI_NOMASK))
-		s = splbio();
-	st->xfer_block_wait++;	/* there is someone waiting */
-	while (xs->flags & INUSE)
-	{
-		if(flags & SCSI_NOSLEEP)
-			return EBUSY;
-		sleep(&(st->xfer_block_wait),PRIBIO+1);
+	if ((sense->error_code & SSD_ERRCODE) != 0x70) {
+		return (-1);	/* let the generic code handle it */
 	}
-	st->xfer_block_wait--;
-	xs->flags = INUSE;
-	if(!(flags & SCSI_NOMASK))
-		splx(s);
-
-	/*******************************************************\
-	* Fill out the scsi_xfer structure			*
-	\*******************************************************/
-	xs->flags	|=	flags;
-	xs->adapter	=	st->ctlr;
-	xs->targ	=	st->targ;
-	xs->lu		=	st->lu;
-	xs->retries	=	bp?0:ST_RETRIES;/*can't retry on IO*/
-	xs->timeout	=	timeout;
-	xs->cmd		=	scsi_cmd;
-	xs->cmdlen	=	cmdlen;
-	xs->data	=	data_addr;
-	xs->datalen	=	datalen;
-	xs->resid	=	datalen;
-	xs->when_done	=	st_done;
-	xs->done_arg	=	unit;
-	xs->done_arg2	=	(int)xs;
-	xs->bp		=	bp;
-retry:	xs->error	=	XS_NOERROR;
-
-	/***********************************************\
-	* Ask the adapter to do the command for us	*
-	\***********************************************/
-	retval = (*(st->sc_sw->scsi_cmd))(xs);
-
-	/***********************************************\
-	* IO operations are handled differently..	*
-	* Physio does the sleep, and error handling is	*
-	* Done in st_done at interrupt time		*
-	\***********************************************/
-	if(bp) return retval;	
-
-	/***********************************************\
-	* Wait for the result if queued, or handle the	*
-	* error if it was rejected..			*
-	\***********************************************/
-	switch(retval)
-	{
-	case	SUCCESSFULLY_QUEUED:
-		s = splbio();
-		while(!(xs->flags & ITSDONE))
-			sleep(xs,PRIBIO+1);
-		splx(s);
-		/*******************************\
-		* finished.. check for failure	*
-		* Fall through......		*
-		\*******************************/
-	case	HAD_ERROR:
-	case	COMPLETE:
-		switch(xs->error)
-		{
-		case	XS_NOERROR:
-			retval = ESUCCESS;
-			break;
-		case	XS_SENSE:
-			retval = (st_interpret_sense(unit,xs));
-			/* only useful for reads *//* why did I say that?*/
-			if (retval)
-			{ /* error... don't care about filemarks */
-				st->flags &= ~ST_PER_ACTION;
-			}
-			else
-			{
-				xs->error = XS_NOERROR;
-				retval = ESUCCESS;
-			}
-			break;
-		case	XS_DRIVER_STUFFUP:
-			retval = EIO;
-			break;
-		case    XS_BUSY:
-			/* should sleep 1 sec here */
-		case    XS_TIMEOUT:
-			if(xs->retries-- )
-			{
-				xs->flags &= ~ITSDONE;
-				goto retry;
+	if (st->flags & ST_FIXEDBLOCKS) {
+		xs->resid = info * st->blksiz;
+		if (sense->ext.extended.flags & SSD_EOM) {
+			st->flags |= ST_EIO_PENDING;
+			if (bp) {
+				bp->b_resid = xs->resid;
+				SIGNAL_SHORT_READ
 			}
-			retval = EIO;
-			break;
-		default:
-			retval = EIO;
-			printf("st%d: unknown error category from scsi driver\n"
-				,unit);
-			break;
-		}	
-		break;
-	case 	TRY_AGAIN_LATER:
-		if(xs->retries-- )
-		{
-			xs->flags &= ~ITSDONE;
-			/* should delay here */
-			goto retry;
 		}
-		retval = EIO;
-		break;
-	default:
-		retval = EIO;
-	}
-	xs->flags = 0;	/* it's free! */
-	ststart(unit);
-	return(retval);
-}
-/***************************************************************\
-* Look at the returned sense and act on the error and detirmine	*
-* The unix error number to pass back... (0 = report no error)	*
-\***************************************************************/
-
-int	st_interpret_sense(unit,xs)
-int	unit;
-struct	scsi_xfer	*xs;
-{
-	struct	scsi_sense_data *sense;
-	int	key;
-	int	silent = xs->flags & SCSI_SILENT;
-	struct	st_data	*st = st_data[unit];
-	int	info;
-	static char *error_mes[] = {		"soft error (corrected)",
-		"not ready",			"medium error",
-		"non-media hardware failure",	"illegal request",
-		"unit attention",		"tape is write-protected",
-		"no data found",		"vendor unique",
-		"copy aborted",			"command aborted",
-		"search returned equal",	"volume overflow",
-		"verify miscompare",		"unknown error key"
-	};
-
-	/***************************************************************\
-	* If errors are ok, report a success				*
-	\***************************************************************/
-	if(xs->flags & SCSI_ERR_OK) return(ESUCCESS);
-
-	/***************************************************************\
-	* Get the sense fields and work out what code			*
-	\***************************************************************/
-	sense = &(xs->sense);
-#ifdef	STDEBUG
-	if(st_debug)
-	{
-		int count = 0;
-		printf("code%x valid%x\n"
-				,sense->error_code & SSD_ERRCODE
-				,sense->error_code & SSD_ERRCODE_VALID ? 1 : 0);
-		printf("seg%x key%x ili%x eom%x fmark%x\n"
-				,sense->ext.extended.segment
-				,sense->ext.extended.flags & SSD_KEY
-				,sense->ext.extended.flags & SSD_ILI ? 1 : 0
-				,sense->ext.extended.flags & SSD_EOM ? 1 : 0
-				,sense->ext.extended.flags & SSD_FILEMARK ? 1 : 0);
-		printf("info: %x %x %x %x followed by %d extra bytes\n"
-				,sense->ext.extended.info[0]
-				,sense->ext.extended.info[1]
-				,sense->ext.extended.info[2]
-				,sense->ext.extended.info[3]
-				,sense->ext.extended.extra_len);
-		printf("extra: ");
-		while(count < sense->ext.extended.extra_len)
-		{
-			printf ("%x ",sense->ext.extended.extra_bytes[count++]);
+		if (sense->ext.extended.flags & SSD_FILEMARK) {
+			st->flags |= ST_AT_FILEMARK;
+			if (bp) {
+				bp->b_resid = xs->resid;
+				SIGNAL_SHORT_READ
+			}
 		}
-		printf("\n");
-	}
-#endif	/*STDEBUG*/
-	if(sense->error_code & SSD_ERRCODE_VALID)
-	{
-		info = ntohl(*((long *)sense->ext.extended.info));
-	}
-	else
-	{
-		info = xs->datalen; /* bad choice if fixed blocks */
-	}
-
-
-	switch(sense->error_code & SSD_ERRCODE)
-	{
-	/***************************************************************\
-	* If it's code 70, use the extended stuff and interpret the key	*
-	\***************************************************************/
-	case 0x70:
-		if(st->flags & ST_FIXEDBLOCKS)
-		{
-			xs->resid = info * st->blksiz;
-			if(sense->ext.extended.flags & SSD_EOM)
-			{
-				st->flags |= ST_EIO_PENDING;
+		if (sense->ext.extended.flags & SSD_ILI) {
+			st->flags |= ST_EIO_PENDING;
+			if (bp) {
+				bp->b_resid = xs->resid;
+				SIGNAL_SHORT_READ
 			}
-			if(sense->ext.extended.flags & SSD_FILEMARK)
-			{
-				st->flags |= ST_AT_FILEMARK;
+			if (sense->error_code & SSD_ERRCODE_VALID &&
+			    !silent)
+				printf("st%d: block wrong size"
+				    ", %d blocks residual\n", unit
+				    ,info);
+
+			/*
+			 * This quirk code helps the drive read
+			 * the first tape block, regardless of
+			 * format.  That is required for these
+			 * drives to return proper MODE SENSE
+			 * information.
+			 */
+			if ((st->quirks & ST_Q_SNS_HLP) &&
+			    !(sc_link->flags & SDEV_MEDIA_LOADED)) {
+				st->blksiz -= 512;
 			}
-			if(sense->ext.extended.flags & SSD_ILI)
-			{
-				st->flags |= ST_EIO_PENDING;
-				if (sense->error_code & SSD_ERRCODE_VALID &&
-				    !silent)
-					printf("st%d: %d-byte block wrong size"
-					    "\n", unit, xs->datalen - info);
-
-				/***************************************\
-				* This quirk code helps the drive read	*
-				* the first tape block, regardless of	*
-				* format.  That is required for these	*
-				* drives to return proper MODE SENSE	*
-				* information.				*
-				\***************************************/
-				if ((st->quirks & ST_Q_SNS_HLP) &&
-				    !(st->flags & ST_INFO_VALID))
-				{
-					st->blksiz -= 512;
-				}
+		}
+		/*
+		 * If no data was tranfered, do it immediatly
+		 */
+		if (xs->resid >= xs->datalen) {
+			if (st->flags & ST_EIO_PENDING) {
+				return EIO;
 			}
-			/***********************************************\
-			* If no data was tranfered, do it immediatly	*
-			\***********************************************/
-			if(xs->resid >= xs->datalen)
-			{
-				if(st->flags & ST_EIO_PENDING) 
-				{
-					return EIO;
-				}
-				if(st->flags & ST_AT_FILEMARK) 
-				{
-					return 0;
+			if (st->flags & ST_AT_FILEMARK) {
+				if (bp) {
+					bp->b_resid = xs->resid;
+					SIGNAL_SHORT_READ
 				}
+				return 0;
 			}
 		}
-		else
-		{
-			xs->resid = xs->datalen; /* to be sure */
-			if(sense->ext.extended.flags & SSD_EOM)
-			{
-				return(EIO);
+	} else {		/* must be variable mode */
+		xs->resid = xs->datalen;	/* to be sure */
+		if (sense->ext.extended.flags & SSD_EOM) {
+			return (EIO);
+		}
+		if (sense->ext.extended.flags & SSD_FILEMARK) {
+			if (bp)
+				bp->b_resid = bp->b_bcount;
+			return 0;
+		}
+		if (sense->ext.extended.flags & SSD_ILI) {
+			if (info < 0) {
+				/*
+				 * the record was bigger than the read
+				 */
+				if (!silent)
+					printf("st%d: %d-byte record "
+					    "too big\n", unit,
+					    xs->datalen - info);
+				return (EIO);
 			}
-			if(sense->ext.extended.flags & SSD_FILEMARK)
-			{
-				return 0;
+			xs->resid = info;
+			if (bp) {
+				bp->b_resid = info;
+				SIGNAL_SHORT_READ
 			}
-			if(sense->ext.extended.flags & SSD_ILI)
-			{
-				if(info < 0)
-				/***************************************\
-				* the record was bigger than the read	*
-				\***************************************/
-				{
-					if (!silent)
-						printf("st%d: %d-byte record "
-						    "too big\n", unit,
-						    xs->datalen - info);
-					return(EIO);
-				}
-				xs->resid = info;
+		}
+	}
+	key = sense->ext.extended.flags & SSD_KEY;
+
+	if (key == 0x8) {
+		/*
+		 * This quirk code helps the drive read the
+		 * first tape block, regardless of format.  That
+		 * is required for these drives to return proper
+		 * MODE SENSE information.
+		 */
+		if ((st->quirks & ST_Q_SNS_HLP) &&
+		    !(sc_link->flags & SDEV_MEDIA_LOADED)) {	/* still starting */
+			st->blksiz -= 512;
+		} else if (!(st->flags & (ST_2FM_AT_EOD | ST_BLANK_READ))) {
+			st->flags |= ST_BLANK_READ;
+			xs->resid = xs->datalen;
+			if (bp) {
+				bp->b_resid = xs->resid;
+				/*return an EOF */
 			}
-		}/* there may be some other error. check the rest */
+			return (ESUCCESS);
+		}
+	}
+	return (-1);		/* let the default/generic handler handle it */
+}
 
-		key=sense->ext.extended.flags & SSD_KEY;
+/*
+ * The quirk here is that the drive returns some value to st_mode_sense
+ * incorrectly until the tape has actually passed by the head.
+ *
+ * The method is to set the drive to large fixed-block state (user-specified
+ * density and 1024-byte blocks), then read and rewind to get it to sense the
+ * tape.  If that doesn't work, try 512-byte fixed blocks.  If that doesn't
+ * work, as a last resort, try variable- length blocks.  The result will be
+ * the ability to do an accurate st_mode_sense.
+ *
+ * We know we can do a rewind because we just did a load, which implies rewind.
+ * Rewind seems preferable to space backward if we have a virgin tape.
+ *
+ * The rest of the code for this quirk is in ILI processing and BLANK CHECK
+ * error processing, both part of st_interpret_sense.
+ */
+errval
+st_touch_tape(unit)
+	u_int32	unit;
+{
+	struct st_data *st = st_data[unit];
+	char   *buf;
+	u_int32 readsiz;
+	errval  errno;
 
-		if (!silent && key > 0 && (key != 0x8 ||
-		    st->flags & (ST_2FM_AT_EOD | ST_BLANK_READ)))
-		{
-			printf("st%d: %s", unit, error_mes[key - 1]);
-			if(sense->error_code & SSD_ERRCODE_VALID)
-			{
-				switch (key)
-				{
-				case	0x2:		/* NOT READY */
-				case	0x5:		/* ILLEGAL REQUEST */
-				case	0x6:		/* UNIT ATTENTION */
-				case	0x7:		/* DATA PROTECT */
-					break;
-				case	0x8:		/* BLANK CHECK */
-			   		printf(", requested size: %d (decimal)",
-					    info);
-					break;
-				default:
-			   		printf(", info = %d (decimal)", info);
-				}
-			}
-			printf("\n");
-		}
+	buf = malloc(1024, M_TEMP, M_NOWAIT);
+	if (!buf)
+		return (ENOMEM);
 
-		switch (key)
-		{
-		case	0x0:				/* NO SENSE */
-		case	0x1:				/* RECOVERED ERROR */
-			if(xs->resid == xs->datalen) xs->resid = 0;
-		case	0xc:				/* EQUAL */
-			return(ESUCCESS);
-		case	0x2:				/* NOT READY */
-			return(ENODEV);
-		case	0x5:				/* ILLEGAL REQUEST */
-			return(EINVAL);
-		case	0x6:				/* UNIT ATTENTION */
-			st->flags &= ~ST_PER_MEDIA;
-			if (st->flags & ST_OPEN) /* TEMP!!!! */
-				return(EIO);
-			else
-				return(ESUCCESS);
-		case	0x7:				/* DATA PROTECT */
-			return(EACCES);
-		case	0xd:				/* VOLUME OVERFLOW */
-			return(ENOSPC);
-		case	0x8:				/* BLANK CHECK */
-			/***********************************************\
-			* This quirk code helps the drive read the	*
-			* first tape block, regardless of format.  That	*
-			* is required for these drives to return proper	*
-			* MODE SENSE information.			*
-			\***********************************************/
-			if ((st->quirks & ST_Q_SNS_HLP) &&
-			    !(st->flags & ST_INFO_VALID))
-			{
-				st->blksiz -= 512;
-			}
-			else if (!(st->flags & (ST_2FM_AT_EOD | ST_BLANK_READ)))
-			{
-				st->flags |= ST_BLANK_READ;
-				xs->resid = xs->datalen;
-				return(ESUCCESS);
-			}
+	if (errno = st_mode_sense(unit, 0)) {
+		goto bad;
+	}
+	st->blksiz = 1024;
+	do {
+		switch (st->blksiz) {
+		case 512:
+		case 1024:
+			readsiz = st->blksiz;
+			st->flags |= ST_FIXEDBLOCKS;
+			break;
 		default:
-			return(EIO);
+			readsiz = 1;
+			st->flags &= ~ST_FIXEDBLOCKS;
+		} if (errno = st_mode_select(unit, 0)) {
+			goto bad;
 		}
-	/***************************************************************\
-	* If it's NOT code 70, just report it.				*
-	\***************************************************************/
-	default:
-		if (!silent)
-		{
-			printf("st%d: error code %d", unit,
-				sense->error_code & SSD_ERRCODE);
-			if(sense->error_code & SSD_ERRCODE_VALID)
-			{
-				printf(" at block no. %d (decimal)",
-					(sense->ext.unextended.blockhi << 16) +
-					(sense->ext.unextended.blockmed << 8) +
-					sense->ext.unextended.blocklow);
-			}
-			printf("\n");
+		st_read(unit, buf, readsiz, SCSI_SILENT);
+		if (errno = st_rewind(unit, FALSE, 0)) {
+bad:			free(buf, M_TEMP);
+			return (errno);
 		}
-		return(EIO);
-	}
+	} while (readsiz != 1 && readsiz > st->blksiz);
+	free(buf, M_TEMP);
+	return 0;
 }