diff options
Diffstat (limited to 'sbin/i386/nextboot/nextboot.8')
| -rw-r--r-- | sbin/i386/nextboot/nextboot.8 | 33 |
1 files changed, 22 insertions, 11 deletions
diff --git a/sbin/i386/nextboot/nextboot.8 b/sbin/i386/nextboot/nextboot.8 index 75ad6d3..bd73481 100644 --- a/sbin/i386/nextboot/nextboot.8 +++ b/sbin/i386/nextboot/nextboot.8 @@ -21,9 +21,11 @@ program controls the actions of the boot blocks at the time of the next boot. If compiled with the correct option, the boot blocks will check the nameblock for a magic number and a -default name to use for booting. If compiled to do so they will also +default name to use for booting. +If compiled to do so they will also delete the name from the block, ensuring that if the boot should fail, -then it will not be tried again. It is the job of +then it will not be tried again. +It is the job of .Pa /etc/rc to use .Nm @@ -36,7 +38,8 @@ on the disk. The following options are available: .Bl -tag -width indent .It Fl b -Is used for bootstrapping (initially configuring) the nameblock. Without +Is used for bootstrapping (initially configuring) the nameblock. +Without this, .Nm will refuse to write to a block that does not already contain the magic @@ -57,15 +60,19 @@ flags are mutually exclusive. .Sh DESCRIPTION .Nm Nextboot first checks that the disk has an fdisk table and checks that none of the -partitions defined in that table include the nameblock. If the name block is +partitions defined in that table include the nameblock. +If the name block is shown to be unused, it will install the bootstrings given as arguments, one after the other, each preceded by a small magic number, and NULL -terminated. The end of the list of strings is delimited by a sequence of -0xff bytes. If the boot blocks are compiled to write back the nameblock +terminated. +The end of the list of strings is delimited by a sequence of +0xff bytes. +If the boot blocks are compiled to write back the nameblock after each boot, it will zero out the supplied names as it uses them, one per boot, until it reaches the 0xff, at which time it will revert to the compiled in -boot string. At this time the nameblock will contain only zeroed out names. +boot string. +At this time the nameblock will contain only zeroed out names. .Pp An example of usage might be: .Bd -literal @@ -78,12 +85,15 @@ If for any reason this failed, the next boot attempt would boot the kernel .Pa /kernel.old off the IDE drive. (Assuming the write-back option were enabled) If this -in turn failed. The compiled in default would be used. +in turn failed. +The compiled in default would be used. .Pp If the write-back feature is disabled, the nextboot program is a convenient way -to change the default boot string. Note, that should the file specified in +to change the default boot string. +Note, that should the file specified in the nameblock be non-existent, then the name compiled into the boot blocks -will be used for the boot rather than the next name in the nameblock. The +will be used for the boot rather than the next name in the nameblock. +The nameblock is only consulted .Em once per boot. @@ -96,7 +106,8 @@ This program works only in conjunction with the legacy boot code. .Pp The entire program should be made more user-friendly. The option of whether to write back or not should be stored on the -disk and not a compile time option. I want to rethink this at some +disk and not a compile time option. +I want to rethink this at some later stage to make it co-exist with disks that do not have a fdisk partitioning table (i.e. purely disklabel'd systems). .Pp |
