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diff --git a/share/doc/handbook/memoryuse.sgml b/share/doc/handbook/memoryuse.sgml deleted file mode 100644 index 9e62d22..0000000 --- a/share/doc/handbook/memoryuse.sgml +++ /dev/null @@ -1,50 +0,0 @@ -<!-- $Id$ --> -<!-- The FreeBSD Documentation Project --> - -<sect><heading>PC memory utilization<label id="memoryuse"></heading> - -<p><em>Contributed by &a.joerg;.<newline> - 16 Apr 1995.</em> - -<em>A short description of how FreeBSD uses the memory on the i386 -platform</em> - -The boot sector will be loaded at <tt>0:0x7c00</tt>, and relocates itself -immediately to <tt>0x7c0:0</tt>. (This is nothing magic, just an adjustment -for the <tt>%cs</tt> selector, done by an <tt>ljmp</tt>.) - -It then loads the first 15 sectors at <tt>0x10000</tt> (segment BOOTSEG in the -biosboot Makefile), and sets up the stack to work below <tt>0x1fff0</tt>. -After this, it jumps to the entry of boot2 within that code. I.e., it -jumps over itself and the (dummy) partition table, and it is going to -adjust the %cs selector---we are still in 16-bit mode there. - -boot2 asks for the boot file, and examines the <tt>a.out</tt> header. It masks -the file entry point (usually <tt>0xf0100000</tt>) by <tt>0x00ffffff</tt>, and loads the -file there. Hence the usual load point is 1 MB (<tt>0x00100000</tt>). During -load, the boot code toggles back and forth between real and protected -mode, to use the BIOS in real mode. - -The boot code itself uses segment selectors <tt>0x18</tt> and <tt>0x20</tt> for <tt>%cs</tt> and -<tt>%ds/%es</tt> in protected mode, and <tt>0x28</tt> to jump back into real mode. The -kernel is finally started with <tt>%cs</tt> <tt>0x08</tt> and <tt>%ds/%es/%ss</tt> <tt>0x10</tt>, which -refer to dummy descriptors covering the entire address space. - -The kernel will be started at its load point. Since it has been linked -for another (high) address, it will have to execute PIC until the page -table and page directory stuff is setup properly, at which point -paging will be enabled and the kernel will finally run at the address -for which it was linked. - - -<em>Contributed by &a.davidg;.<newline> - 16 Apr 1995.</em> - -The physical pages immediately following the kernel BSS contain -proc0's page directory, page tables, and upages. Some time later -when the VM system is initialized, the physical memory between -<tt>0x1000-0x9ffff</tt> and the physical memory after the kernel -(text+data+bss+proc0 stuff+other misc) is made available in the -form of general VM pages and added to the global free page list. - - |
