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Fixed some speling, punctuation.. and spac ing errors.

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bde 1996-07-12 05:17:37 +00:00
parent e75f9a15ea
commit 48992969bb
2 changed files with 19 additions and 19 deletions
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4
sys/i386/boot/biosboot/Makefile
View File

@ -1,4 +1,4 @@
# $Id: Makefile,v 1.40 1996/05/11 04:27:23 bde Exp $
# $Id: Makefile,v 1.41 1996/07/09 02:28:15 julian Exp $
#
PROG= boot
@ -21,7 +21,7 @@ CFLAGS+= -DBOOTSEG=${BOOTSEG} -DBOOTSTACK=${BOOTSTACK}
#CFLAGS+= -DFORCE_COMCONSOLE
# Enable code to take the default boot string from a fixed location on the
# disk.. see nextboot(8) and README.386BSD for more info
# disk. See nextboot(8) and README.386BSD for more info.
#CFLAGS+= -DNAMEBLOCK
#CFLAGS+= -DNAMEBLOCK_WRITEBACK

34
sys/i386/boot/biosboot/README.386BSD
View File

@ -1,5 +1,5 @@
Note: all my origianl references to 386BSD also refer to freeBSD and NetBSD
which in some ways derived from 386BSD. --julian@freebsd.org
Note: all my original references to 386BSD also refer to freeBSD and NetBSD
which in some ways are derived from 386BSD. --julian@freebsd.org
This Boot code is different from the original boot code that came with
386BSD in that it uses the BIOS to load the kernel and to provide all i/o
@ -18,12 +18,12 @@ following operations occur:
1/ the BIOS loads the first block of the disk (called the Master Boot Record
or MBR) and if it has the correct magic numbers, jumps into it:
2/ The MBR code, looks at the Partition table that is embedded within it,
2/ The MBR code, looks at the Partition table that is embedded within it,
to determine which is the partition to boot from. If you install the
boot manager when FreeBSD is first installed, it will also give you a nice
menu for switching between operating systems.
3/ The MBR will load the first record of the selected partition and
3/ The MBR will load the first record of the selected partition and
if it has (the same) magic numbers, jumps into it. In 386bsd this is the
first stage boot, (or boot1) it is represented in /usr/mdec by
wdboot, asboot and sdboot. If the disk has been set up without DOS partitioning
@ -39,17 +39,17 @@ at 0. This ensures that the same code can work whether or not
boot1 is at block 0.
4A/ IF the NAMEBLOCK option is compiled into the bootcode, then the
boot1 code will load and examine block1 (Usually unused) and
look for a default boot string to use later.. (if the corrct magic number
boot1 code will load and examine block1 (usually unused) and
look for a default boot string to use later (if the correct magic number
is present). If the option NAMEBLOCK_WRITEBACK is also defined, then
it will zero out that name after finding it, and write the block back,
having "used up" that name. The block may contain multiple different
boot strings which will be "used up" one after the other.. (one per boot)
boot strings which will be "used up" one after the other (one per boot)
They are set using the "nextboot" utility.
4B/ Using the information found in step 4, regarding the start position
of the BSD partition, boot1 will load the first 16 sectors of that partition,
to around 0x10000 (64k). and will jump into it at the appropriate entry point.
of the BSD partition, boot1 will load the first 16 sectors of that partition,
to around 0x10000 (64k) and will jump into it at the appropriate entry point.
Since boot1 and boot2 were compiled together as one file and then split
later, boot1 knows the exact position within boot2 of the entry point.
@ -64,14 +64,14 @@ actions then a default string will be used.
If the NAMEBLOCK option is used, then the default string may have been
loaded from block2. If none was found then a compiled in default will be used.
6/On finding the disklabel, on the disk th euser spacified, boot2 can find
6/On finding the disklabel, on the disk the user spacified, boot2 can find
the correct unix partition within the 386bsd partition, and using cutdown
filesystem code, look for the file to boot (e.g. 386bsd).
filesystem code, look for the file to boot (e.g., 386bsd).
7/ Boot2 loads this file starting at the location specified by the a.out header,
(see later) and leaps into it at the location specified in he header.
if the file does not exist or cannot be loaded, boot2 goes back to step 5.
if the file does not exist or cannot be loaded, boot2 goes back to step 5.
386bsd is now running and will hopefully start vm etc. and get to multi-user
mode.
@ -95,11 +95,11 @@ partition, and you can change it to a 386BSD partition later. If you use
no DOS partitioning, then the compiled in table in Boot1 will do just fine.
If you want to do it by hand remember that BIOS counts sectors starting at 1.
(cylinders and heads start at 0 (??))
(cylinders and heads start at 0 (??))
2/ you cannot overwrite the bottom 4k of ram until you have finished ALL
bios calls, as BIOS uses this area as scratch memory.
This is no longer really a probelm as we no-longer support loading the kernel
This is no longer really a problem as we no-longer support loading the kernel
at location 0.
3/ Since BIOS runs in REAL mode, and Boot2 runs in protected mode,
@ -109,10 +109,10 @@ back to protected mode on each return. Touch this at your peril.!
#########################################################################
In answering the prompt from Boot2:
you can,
1/ leave it alone.. it will boot the indicated file from the first
1/ leave it alone. It will boot the indicated file from the first
partition of the first drive seen by the BIOS (C:)
If the NAMEBLOCK option is in use, the default name might be taken from block1
(2nd block) on that drive. (the drive on which boot 1 was loaded).
(2nd block) on that drive (the drive on which boot 1 was loaded).
2/ enter only "-s" to boot the default to single user mode
@ -169,4 +169,4 @@ Before you do this ensure you have a booting floppy with correct
disktab and bootblock files on it so that if it doesn't work, you can
re-disklabel from the floppy.
$Id: README.386BSD,v 1.5 1996/07/05 19:55:02 julian Exp $
$Id: README.386BSD,v 1.6 1996/07/09 02:28:17 julian Exp $