been relocated to run in the 64k segment at 0x10000 with the stack at
the top of this segment. This corrects the problems machines with 512K
base memory had booting.
2. startprog routing rewritten to convert the BOOTSEG ss to a KERNELSEG
ss, this eliminated the last of the >512K memory references. Additional
cleanup in here included a better way to copy the arguments to the
kernel stack.
3. Elimination of argv and esym cruft saved a few bytes.
4. Only need to truncate the head.a_entry to a meg boundary once intead
of every time we used it! [Saving more bytes].
5. Addition of version 1 bootinfo structure support. These boot blocks
pass the kernel name in to the kernel now.
6. Removed historical comments about MACH argv stuff, as it is useless now.
1) Fixed up some header locations
2) Replaced list of boot files with /kernel
3) Changed disklabel use in Makefile to conform to 4.4
4) Added size command in Makefile to get close estimate of bootblock
sizes. Total size of text and data must be below 64K, slightly
overestimated since a.out header subsequently gets stripped.
5) Various buffer sizes are set to 8192 bytes in sys.c. In 4.4 MAXBSIZE
is set to 64K which is too big for the bootblocks to deal with.
Submitted by: Paul Richards
>From: bde@kralizec.zeta.org.au (Bruce Evans)
Subject: cache botch in bootstrap
Date: Sun, 20 Feb 94 18:14:35 +1100
The cache in the bootstrap loader didn't allow for the device changing.
This caused surprisingly little trouble - the cache is only for a single
track (or part of a track), and the first access to a new device is
always for an early sector, so there is no problem unless the last access
to the old device was for an early sector. I saw the problem on a system
with BSD on wd1 and no label on wd0. Everything worked if the the device
name wd(1,a) was specified before the default of wd(0,a) was tried, but
when the default was tried, it failed on the first sector because there
was no label, and then the first sector on wd0 was always used instead
of the first sector on wd1, so there was apparently no label on wd1
either.
Bruce
now reads:
printf("use hd(1,a)/386bsd to boot sd0 when wd0 is also installed\n");
I know the person wanted more explination, but there is little room in
the boot blocks for verbose text!
is so often reported as an error condition when it is not. We print the
size of things so for those who want to know if this happened they can
figure it out from the size information that is printed.
