This work has been sponsored by Plutotech International, Inc (who paid
the initial work), and interface business GmbH (where i did most of
the work). A big thanks also goes to Bruce Evans, for his continuing
help and answering my stupid questions.
The code is basically functioning, with the following caveats:
. Rock Ridge attributes are not yet supported.
. Only SCSI CD-ROMs are supported, since i fail to see any possibility
to determine the drive type using BIOS functions. (Even for hard disks,
this determination is done by a big hack only.)
. El Torito specifies a lot of crap and useless misfeatures, but crucial
things like the ability to figure out the CD TOC have been ``forgotten''.
Thus, if you wanna boot a multisession CD, you need to know at which CD
block your session starts, and need to speciffy it using the @ clause.
. None of the CD-ROM controllers i've seen so far implements the full
El Torito specification at all. Adaptec is probably the closest, but
they miss on non-emulation booting (which would be the most logical
choice for us). Thus, the current code bloats the 7.5 KB boot code
up to 1.44 MB, in order to fake a `floppy' image.
If you wanna use it, specify this file as the boot image on the
command-line of the mksiosfs command (option -b).
Caveat emptor: some versions of the Adaptec BIOS might even fail to
access the CD-ROM at all, using the BIOS functions. I think i've
notice this for ver 1.26, the code has been tested with ver 1.23.
The boot string is as follows:
[@sess-start] [filename] [-flags]
sess-start Extend # where the last session starts, measured in
CD-ROM blocks.
filename As usual, but the input is case-insensitive by now
(since we don't grok RR anyway).
flags As usual, but -C (use CDROM root f/s) is default, so
specifying -C will decactivate this option (which is
probably not what you want :).
A lot of cleanup work is probably required, and some of the files
could/should be merged back to biosboot, perhaps made conditional on
some #ifdef. The malloc implementation that comes with cdboot might
also be useful for kzipboot. (I needed a malloc() since the root dir
ain't fixed in size on a CD.)
I've been testing all this with a 2.2-STABLE as the base for biosboot.
I don't expect too many surprises, although i know the biosboot stuff
has been changed a lot in -current lately. I'm sure Bruce will
comment on all this here anyway. :-)
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
Install the biosboot as /usr/mdec/boot[12]
Make the traditional links from [swf]dboot and boot[swf]d to boot[12] files.
Install dosboot as /usr/mdec/boot/fbsdboot.exe
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.
2. Clean up the .S files to use /* */ style comments.
This is a totally cosmetic change, not one byte of the resulting boot
code changes. But at least it is installed with correct owners and in
the right places, and gets recompiled correctly when things change!
is used instead of /usr/lib
io.c: add #include <machine/cpufunc.h> as instructed by David Greenman to
avoid inb/outb linking errors.
NOTE: I just discovered that if GNUC is not used the inline functions will not be expanded from the include file and real inb/outb functions would
be needed.
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
