[TUHS] 4.4BSD installed image or login shell?
Jeremy C. Reed
reed at reedmedia.net
Sat Apr 21 02:56:32 AEST 2012
On Fri, 20 Apr 2012, Nick Downing wrote:
> OK, I hadn't been aware of the significance of the 2 in 4.4BSD-Lite2, so
> I understand it contains a CSRG version of the startup code, etc that
> was originally from AT&T and was left out of 4.4BSD-Lite? Is it
> anything to do with Jolitz's work on 386BSD? Does it have anything
> else? Searching threw up a few results on multiprocessor locking so
> maybe it contains additional features as well as just the missing code?
> cheers, Nick
It doesn't appear to include the needed code. From looking at huge diff,
I don't see any additions identified from Jolitz/Telemuse/386BSD. (For
example, Lite already had Jolitz i386 code and Lite2 only had minimal
changes to the code.) I quote from Cover.rel2 document for Lite2:
``It will not be possible to compile or run this software without a
pre-existing system that is already installed and running. In addition,
the distribution does not include sources for a complete system. It
includes source code and manual pages for the C library, approximately
90% of the utilities distributed as part of 4.4BSD, and most of the
kernel (the same subsystems that were deleted in Net/2 are still missing
in 4.4BSD-Lite Release 2 (support for executing files, doing physical
I/O, managing the buffer cache, handling process tracing, terminal
character I/O, and doing accounting).''
The diff is huge. Lite2 has many changes: ``includes the copy editing
work done for the Usenix/O'Reilly manuals as well as numerous bug fixes
and enhancements that have been accumulated in the year since the
release of 4.4BSD-Lite. Of particular interest are the changes needed to
port the system to 64-bit architectures, important security enhancements
to TCP/IP, and much improved functionality for the union and
log-structured filesystems.'' (See
http://mail-index.netbsd.org/current-users/1995/03/23/0008.html or the
Cover.rel2 document.) I think is also incorporates many changes
already done by BSDI, NetBSD, and FreeBSD.
By the way, the TUHS page at
http://minnie.tuhs.org/cgi-bin/utree.pl?file=4.4BSD lists some files
removed to create Lite. Actually per filenames, only the sysv_shm.c and
shm.h and cpio.c files were removed. (cpio replaced with pax.) All were
modified. (That TUHS page also has two mistakes: lists /sys/sys/buf.h
twice and misspells /sys/ufs/inode.h as indode.h.)
The Restricted Files also listed: sys/kern/kern_physio.c,
sys/kern/vfs_bio.c, and sys/sys/tty.h and they are still included in
Lite. Probably because files were not included in historical AT&T code,
because newer USL code did include them, lots rewritten and so if any
code was reused it became insignificant and was agreed on. vfs_bio.c
was mentioned in a declaration stating is was based on published
pseudo-code.
Where is the actual list of files missing in Lite (that are in
Encumbered)?
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