Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!uunet!pcrat!rick
From: rick@pcrat.uucp (Rick Richardson)
Newsgroups: comp.unix.i386
Subject: Re: 6386 WGS Questions
Keywords: Compatability Questions
Message-ID: <1989Nov11.132424.2550@pcrat.uucp>
Date: 11 Nov 89 13:24:24 GMT
References: <6358@cbnewsm.ATT.COM> <4615@cbnewsc.ATT.COM> <16@zds-ux.UUCP>
Reply-To: rick@pcrat.UUCP (Rick Richardson)
Organization: PC Research, Inc., Tinton Falls, NJ
Lines: 153

In article <16@zds-ux.UUCP> gerry@zds-ux.UUCP (Gerry Gleason) writes:
>Wait a minute, if you can read the physical format, you should be able to
>mount it.  Isn't a System V file system a System V file system (with the
>possible exception of version skews).
>
>What gives?

Byte order isn't specified and structure padding in "struct filsys"
(the superblock) will nail you.  The following *GROSS HACK* I wrote
to convert SVR2 floppy filesystems under Venix System V/286 to and
from UNIX/386 Release 3.2 filesystems under 386/ix.  I didn't have
to contend with byte order, but I did have to deal with structure
padding.

Also note that the on disk free list of Venix is different, too.
In my kludge I ignored it, since fsck will rebuild the freelist.

People interested in converting filesystems can use this program
to give them an idea of what the problem is.  I urge you, however,
to throw this one away and perhaps think of a cleaner method.  My
only excuse was that I was in a hurry -- I archive all comp.sources
from the 286 unto mountable floppies, the 286 was down, and I needed
to get some source code from the floppies onto the 386.

-Rick

#! /bin/sh
# This is a shell archive, meaning:
# 1. Remove everything above the #! /bin/sh line.
# 2. Save the resulting text in a file.
# 3. Execute the file with /bin/sh (not csh) to create:
#	fs2s5.c
# This archive created: Sat Nov 11 08:14:54 1989
export PATH; PATH=/bin:/usr/bin:$PATH
if test -f 'fs2s5.c'
then
	echo shar: "will not over-write existing file 'fs2s5.c'"
else
sed 's/^X//' << \SHAR_EOF > 'fs2s5.c'
X#include <stdio.h>
X
Xchar	buf[512];
Xchar	buf2[512];
Xlong	zero = 0;
Xlong	clean = 0x7c269d38L;
Xint	fd;
X
Xmain()
X{
X
X	fd = open("/dev/fh0", 2);
X	lseek(fd, 512L, 0);
X	read(fd, buf, 512);
X	if (buf[2] == 0 && buf[3] == 0)
X	{
X		printf("Converting to Venix Filesystem\n");
X		memcpy(&buf2[0], &buf[0], 2);
X
X		memcpy(&buf2[2], &buf[4], 4);
X
X		memcpy(&buf2[6], &buf[8], 2);
X
X		memcpy(&buf2[8], &buf[12], 200);
X
X		memcpy(&buf2[208], &buf[212], 2);
X
X		memcpy(&buf2[210], &buf[214], 200);
X
X		memcpy(&buf2[410], &buf[414], 1);
X
X		memcpy(&buf2[411], &buf[415], 1);
X
X		memcpy(&buf2[412], &buf[416], 1);
X
X		memcpy(&buf2[413], &buf[417], 1);
X
X		memcpy(&buf2[414], &buf[420], 4);
X
X		memcpy(&buf2[418], &buf[424], 8);
X
X		memcpy(&buf2[426], &buf[432], 4);
X
X		memcpy(&buf2[430], &buf[436], 2);
X
X		memcpy(&buf2[432], &buf[438], 6);
X
X		memcpy(&buf2[438], &buf[444], 6);
X
X		memcpy(&buf2[504], &buf[504], 4);
X		memcpy(&buf2[508], &buf[508], 4);
X	}
X	else
X	{
X		printf("Converting to 386/ix Filesystem\n");
X		memcpy(&buf2[0], &buf[0], 2);
X		memcpy(&buf2[2], &zero, 2);
X
X		memcpy(&buf2[4], &buf[2], 4);
X
X		memcpy(&buf2[8], &buf[6], 2);
X		memcpy(&buf2[10], &zero, 2);
X
X		memcpy(&buf2[12], &buf[8], 200);
X
X		memcpy(&buf2[212], &buf[208], 2);
X
X		memcpy(&buf2[214], &buf[210], 200);
X
X		memcpy(&buf2[414], &buf[410], 1);
X
X		memcpy(&buf2[415], &buf[411], 1);
X
X		memcpy(&buf2[416], &buf[412], 1);
X
X		memcpy(&buf2[417], &buf[413], 1);
X		memcpy(&buf2[418], &zero, 2);
X
X		memcpy(&buf2[420], &buf[414], 4);
X
X		memcpy(&buf2[424], &buf[418], 8);
X
X		memcpy(&buf2[432], &buf[426], 4);
X
X		memcpy(&buf2[436], &buf[430], 2);
X
X		memcpy(&buf2[438], &buf[432], 6);
X
X		memcpy(&buf2[444], &buf[438], 6);
X
X		memcpy(&buf2[500], &clean, 4);
X		memcpy(&buf2[504], &buf[504], 4);
X		memcpy(&buf2[508], &buf[508], 4);
X	}
X	lseek(fd, 512L, 0);
X	write(fd, buf2, 512);
X
X	close(fd);
X
X	exit(0);
X}
X
Xfreelist(slen)
X{
X}
SHAR_EOF
fi
exit 0
#	End of shell archive
-- 
Rick Richardson |       Looking for FAX software for UNIX/386 ??????     mention
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