From mboxrd@z Thu Jan  1 00:00:00 1970
Message-Id: <200205260302.g4Q31xS1037269@ducky.net>
To: 9fans@cse.psu.edu
From: Mike Haertel <mike@ducky.net>
Subject: [9fans] bug in disk/format
Date: Sat, 25 May 2002 20:01:59 -0700
Topicbox-Message-UUID: 9c6f9b62-eaca-11e9-9e20-41e7f4b1d025

Here is a report of a bug in disk/format that results
in broken 9fat partitions that won't boot.

The test system is using a 9GB IBM SCSI disk drive
connected to an 53c875 based controller.  Plan 9
is the only operating system on this computer.

term% cat /dev/sd01/ctl
inquiry IBM     DGHS09Y         03E0682B91A1GAGSPMT03E
geometry 17916240 512
part data 0 17916240
part plan9 63 17912475
part 9fat 63 20545
part fs 20545 16971267
part swap 16971267 17912475

In this demonstration, /dev/sd01/9fat initially contains all
bytes 0 except for the Plan 9 partition table in block 1.

Now we run disk/format following the example in the
man page:

term% disk/format -b /386/pbs -d -r 2 /dev/sd01/9fat /386/9load /386/9pcdisk /tmp/plan9.ini
Initialising FAT file system
type hard, 10 tracks, 64 heads, 32 sectors/track, 512 bytes/sec
Adding file /386/9load, length 177320
Adding file /386/9pcdisk, length 1744105
Adding file /tmp/plan9.ini, length 185
used 1927168 bytes

Now, using dossrv, we unfortunately find that 9load and
9pcdisk were not copied correctly!

term% 9fat:
term% cmp /386/9load /n/9fat/9load
/386/9load /n/9fat/9load differ: char 55809
term% cmp /386/9pcdisk /n/9fat/9pcdisk
/386/9pcdisk /n/9fat/9pcdisk differ: char 1

The system crashes in 9load when I try to boot from
the resulting 9fat partition.

Using dossrv and cp I was able to manually recopy 9load
and 9pcdisk to the 9fat partition to make a bootable system,
but this would be a bad experience for a new user.