Subject: Re: swap_page errors
To: None <tech-kern@sun-lamp.cs.berkeley.edu>
From: Brett Lymn <blymn@mulga.awadi.com.AU>
List: tech-kern
Date: 01/07/1994 18:51:28
I am not sure whether I should be breaking out the sackcloth shirt,
ashes and birch sticks (for self-flagellation) or not.
Earlier I complained about these errors:
Jan 7 16:31:13 siren /netbsd: error 22 blkno 65976 sz 4096
Jan 7 16:31:13 siren /netbsd: sd0: illegal request
I have made the problem go away by not using the last cylinder of my
harddisk, the disklabel looks like this:
# /dev/rsd0a:
type: SCSI
disk:
label:
flags:
bytes/sector: 512
sectors/track: 71
tracks/cylinder: 15
sectors/cylinder: 1065
cylinders: 1931
rpm: 3600
interleave: 1
trackskew: 0
cylinderskew: 0
headswitch: 0 # milliseconds
track-to-track seek: 0 # milliseconds
drivedata: 0
3 partitions:
# size offset fstype [fsize bsize cpg]
a: 1990485 0 4.2BSD 1024 8192 16 # (Cyl. 0 - 1868)
b: 64965 1990485 unused 0 0 # (Cyl. 1869 - 1929)
c: 2056515 0 unused 0 0 # (Cyl. 0 - 1930)
Previously partition b was Cyl. 1869 - 1930 but I found by adding a
printf to sd.c, using ddb and a calculator that the swap code was
attempting to write to blocks outside the cylinder range given. I
suspect that if this was really the case then this bug would have been
picked up ages ago. I think I have an explanation as to what is going
wrong in my case...
The only odd this about this disklabel is that when I reboot my
machine the attach message comes up with:
Jan 7 16:07:13 siren /netbsd: sd0 at aha0 targ 0 lun 0: 990MB 1931 cyl, 15 head, 70 sec, 512 byte/sec
Note the "70 sec" which I take to mean that there are 70 sectors/track.
The label for my scsi disk was generated by the "happy install"
program of 0.1 days, it has been working for at least 9 months or so
under 0.1 386BSD.
If I take the "70 sec" as being kosher and work out the number of
cylinders occupied by the current b partition it comes out to just
under 32 cylinders (70 sec/trk = 1050 sec/cyl).
This all leaves me very confused (and embarassed), 386BSD worked fine
with the old partitioning or, more likely, did not complain.
Prior to me setting up a secondary swap partition on my scsi disk (my
primary boot disk is an ESDI drive) I used to have the entire disk for
a file system again this was under 386BSD.
I am going to go away quietly and beat myself sensless...
--
Brett Lymn, Computer Systems Administrator, AWA Defence Industries
===============================================================================
"Where a calculator on the ENIAC is equipped with 18,000 vaccuum tubes
and weighs 30 tons, computers in the future may have only 1,000 vaccuum
tubes and perhaps weigh 1 1/2 tons."
-- Popular Mechanics, March 1949
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