Re: memory & filesystem corruption under heavy load?

Robert L Krawitz (
Sun, 7 Apr 1996 10:47:46 -0400

Date: Sun, 7 Apr 1996 01:10:08 +0000 (GMT)
From: Gerard Roudier <>

I am the first user of ncrBsd2Linux and I do'nt have any problem
with it. I use it on 2 machines, my personnal computer at home and
on the work station at work. These machines run linux-1.2.13 (more
stable than 1.3.8X). I run recent versions of linux on my
personnal machine only for testing.

I run 1.3.8X. Running 1.2.13 would give me lots of problems, since I
rely on some of the 1.3 stuff (most notably the new version of PPP).

The most probable software problem that you can have with SCSI subsystem

I don't get any timeout messages, though.

The current value that are defined in the middle and just-above-middle scsi
drivers are, at my opinion, too short.

For example:
- SD timeout is 7 seconds.
- A HD can spend more 2 seconds sometimes for head recalibration.
- Tagged Queueing Devices may reorder requests.
- You may have more that 4 drives on a controller (max 15).
- You may use other fast devices that load CPU, memory, bus, ...
- You may have lots of interrupts.
- Some bad scsi devices may not fairly disconnect the scsi bus.
- Etc...

Now, do you agree that 15 seconds seems to be a more reasonnable value
for SD timeout ?


To set ncrBsd2Linux in the same configuration as Drew's driver, you shall
disable Disconnection Privilege. Unfortunately, this option is not easy to
set. You have to patch manually the driver code.
Wide, Sync and CmdQueue capabilities can be disabled by editing ncr53c8xx.h
and changing some values in the table of device capabilities.

At my opinion, it is quite bad to use a SCSI bus without disconnections.

I completely agree.

Must I guess that you use Drew's driver ?
Do you use it with ALWAYS_DISCONNECT, ALWAYS_SYNCHRONOUS, and some other
10 MB/sec configuration options ?

MB/sec along with OPTION_DISCONNECT.

Robert Krawitz <> 

Member of the League for Programming Freedom -- mail Tall Clubs International -- or 1-800-521-2512