Low disk throughput on Xenix 2.3.2/1542B/wren V

[Matti Joutkoski]

jcurtis at baron..uucp (Jay Curtis) writes:


>Hi.
>	I am having a problem with SCO Xenix 2.3.2GT and very low disk
>transfer rates.  Here is my configuration:

>Adaptec 1542B DMA=5 irq=11 i/o base=330, bios enabled, 5 Meg DMA
>	transfer rate
>Wren V 330 Meg SCSI drive
>Archive 2150S tape drive

>With this config, I am only able to get 124K Bytes/sec. throughput under
>Xenix.  Under Dos I get 496 K Bytes/sec.  Under ISC Unix, similar rates
>to Dos.  Is there a known problem with the scsi drivers under Xenix?

Hi there,

This has been always the same, there is a patch which should improve the
disk performance with SCSI, but it doesn't make any difference. 

One thing you could check is, that all your SCSI-devices are in the
SYNCHRONOUS-mode. It makes difference, default parameters what I have
seen has usually been ANYNC. DMA-speed between Adaptec and Motherboard
doesn't make any difference, because the botleneck is not there.

These next words I have wanted to say all of my life:

I never seen so STUPID SCSI-drivers!!!!
---------------------------------------

>drives and controller (substitue in a wd1003 controller and Maxtor 2190)
>gave me double the disk throughput.  Why???

Yap, and if you are using some AT-IDE harddisks, you will get more disk-
performance. That's the truth. 

There have been aloooong time rumours, that SCO will release Xenix/386
version with INTERACTIVE-SCSI-drivers (at last) and the version number
is 2.3.4. It should be released during this spring.

But people who want more performance: Buy a un-expensive AT-IDE harddisk
(ex. 100 MB, almost in every modele there is cache included) and put
your root-filesystem in there. You will SEE the difference.

-- 
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Matti Joutkoski, mattij at yj.data.nokia.fi, tel. + 358-0-5673866.
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