Xenix device drivers under Unix

[Ronald Khoo]

In article <4552 at cps3xx.UUCP> jhl at frith.egr.msu.edu () writes:
>While I have your ear, does anyone know if SCO UNIX has gotten rid of
>the silly limit of only seeing 1024 cylinders on a disk that SCO XENIX
>had?

Eh?  Xenix didn't have this problem at all, only the documentation
did!  Yes, I *know* that the release notes say only 1024 are supported,
but there doesn't seem to be any problem going above that.  At least,
not if the *controller card* can handle it, but then all WD cards
starting from WD1003 and more modern can.  For standard ST-506
controllers, I can heartily recommend the WD1006.  With 1:1 interleave,
it screams along quite merrily. 

(hey, rosso at sco, why did the release notes say 1024 only ?)

Under SCO Xenix 2.3.1 and later, you can even have 2 controllers,
and this makes things go *really fast*  I am using 2 WD1007A ESDI
controllers, with one disc on each, and am getting terrific I/O
performance from the machine.  And yes, one of the discs has 1224 cylinders
which I had no problem with even when I was using Xenix 2.2.3 last week.

But there's no doubt that adding the second controller is definitely
a worthwhile investment--for an application mix which is mostly
disc bound, meaning anything not development or CAD oriented, really,
it actually effectively doubles the number of users you can support!

-- 
Ronald.Khoo at ibmpcug.CO.UK (The IBM PC User Group, PO Box 360, Harrow HA1 4LQ)
Path: ...!ukc!slxsys!ibmpcug!ronald Phone: +44-1-863 1191 Fax: +44-1-863 6095
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