parameters on CDC Wren IV, Adaptec 1542b

[Larry Snyder]

bill at unixland.uucp (Bill Heiser) writes:

>I ran the SCSICNTL.EXE program to examine my CDC Wren IV (hooked up
>to an Adaptec 1542b), and have some questions about the appropriate 
>settings.  The system is running Esix Rev D (SYSVR3 Unix).

>Parameters:

>                       Defaults      Current     Options

>Disable Correction     enabled       enabled
>Transfer on error      enabled       enabled
>post error             disabled      disabled
>early error correction disabled      disabled
>read continuous        disabled      disabled
>transfer block         disabled      disabled
>auto read allocation   disabled      disabled
>auto write allocation  disabled      disabled
>retry count               27           27        1-255
>buffer full ratio          4            4        0-255
>buffer empty ratio         4            4        0-255
>[a bunch of stuff about tracks/sectors per zone skipped for now]
>write index enable     disabled      disabled
>cache enable           disabled      disabled


>What are the best settings to have on these parameters in my application?

what you need to do is to change one item at a time - then
bench the system, change another - then bench, etc..   

I have cache enabled (made a 10% difference) and changed the
buffer ratios from 4 to 16 (made a + difference on large disk IO,
and - on small; but since most of mine is large - I changed it)..




>Thanks in advance...

>Bill

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