From: Drew Eckhardt (drew@kinglear.cs.colorado.edu)
Date: 08/09/93


From: drew@kinglear.cs.colorado.edu (Drew Eckhardt)
Subject: Re: Adaptec 1542B & > 16mb
Date: Mon, 9 Aug 1993 05:17:19 GMT

In article <1.9768.2381.0N278FFB@satalink.com> john.will@satalink.com (John Will) writes:
>I've read the FAQ, but I can't seem to find anything about Adaptec 1542B
>HA's and memory sizes greater than 16mb on the ISA bus. Is this a problem
>with the pl12 kernel, or has this been addressed?

The Linux SCSI code will double-buffer for addresses > 16M if the
low level driver requests it, as is the case for the 1542 and
other ISA dma using low-level drivers.

>If this is possible, how much of a performance hit do you take with the
>double-buffering for processes in the 16-32mb range?

Not a noticeable one.

-- 
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Condemn Colorado for Amendment Two.                    | Drew Eckhardt
Use Linux, the fast, flexible, and free 386 unix       | drew@cs.Colorado.EDU 
Will administer Unix for food                          |