> 16MB on ISA bus, with aha1542a
steve at cdp.UUCP
steve at cdp.UUCP
Wed Jul 11 10:50:00 AEST 1990
Hi.
I am trying to run over 16MB on an ISA bus machine
(that holds 24MB). We use an adaptek aha1542a SCSI
controller, and realize that it cannot DMA into
memory over 16MB.
I heard in this group of some parameters in the AT&T
UNIX kernel "3.2...", that allocate kernel buffers
to be used for DMA, when there is a request to DMA
into memory in certain ranges. Presumably, any
3.2.* UNIX that has these parameters, is capable of
disallowing DMA to memory over 16MB. The parameters
are called DMAEXCL and DMAABLEBUF.
I am running Interactive 2.0.2, and it doesn't have
DMAABLEBUF. I wonder if the new release (2.0.2)
does. Can anyone running 2.2 tell me. You could
just do :
egrep DMA /etc/conf/cf.d/*tune
and post/mail the results.
I have heard that this functionality was added in
AT&T release 3.2.2, so if Interactive's porting base
was 3.2.2, those parameters should be there.
Steve Fram
Community Data Processing (CdP)
{pyramid, hplabs, ...}!cdp!steve
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