Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!uunet!munnari.oz.au!uhccux!bigtuna!pegasus!richard
From: richard@pegasus.com (Richard Foulk)
Newsgroups: comp.unix.sysv386
Subject: Re: Is >16MB possible on ISA box (ISC 2.2.1)?
Message-ID: <1991May13.004012.18572@pegasus.com>
Date: 13 May 91 00:40:12 GMT
References: <1991May9.183908.9194@aai.com> <1991May11.131528.17370@virtech.uucp>
Organization: Pegasus,  Honolulu
Lines: 19

>>The EISA support update says it's ONLY for EISA bus computers.  The kconfig
>>options only mention 4M, 8M, and 16M.  Will ISC use any memory over 16M on
>>an ISA machine, or is it ignored?  Is there some other update that
>>addresses this?  Will the EISA update work on an ISA machine?
>
>No.  The problem is that DMA will not work from a device on the ISA bus
>to memory above 16MB.

Okay, so ISC blew it.  It IS possible to run ISA bus Unix with greater
than 16 megs of memory.  DMA is not a necessity.  I've seen people
reporting 24 megs and more, in this forum, on ISA bus machines.

So what is the real situation today?  Which 386 ports of Unix will support
greater than 16 megs on the ISA bus?  (Did the MEMRANGE spec actually
vaporize with ISC's 2.2, or is it just hiding somewhere else?)


-- 
Richard Foulk		richard@pegasus.com