Path: utzoo!utgpu!watmath!clyde!att!osu-cis!killer!texbell!bigtex!pmafire!dave
From: dave@pmafire.UUCP (Dave Remien)
Newsgroups: comp.unix.microport
Subject: Re: missing 384K on V/386
Message-ID: <517@pmafire.UUCP>
Date: 1 Jan 89 00:08:16 GMT
References: <1263@altger.UUCP>
Reply-To: dave@pmafire.UUCP (Dave Remien)
Organization: WINCO, INEL, Idaho
Lines: 34

In article <1263@altger.UUCP> dirk@altger.UUCP (dirk) writes:
>I've been reading this newsgroup for a while now but I never saw the
=>following question:
=>
=>			Where did the 384K go ?
=>
=>If you install 2MB on a Compaq 386 you'll get 640K conventional memory
=>and 1024K extended memory == 1664K. When booting 386/ix it reports
=>1703936 Bytes of real memory. So, where are they ?

Two of the three '386 machines I work on (Bell Tech and Mylex) have the
3.375 megs of memory above 640K start at 0x100000 (1 meg), and continue
to 0x440000 (4.375 megs).  The other, a FORTRON, loses the 384K because
it can't remap the memory to start at 1 meg.  It's actually not
available, because that area is mapped by hardware to ROM and video RAM
:-(. 

=>
=>So, where does the memory live, I think it can not be a problem to 
=>enable it and use it with 386/ix by patching the memory scan
=>function (scanmem) in os.o. Probably it is just one more gap to cover.

Just make sure that accessing that area doesn't get you into ROM or
video.  Availability seems to depend on how they set up the (hardware)
address decoding. 

=>
=>cu,
=>dirk :-)


-- 
Dave Remien - WINCO Computer Engineering Group (only somewhat confused, now)
Work - 208-526-3523 Home - 208-524-1906 UUCP Path: ...!bigtex!pmafire!dave