Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!elroy!orion.cf.uci.edu!uci-ics!zardoz!dhw68k!arcturus!felix!kehr
From: kehr@felix.UUCP (Shirley Kehr)
Newsgroups: comp.sys.mac
Subject: Re: Virtual, how many megs?
Message-ID: <90725@felix.UUCP>
Date: 6 Apr 89 14:37:11 GMT
References: <2615@osiris.sics.se> <6514@bsu-cs.UUCP>
Sender: daemon@felix.UUCP
Reply-To: kehr@felix.UUCP (Shirley Kehr)
Organization: FileNet Corp., Costa Mesa, CA
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In article <6514@bsu-cs.UUCP> mithomas@bsu-cs.UUCP (Michael Thomas Niehaus) writes:
<In article <2615@osiris.sics.se>, ollef@osiris.sics.se (Olle Furberg) writes:
<>  How many Mb (maximum) do I get with the Virtual-init on a MacIIx/SE30 ?
<> Someone told me that I can't get more than 8 Meg. Suppose I have 8 Meg 
<> HardWare memory, is Virtual of any use?
<>  If it is a limit for Virtual, is this a general limit for the 030-MMU?
 
<This has been discussed before:  Currently, the Mac operating system
<limits you to only (and I choke on only) 8MB of memory.

I thought the question was about the Virtual init. I presumed that Olle
was either using A/UX or looking ahead to the future when the 8Mbyte
limit didn't exist.

I suspect the answer is that Virtual might not access more than 8 Mbytes
today, but that there is no reason for any limit as soon as it is usable
by the Mac. They already did a second version of the init for 030 machines
so they seem committed to keeping up. As to A/UX support, I suspect you'd
have to ask them.

Shirley Kehr


In the future,
>I would expect to see a rewrite of the OS to allow for up to 32MB, but
>right now it is not feasible.  So, in general 8MB is the limit, period,
>for any of the 020 or 030 machines.  (I believe that the reason for the
>8MB limit is that the ROM routines are mapped beginning right after this
>8MB ceiling.)
>
>Unless of course you use A/UX.  I don't believe that it has this restriction,
>allowing up to 32MB of real memory.  I remember someone recently posting a
>message saying that they were using 4MB SIMMs (a set of 4 of these) giving
>them 16 MB, all of which was usable by A/UX, but the Mac II he was using
>just ignored the upper 8MB.  Note that this didn't produce any problems.
>
>-Michael
>
>
>
>-- 
>Michael Niehaus        UUCP: <backbones>!{iuvax,pur-ee}!bsu-cs!mithomas
>Apple Student Rep      ARPA:  mithomas@bsu-cs.bsu.edu
>Ball State University  AppleLink: ST0374 (from UUCP: st0374@applelink.apple.com)