home *** CD-ROM | disk | FTP | other *** search
- Newsgroups: comp.sys.mac.system
- Path: sparky!uunet!mnemosyne.cs.du.edu!nyx!jelmore
- From: jelmore@nyx.cs.du.edu (Jay Elmore)
- Subject: Re: sys 7.01 memory problems
- Message-ID: <1992Nov12.184016.3732@mnemosyne.cs.du.edu>
- X-Disclaimer: Nyx is a public access Unix system run by the University
- of Denver for the Denver community. The University has neither
- control over nor responsibility for the opinions of users.
- Sender: usenet@mnemosyne.cs.du.edu (netnews admin account)
- Organization: Nyx, Public Access Unix at U. of Denver Math/CS dept.
- References: <1992Nov12.140219.20519@aio.jsc.nasa.gov>
- Date: Thu, 12 Nov 92 18:40:16 GMT
- Lines: 25
-
- In article <1992Nov12.140219.20519@aio.jsc.nasa.gov> frisinge@aio.jsc.nasa.gov (Greg Frisinger) writes:
- >Help me please.
- >
- > I have a MacIIci with 20 meg of memory. When I select the 32 bit mode in
- >memory under the control panel, the system takes up 982k of memory. When I
- >have the 32 bit mode off the system then takes 12,961k of memory. Could
- >anyone explain why this happens.
- >
- >Thanks.......
- >
- >
- >
- All Macs require 32-bit addressing to recognize quantities of memory
- higher than 8 MB. (Not all Macs support 32-bit addressing, though...) If you
- have more than that and 32-bit addressing is turned off, System 7.x
- compensates for this by allocating the extra memory
- to the system heap (where is unreachable by applications) but doesn't
- use it. If it didn't you could receive addressing errors if it tried to use
- the extra memory (for an awful analogy, try putting mail into mailbox 1,253
- when someone leaves the 1 off...but when you got to box 253, it's full of
- mail...what do you do? if you're a Mac, you bomb.)
-
- Hope this helps!
-
- Jay (=
-