Xref: utzoo comp.sys.m6809:867 comp.os.os9:91
Path: utzoo!utgpu!attcan!uunet!mcrware!jejones
From: jejones@mcrware.UUCP (James Jones)
Newsgroups: comp.sys.m6809,comp.os.os9
Subject: Re: os9 level 2 woes!
Summary: CoCo3 GIME chip hands out memory in BIG (8K) hunks
Message-ID: <726@mcrware.UUCP>
Date: 18 Aug 88 12:16:33 GMT
References: <8808172042.AA01032@decwrl.dec.com>
Organization: Microware Systems Corp., Des Moines, Ia.
Lines: 26

In article <8808172042.AA01032@decwrl.dec.com>, burke_vern@mtblue.dec.com (WHY BE NORMAL?) writes:
> 	I recently outfitted myself with a 128K CoCo III,2 floppy drives,
>      and OS9 level 2(version 02.00.01).I've been having some difficulty
>      getting some extra memory space.

...followed by some, as SubGeniuses would say, puzzling evidence.  It's not as
puzzling, though, once you know about the GIME chip.

The GIME chip does lots of stuff, and one of the things it does is memory
mapping.  I don't know the design tradeoffs involved, not having had anything
to do with it, but it turns out that the GIME maps memory in units of 8 (count
'em 8) K.  This is VERY large compared to other OS-9 Level Two systems, and it
can eat memory up quickly if you're not careful.

All those other modules that you pulled out of the stock "shell" file were
there because it didn't hurt anything--the shell is only about 1.5K, so that
leaves 6+K out of an 8K hunk that would otherwise be wasted.  OS-9 can't map
memory in units smaller than the hardware supports, so you didn't gain anything
by putting only the shell in /dd/cmds/shell, and when you ran mfree, it had to
be loaded instead of already being there when you loaded /dd/cmds/shell, so
poof!  another 8K gets allocated and you see 40K free instead of 48K free.

I personally don't understand why the stock CoCo 3 is sold with 128K, because
windows can eat memory pretty quickly.  You should get more memory.

		James Jones