Xref: utzoo comp.sys.m6809:863 comp.os.os9:89
Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!elroy!mahendo!wlbr!pete
From: pete@wlbr.EATON.COM (Pete Lyall)
Newsgroups: comp.sys.m6809,comp.os.os9
Subject: Re: os9 level 2 woes!
Message-ID: <22823@wlbr.EATON.COM>
Date: 18 Aug 88 23:09:03 GMT
References: <8808172042.AA01032@decwrl.dec.com>
Reply-To: pete@wlbr.UUCP (0000-Pete Lyall)
Organization: Eaton IMS, Westlake Village, CA
Lines: 51

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.I noticed that when the shell is
>     linked at startup,19 extra command modules are also loaded into
>     RAM.I wanted to get rid of some of these because I don't use them
>     enough to justify the space.At this point, mfree showed 48K.
>     I used the level 1 save command to save just the shell module,
>     and put it in my cmds directory.Now everything boots alright and
>     the shell works alright,but I ended up losing memory instead
>     of gaining it.I only have 40K now.It seems like OS9 is still
>     assigning the memory that old shell command(shell+19 modules)
>     required.aaaarrrrrgggghhhhh!


This is because of the way level II, and specifically the Tandy
implementation of it, work.

Memory is allocated in 'blocks' under LII, not in pages as in Level I.
On most sane 6809/os9 systems, block size was 4K (or 2K) and the
physical memory limitations (addressing lines + DAT) allowed for a meg
of RAM. Under the Tandy scheme, you have a 512K ceiling (a limitation
in the GIME chip), and your block size is 8K. That means no matter how
little you load into it, you lose 8K at a whack (system memory
excepted). The best idea here is to use each 8K block to its fullest
potential - that is, FILL IT UP. That means merging several smaller
modules together so that when one loads, they all load. The best bet
here it to group frequently used utilities, or at least utilities that
are related, together. This is what they did with 'Shell'. If you do
an IDENT on the /dd/cmds/shell file, you'll see that they stuffed a
lot of the frequently used file management tools into the file as well
(DEL, LIST, etc.).  Actually, because there's a 512 byte area that's
reserved across the top of all address spaces, it's best to keep the
merged modules at or below $1E00 in length. If you don't, you'll find
that the merged modules cannot be loaded in the top block of a 64k
adress space, and you'll effectively lose 8k.

In summary - leave things as they are! You're not 'paying any extra'
to have those additional tools in RAM - they'll actually cost you more
to use if you split them up. Also, it's pretty widely know that
os9/LII for the coco3 without 512k is awkward at best. Limp along if
you have to, but set your sights on a 512k board. Hope this helps.

Pete


area at the top of each address space, you should only try to use
$1E00 of it (instead of $2000).
-- 
Pete Lyall (OS9 Users Group VP)|  DELPHI: OS9UGVP  |  Eaton Corp.(818)-706-5693
Compuserve: 76703,4230 (OS9 Sysop) OS9 (home): (805)-985-0632 (24hr./1200 baud)
Internet: pete@wlbr.eaton.com            UUCP: {scgvax,jplgodo,voder}!wlbr!pete