9 Dec
2001
9 Dec
'01
12:53 p.m.
Since the OS provided file and byte I/O system functions for applications to
call, only the console command interpreter was reloaded on exit, and that only
when the application was large. I guess this was an issue for CP/M systems that
didn't have the full 64K of RAM, but I never worked with one that didn't for
more than half a day. Vector and Northstar systems, and probably a few others
that maintained a ROM BASIC may have had less RAM, but my own experience started
and ended with 64K RAM under CP/M.
On the Apple, the DOS had to be smaller, since there was only 48K of RAM unless
the extra 16K was present. on an add-on card. Of course, when the 16K board was
present, it was often so that CP/M could be used via the Z80 board.
Dick
----- Original Message -----
From: "Eric J. Korpela" <korpela(a)ssl.berkeley.edu>
To: <classiccmp(a)classiccmp.org>
Sent: Sunday, December 09, 2001 11:26 AM
Subject: Re: Apple Floppy Drives (was: More Apple Pimpers)
^^^^ I must have been tired. This should have
said program.
Eric
> > They probably existed, but I don't
recall ever seeing a non-bootable
program disk for an Apple II. And data
disks are not much use without program disks.
You needed to use a special disk in order to not include DOS on an Apple
disk. It did free up a small bit of space. Apple's minimalist DOS was so
small it was rarely worth the effort. Program loads didn't obliterate the
resident portion of DOS.
CP/M on the other hand took significant disk and RAM space for the DOS and
command interpreter, portions of which were lost on program load and needed
to be reloaded on return to the OS.
Eric