🚀 go-pugleaf

All these arguments sound wonderful until you remember that the Mac had a 
GUI with oodles of overhead. A single text-edit window would require say, 
15K for the document, and another 2-3K for the graphical stuff. A single 
bit-mapped font might require 5-10K, and the screen buffer (part of RAM) 
would require (512x384)/8 = ~24K. As I recall, after the OS, GUI, etc, 
was loaded, there was a whole 40K left for the application and all of its 
data structures, including the GUI-related ones.

Apple implemented a software-based virtual memory system for application 
code using CODE resources, the Segment Manager and the Resource Manager. 
It was all quite elegant, considering the hardware constraints...

The Lisa HAD an ASIC MMU as I recall, and cost 4x as much.

Robert Salasidis (salasidis@medcor.mcgill.ca) wrote:
: orc@pell.com (Orc) wrote:
: > In article <DC8s5E.Bv1@ecf.toronto.edu>,
: > PISCHKE  DAVID <pischke@ecf.toronto.edu> wrote:
: > >In article <3v0ue9$9ls@sashimi.wwa.com>, G <blackbob@sashimi.wwa.com> wrote:
: > >>This, of course, is false.  The Amiga multitasked just fine using
: > >>just floppies.  The original implementation of UNIX also had one
: > >>megabyte of disk (compare to Macintosh with two floppies).  Minix
: > >>is a complete UN*X clone which runs on XT's with two 360k floppies
: > >>(one can even recompiled the kernel in this system).  Etc.
: > >Early Macintoshes had 128K of RAM and one 400K floppy drive.  The Amiga, when
: > >it first came out, have 256K of RAM and one 880K floppy.
: > >Are you telling me you can fit a pre-emptive multitasking operating system
: > >into 128K of RAM and 400K of disk space, and still have room left for 
: > >an application, its support files and documents?  I find that hard to
: > >believe!
: >    Why?   If you've got the hardware, all it takes is some sensible
: > kernel coding to protect critical areas, the code to swap processes
: > in and out, and, hopefully, some code to handle semaphores so multiple 
: > people can chatter at the same thing at the same time.  Of course you
: > have to have the hardware, and in 1984 the price of a good mmu would
: > have made the Mac a whole lot more expensive.



: When QNX first came out (http://quics.qnx.com) in 83, it ran from
: a single 360k floppy on a 256k system. It had preemptive multitasking,
: a good C complier for the time, and applications could be developed
: using the floppy for temporary storage (admittedly when I got a hard drive
: and extra RAM a few months later it did make it a lot better to use.













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