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From: hand@ncsu.UUCP (Steven Hand)
Newsgroups: net.micro.amiga
Subject: Re: AmigaDOS
Message-ID: <2987@ncsu.UUCP>
Date: Mon, 3-Feb-86 18:46:38 EST
Article-I.D.: ncsu.2987
Posted: Mon Feb  3 18:46:38 1986
Date-Received: Wed, 5-Feb-86 01:38:08 EST
References: <1149@caip.RUTGERS.EDU>
Organization: N.C. State University, Raleigh
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Dawn Banks writes:

>What all of this boils down to is that (what I think is) the major failing of
>the Amiga is its resource utilization.  Sure a 40 meg hard disk and 8M of
>RAM would certainly mask the problem, however, I'm still not sure why I should
>be finding myself running out of resources so often on a machine with 512K of
>ram and two 880K byte floppies.

I agree.  A few years ago I used a PDP-11/60 with the RSX-11/M OS with 6-7
users and several background tasks, all on 128K MEMORY.  Sure it had a hard
disk and swapped tasks in and out of memory, but it shows what can be done with
a professional OS.  It's time for microcomputer OS's to catch up with what
*was* state-of-the-art years ago.

I think OS-9 would be great for the Amiga, but if you want to write your own
quality OS for the Amiga, much of the work has ALREADY BEEN DONE and can be
found in the book

            Operating System Design: The XINU Approach
            by Douglas Comer (Prentice-Hall)

(XINU stands for "XINU is not UNIX").  This very readable book contains
the *SOURCE CODE* for an entire hierarchically-structured OS with MANY features
like:
       - True multitasking.  Processes don't step on each other or crash
         the system.  The resources of *killed* processes are reclaimed.
         Processes can SHARE CODE.  Uses priorities and Round Robin scheduling.
       - Interprocess communication through two kinds of message passing.
         Ports.  NETWORKING with hooks for remote file sharing, servers,
         and diskless nodes.
       - Interrupt-driven, device-independent I/O.  Device drivers.
         Nice file system with ORDERED DISK SEEKS, pseudo-devices, indexed
         sequential access method.
       - Real-time clock, scheduled waits, semaphores (no busy waits).

The book describes how all the routines work and gives the source code in C.
It is all done in about 5800 lines of C and 650 lines of assembler, and runs
in about 4000 bytes (!).
You can get a MAGTAPE from the publisher with all this and a CROSS DEVELOPMENT
SYSTEM that runs on VAX Berkeley UNIX 4.1 or 4.2.  (Includes C compiler for
LSI-11 microcomputer, linking loader, up/down-loaders, debugger, utilities).
While the book describes an LSI-11 as the target, it mentions that students
have ported XINU to the 68000.  Maybe you can get the source for the 68000
version?

Random thoughts...
Maybe the best things about Amiga's OS (libraries, etc.) can be added to XINU.
Since the book is readily available, this could be a group project.
How about integrating the stuff from the Portable User Interface Library.
Since it is copyright 1984, maybe more has been added to the OS that
  isn't mentioned in the book (CLI, spooler, etc.)
The author is mentioned as working at Bell Labs... Are you on the net? What
  do you think?
Actually there are many other OS's out there, maybe from other university
  projects.

Lastly, this book could help the Commodore OS people make Amiga's OS better...
are you listening?

Disclaimer: I have only read the book, not actually used the OS.