wombat@claris.com (Scott Lindsey) (03/30/89)
Recently, there has been a bit of talk about multitasking on an Apple, and even Unix. While it might be possible to create from scratch such an environment, literally a Unix-type OS, making one that is compatible with existing software is next to impossible. Taking the worst candidate (the IIgs): multitasking compatibly with GS/OS and the tools would be nightmarish. Neither the tools nor GS/OS are reentrant, and the tools are definitely not designed to deal with more than one application at a time. Writing even a MultiFinder, or simpler yet, a Switcher would require quite a bit of effort. Another problem is that the I/O space is open for anyone to play with. What if an application disables interrupts that the OS depends on for time-slicing. Perhaps if all applications involved are well-behaved & adhering to standards, but that is something that has been visibly lacking in GS applications. Finally, is it worth it? Yes, I know the advantages of multitasking & multi- user environments. I "grew up" computationally under Unix & I favour that system strongly, but to suggest it could be compatible with the current IIs & software is folly. -- Scott Lindsey |"Cold and misty morning. I heard a warning borne in the air Claris Corp. | About an age of power when no one had an hour to spare" ames!claris!wombat| DISCLAIMER: These are not the opinions of Claris, Apple, wombat@claris.com | StyleWare, the author, or anyone else living or dead.
lwv@n8emr.UUCP (Larry W. Virden) (03/30/89)
Scott, would it really be any different than things like Unix allowing DOS programs to run under its environment? I mean MSDOS makes assumptions about being in control of its machine as well , and yet I can, if I am masochistic enough, run numerous DOS windows on this Sun386i that I am sitting at. I dont claim that this would be easy to do on an Apple - one is going to want a fast cache, fast hard disk, etc. What I want to encourage is folks to go ahead and try porting minix, that unix clone that ran on the z80, etc. I personally am willing to give up most, if not all of my Apple II software to run in a Unix environment at home. I could sell my equipment and buy an Intel based machine to do this - or even an Atari ST - but I would rather not go thru the hassels of selling and buying if I could use what is already present in terms of hardware ... I always have the boot disks for Prodos if I want to run an Apple program bad enough. P.S. There used to BE a memory management chip for the Apple II line - any one out there ever see that in person? -- Larry W. Virden 674 Falls Place, Reynoldsburg, OH 43068 (614) 864-8817 75046,606 (CIS) ; LVirden (ALPE) ; osu-cis!n8emr!lwv (UUCP) osu-cis!n8emr!lwv@TUT.CIS.OHIO-STATE.EDU (INTERNET) The world's not inherited from our parents, but borrowed from our children.
gwyn@smoke.BRL.MIL (Doug Gwyn ) (03/31/89)
In article <9294@claris.com> wombat@claris.com (Scott Lindsey) writes: >Neither the tools nor GS/OS are reentrant, ... You're assuming that multitasking requires preemption of tasks rather than voluntary relinquishment of the CPU. That's not necessary; in fact the terminal I'm typing on right now (AT&T model 630) is multitasking, and it has neither preemptive scheduling nor memory protection.
mikes@ncsuvx.ncsu.edu (Michael Steele) (04/05/89)
In article <9294@claris.com> wombat@claris.com (Scott Lindsey) writes: >Recently, there has been a bit of talk about multitasking on an Apple, and >even Unix. While it might be possible to create from scratch such an >environment, literally a Unix-type OS, making one that is compatible with >existing software is next to impossible. > I don't advocate writing a OS from scratch. I would like to port MINIX to the GS. I've got an old MINIX Operating Systems book and I've looked at the code...although I'm not really knowledgable of some of the low level GS stuff, the code looked portable. First I would like to get a REAL unix shell running and then address the problems of multitasking. Most of MINIX is written in C and there are only a few pages of assembler to convert, most of it consists of memory moves, etc. All of the low level disk routines could be replaced by GS/OS calls. If we could get the OS to launch S16 files and EXE files much like ORCA/M I don't see the big deal in writting a shell. Now multitasking is a different matter. If MINIX will run on a 8086 based machine it should run on the GS! The Toolbox Memory Management will take care of memory problems for "good" programs. GS/OS and the 65816 have capabilities to do multitasking. Since the machine is only going to be used by one person, no big deal if crashes once or twice. The only thing I don't want to implement is virtual memory...you'll just have to have 2 meg of memory to multitask Appleworks GS with anything else. (ahhh too bad :-). The availability of MINIX, it's continued support, and free price make it and excellent package to port!!!! After all if can run on an IBM it should blaze on a GS...right?!?!? :-) Michael Steele mikes@ncsuvx.ncsu.edu If you are interested in this project or have ideas/input send me EMAIL!! -- Michael Steele mikes@ncsuvx.ncsu.edu mikes@ncsuctix.ncsuvx.ncsu.edu netoprms@ncsuvm.bitnet
RXBROWN@UALR.BITNET ("MR.FANTASTIC") (04/06/89)
Mike Steele writes..
>After all if it can run on an IBM is should blaze on a GS.....
He was talking about MINIX. Scott, Dave, Rick, or anybody else who knows
about this, I have heard about cross compliers for IBM that will convert
IBM code to work on other processors. Can this be done if the source code
is available?
Robert Brown
BITNET: RXBROWN@UALR
ALPE: ROBPHD