-
Hello MLAers! We've re-enabled auto-approval for accounts. If you are still waiting on account approval, please check this thread for more information.
Unix for 8-bit Apple
- Thread starter Dog Cow
- Start date
Yeah I saw that thread. It looked like a simple way to check up on CSA2 and some of the other groups I read if Google Groups goes down, which it has done from time to time. I've also looked over your site in general and like the looks of it. When will you be posting the Apple II stuff on there that you have?
Dean
I read quite a few Usenet posts last evening on this subject, most from the late 80's. It looks like co-operative multitasking is going to be the way to go, unless one can get a card to generate interrupts every once and awhile. A program known as Daemon uses the Apple Mouse II card as its source of interrupts. Interestingly, the IIgs can be programmed, in software, to generate interrupts at varying intervals. Clearly, the superior system!
OK, maybe I'm just talking to myself by now, but I found this site in Linux Journal magazine: http://www.freertos.org/
There's no port for the 6502/Apple yet, but I'm going to take a look at it and see what I can do.
There's no port for the 6502/Apple yet, but I'm going to take a look at it and see what I can do.
I think you might be underestimating the requirements for a UNIX like OS. An 8Mhz 68000 struggles, so how a 6502 is supposed to cope I'm not sure.Might want to investigate Minix. It's designed for teaching OS design, so even if a porting effort failed, it would be an educational fail. It is to some extent unix-like.
What you have to do is stretch the definition of UNIX as much as your brain will allow in order to call the small bit of code you shoe horn into the box as something vaguely reminiscent of an idea they once had back at Bell that may have been somehow related to an operating system. If it doesn't have fork() then it ain't UNIX.
Is it more limited than a PDP-7? I've no idea what kind of comparison that would be...
Took me a bit to figure out what that meant.
Sounds to me like targetting the IIgs, because it has the most resources, including a built-in source of interrupts, would make sense.
Bah, that's like MachTen or Mac06 on the Mac. Doesn't count!
Targetting the GS first would be helpful as a springboard, learning some techniques for crunching down to low specs. Sure the architecture is quite a bit different, but some of the principles should be the same.
The WDC 65816 (also: 65C816), a 16-bit microprocessor CPU developed by the Western Design Center (WDC), is an expanded and compatible successor to the venerable MOS Technology 6502. The number 65 in the 65816's name comes from the 6502 compatibility, and 816 signifies that it can work in both 8 and 16 bit modes.
If you're like me and don't really have a clue about interrupts, Interrupts in 65xx processors is a starting point.
The PDP-7 was an 18-bit machine. Has a "real Unix" ever been developed for any 8- or 16-bit machine? Doesn't seem a big stretch to run in 16 bits.
The original QNX ran on 8088. It used the 8086 segmented model so a single process could use a maximum of 64k code+data+stack combined. And fork() really worked because it simply copied the whole proces image and used different segment register values. All pointers were, and had to be 16 bit ( AKA small model ). Processes could also be moved in memory. There was no memory protection at all and if you used assembler you could easily trash the system.
My comment was based on what I read about it on Wikipedia, etc. I've never even seen a PDP-7.
Similar threads
