mwm@VIOLET.BERKELEY.EDU.UUCP (02/24/87)
>> I find it hard to believe that you are not just joking! You obviously like >> the flavor of your foot, but I guess we all are entitled to an opinion. Yup. And some of us go out of our way to look at the facts behind other peoples opions before flaming about them. >> I, too, had a small system, but I learned that a UNIX type system, with >> memory managment, Vmem, process forking, etc., unleashes power one couldn't >> dream of before. I suggest you send your messages about things you obviously >> have no knowledge about to /dev/null. That is, type 'cat > /dev/null'... Gee, the biggest, fastest Unix box I can get to (both legitimately and otherwise) doesn't have VM. Their attitude is "Real memory for real performance." Maybe the hardware designers know something you don't? If not, "how come you ain't rich?" :-) There's a place for everything. Given a 68K based system, I'd rather not have virtual memory - just give me 16Meg of real, and forget the virtual. An MMU would still be nice, though. But if I can save 10% of the cost of producing a box, and I'm planning on selling it in a market that doesn't need an MMU, then I'd be stupid to put one in. For instance, that's why the Amiga doesn't have an MMU; the looked at it, and were looing at $125 for the CPU board. Even at $10 for the parts (and who knows what for the board space), that's not a good trade. If you think you have to have an MMU, then either wait for the cost of MMU'ed systems to drop, or spend several times as much money as you would for a system without one. As for Unix proper - it's got serious problems. The worst is that the system calls have long since gotten past the point of having been designed, and have "grown" to be what they are. Starting over from scratch, and building a system that emulates Unix on top of a reasonable OS (which is what Minix is) is a _good_ thing. Period. The trick is to then get all those Unix utilities (hopefully, after rewriting them to regularize the argument parsing & delete cruft that's been added to solve problems you solved in a better way) running on your system. That's harder, 'cause you have to talk AT&T out of the sources, or rewrite all of them. <mike
bandy@amdcad.UUCP.UUCP (02/24/87)
>>> I, too, had a small system, but I learned that a UNIX type system, with >>> [...] Vmem [...] unleashes power one couldn't dream of before. > >Gee, the biggest, fastest Unix box I can get to (both legitimately and >otherwise) doesn't have VM. Their attitude is "Real memory for real >performance." Maybe the hardware designers know something you don't? Right, while it doesn't have vm, it does have memory management - upper and lower bounds registers, if I remember properly. It has just enough memory management to keep people separated from each other. >There's a place for everything. Given a 68K based system, I'd rather >not have virtual memory - just give me 16Meg of real, and forget the >virtual. Right. If you don't have applications that run in more memory *than you can afford*, then you don't need vm (aside from the fact that with it you can cut down your swapping). Now, I can't afford to put together more than 256k worth of ram (I have to start haunting the surplus shops and try to find some *cheap* ram) in my system and I'd really rather not try to swap to a slow device (or use the "parent and child run in the same address space" approach -- *slow*!), so it seems that for me, putting an mmu of any sort into my system (even a 68451) is a win -- it makes unix run much cleaner and it allows me to make the best of the small system that I have. andy -- Andrew Scott Beals, {lll-crg,decwrl,allegra}!amdcad!bandy +1 408 749 3683