ripley@tubopal.UUCP (Hans-Ch. Eckert) (08/01/90)
[Another message I wanted to mail but it bounced... :-( ] [Q: How to use diskspace as additional memory?] How do you want to handle page faults (or similar)? The 68000 has a bug there and cannot continue exactly at the point the missing data got it! With a 68010 it'd work, but then you have the different stack-allocation at traps... That's why TOS has to be patched to work with a 68020 (PAK-68) and some programs won't work anymore - even some which don't do illegal things... It should work on a TT. Greetings, RIPLEY -- Greetings from RIPLEY | UUCP: ripley@tubopal.UUCP (ripley@opal.cs.tu-berlin.de) Hans-Christian Eckert | ...!unido!tub!opal!ripley (Europe) D-1000 Berlin 30 | ...!pyramid!tub!opal!ripley (World) Regensburger Str. 2 | BITNET: ripley%tubopal@DB0TUI11.BITNET (saves $$$)
stripes@eng.umd.edu (Joshua Osborne) (08/03/90)
In article <1700@troll.tubopal.UUCP> ripley@tubopal.UUCP (Hans-Ch. Eckert) writes: >[Another message I wanted to mail but it bounced... :-( ] > >[Q: How to use diskspace as additional memory?] >How do you want to handle page faults (or similar)? The 68000 has a bug >there and cannot continue exactly at the point the missing data got it! I wouldn't call it a bug. I doubt the 68000 ever had "support VM" in it's design spec, and MC never tryed to fool anyone into thinking it did support VM. ('tho a great many little Unix boxes used the 68000 with swaping, not paging, and they used the XOR insn to hit the lowest point on the stack that a function would use, as part of some kludge that the ST can't do anyway because it's "MMU" really doesn't do any V->P mapping). At worst it's a design oversite in the 68000. The 68010 was really the first in the 68K line that was designed to support VM. -- stripes@eng.umd.edu "Security for Unix is like Josh_Osborne@Real_World,The Mutitasking for MS-DOS" "The dyslexic porgramer" - Kevin Lockwood "Don't try to change C into some nice, safe, portable programming language with all sharp edges removed, pick another language." - John Limpert
7103_2622@uwovax.uwo.ca (Eric Smith) (09/11/90)
In article <1407@wet.UUCP> nut@wet.UUCP (adam tilghman) writes: >In article <1990Jul31.165603.20869@msuinfo.cl.msu.edu> schultzd@kira.uucp (David Schultz) writes: >> >>2.) Is there any program that allows you to use a floppy drive as >>swap space to get more memory in an ST. I realize this would be >>painfully slow, but until I can afford more mem, it would have to do. >>It would be infinitely more helpful on a nig hard drive. (Set aside >>an x meg partition on the hard drive and treat it as internal memory. >>Virtual mem on the ST!!!) > > If you are using just a plain-vanilla 68000 in your machine, this is >completely impossible. Anything's possible :-). It's true that the 68000 doesn't support demand paged virtual memory. (If you really must have it, you can always write an interpreter for a virtual machine; but this will be *slow*). However, swapping whole processes in and out of memory is possible, if the processes don't intercept any interrupt vectors and don't mess with memory they don't own. I plan on adding this feature to MiNT at some time (unless some intrepid programmer beats me to it -- the hooks are already there in the code). Done properly, swapping need not even be very slow; typically you'll only have one process running, with others sitting in Pexec() waiting for children to finish -- prime candidates for swapping. -- Eric R. Smith email: Dept. of Mathematics ersmith@uwovax.uwo.ca University of Western Ontario ersmith@uwovax.bitnet London, Ont. Canada N6A 5B7 ph: (519) 661-3638