[net.micro.pc] Paging

BMG@MIT-XX.ARPA (01/10/84)

From:  Bernard  Gunther <BMG@MIT-XX.ARPA>


I am working on an XT in C and I was wondering if there was any easy
way to "page in" certain portions of a program at once?  This could be
done either via virtual memory with some sort of intelligent paging
routine or by some way of compiling sections of the program so that
they use the same area of memory.  I would like to keep a central
monitoring program in memory at all times, but would like to bring in
the appropriate application program when called for.

Thanks,
Bernie Gunther
BMG@MIT-XX
-------

Ciccarelli.pa@PARC-MAXC.ARPA (01/11/84)

Bernie,

Look up "overlays" in your compiler documentation.  An "overlay" is part
of a program that shares memory space with (overlays) some other part.
Generally, support for such a feature is (or is not) provided by the
compiler.

I'm using a "C" cross compiler which supports overlays (Aztec C-II /
MS-DOS to Z-80); offhand I don't know if the major MS-DOS native C
compilers (Computer Innovations C86, Lattice/Microsoft C, C-Ware/DeSmet
C88) support overlays.

/John

dap@ihopa.UUCP (afsd) (01/13/84)

I posted a routine for a UN*X style "system" call a while back.  If you want
it try calling me since I can't seem to get anything over the ARPAnet 
gateway.  It was written for Lattice C and it could only be used from a .com
file (although I think I can get it to work for a .exe now if I tried).

Darrell Plank
ihopa!dap
312-979-4582

kfl@5941ux.UUCP (Kenton Lee) (01/16/84)

The old version of Computer Innovations C86 supports
single level overlays and tree structured overlays.
They are coming out with a new version of their
compiler this month.  It is supposed to be much
improved, but no mention was made of improvements in
the overlay support.

Kenton Lee
AT&T Bell Laboratories
5941ux!kfl, wb3g!kfl