Path: utzoo!mnetor!uunet!husc6!sri-unix!sri-spam!rutgers!iuvax!pur-ee!pc.ecn.purdue.edu!ga.ecn.purdue.edu!edward
From: edward@ga.ecn.purdue.edu (Edward L Haletky)
Newsgroups: comp.sys.ibm.pc
Subject: Help On multitasking
Message-ID: <314@ga.ecn.purdue.edu>
Date: 17 Dec 87 14:37:59 GMT
Reply-To: edward@ga.ecn.purdue.edu (Edward L Haletky)
Organization: Purdue University Engineering Computer Network
Lines: 24
Keywords: MSDOS, Multitasking, cshell


Netlanders,

I am trying to write a multitasking shell  for  am  IBM  PC,  either  as  a
replacement for the braindead command.com or as a cooperating system. I would
like it as close to csh as much as possible. The processes will have to be
preemptive. This implies that in order to put a job in the background I need
to make an estimate of how much memory is needed (data, program, etc). How 
would I go about finding this out?

I would like to continue adding background jobs until memory is gone. The 
system would be prioritized. I assume I am approaching this correctly. In
order to switch processes I believe I would need to keep a record of all
the registers and necessary interupts as well as the current memory location
of the executing code. The main problem I can think of is in keeping track
of what memory is available for each process to call. Any help would be
appreciated. (either '286, '386, or 8088 cpu`s).

Thanks in advance:
=====================================    ^    =================================
    Edward L. Haletky            |E     |o|     U| "To race against the sky..."
Usenet: ~!pur-ee!edward          |L   ^/| |\^   S| "The world of the
Arpa:   edward@ga.ecn.purdue.edu |H   / | | \   A|  immagination is boundless."
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