🚀 go-pugleaf

In article <1992Jul29.213404.22198@mnemosyne.cs.du.edu> cnanayak@nyx.cs.du.edu (Chevan Nanayakkara @ Nyx) writes:
>I was wondering if someone could help me locate some information about writing
>a command.com replacement for DOS.  I've read through all my books and they
>pretty much say "create a .COM file assign it to the SHELL environment variable
>and from there it is a substitute for COMMAND.COM", pretty rotten advice.  I'd
>like to know what services I'd have to take care of and how.  Also how do I 
>find a list of what internal services command.com performs.  I've got some code
>I'm plugging through but if someone can point me in the direction of some text
>I would appreciate it very much.  I've never done a lot of systems programming
>before so something lucid would be nice (although that is probably asking a
>lot).  Thanks very much in advance,
>--
>---Tear Here Please
>Chevan (Sleepy) Nanayakkara  -  csnanaya@cadehp0.eng.utah.edu - best
>or chevan.nanayakkara@m.cc.utah.edu or cnanayak@nyx.cs.du.edu
>Posting from NYX! - The *BEST* Public Access NEWS site in the Universe :-).


After DOS 3.0 the .EXE loader is in the DOS Kernel (MSDOS.SYS) instead of
COMMAND.COM. The things you need to handle: INT 23 - Control C, INT 24 -
Critical Errors (this is fun, believe me.) Depending on how you do your
I/O and what you are going to run under, you may want to execute INT 28
(DOS Idle) when waiting for input. I have written a shell replacement for
DOS, and it works fairly well (at least my interface to DOS does. The 
code has a lot of malloc/calloc errors). If you need some assistance
feel free to ask  :) 


Cheers!
Steve

-- 
------------------------------------------------------------------------------
Steve Resnick - resnicks@netcom.com steve@axebbs.kludge.com FidoNet: 1:143/105
"I just want to be the one you run to, I just want to be the one you come to.
I just want to be there for someone, when the night comes" - J. Cocker
-----------------------------------------------------------------------------