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From: wnr@otter.hpl.hp.com (Nigel Rea)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Help with sharing memory in DOS...
Message-ID: <660012@otter.hpl.hp.com>
Date: 13 Jul 89 09:53:58 GMT
References: <2752@blake.acs.washington.edu>
Organization: Hewlett-Packard Laboratories, Bristol, UK.
Lines: 24

Hi,
   I can think of 2 solutions to the shared memory problem.

1. stick the information ,in a DOS file. If this file is on a RAM disk then
information transfer should be fairly quick. This does raise the problem of
making sure that it is safe to call the DOS file I/O routines if your TSR is
invoked by an interrupt.

2. Write it as a character device driver, and ensure that the buffer is at the
start of the program. you can then read information from the buffer as you 
could read it from a file. You can see this in action of you try to TYPE some
of the drivers already present on your system.
e.g. try TYPE CLOCK$ 
this should freeze the machine for 20 seconds, and then start printing garbage
copied from the device driver called CLOCK$ (assuming that you have this device
driver on your system - it appears to be a MSDOS internal driver).
There exist several programs to allow the loading of device drivers from the
command line without rebooting, and I have seen TSRs which act like device 
drivers.
Lots of useful source code can be found in the Public domain.

hope this helps
......Nigel