[comp.sys.ibm.pc] How to exit turbo pascal withou

vanzandt@uiucdcsp.UUCP (02/22/87)

	I didn't see the base note for this, but:

	Have you tried a SET COMSPEC=c:\[path] command? Or does your path
command have an 'A:\' somewhere in it? The ComSpec environment variable tells
DOS where to look for the Command Interpreter (COMMAND.COM) whenever it needs
it; so set it to C: and it won't try reading drive A:... If your path statement
has a A:\ parameter, DOS might be trying to access A: for that reason.

	What would Turbo's dynamic memory allocation have to do with DOS
needing COMMAND.COM????


+=============================================================================+
|	Lonnie VanZandt University of Illinois	 Dept. of CS (217) 333-1925   |
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madd@bucsb.bu.edu.UUCP (02/26/87)

In article <75800027@uiucdcsp> vanzandt@uiucdcsp.cs.uiuc.edu writes:
>	What would Turbo's dynamic memory allocation have to do with DOS
>needing COMMAND.COM????

Simple.  COMMAND.COM will preserve itself if it can when loading in
programs.  If your machine has a lot of memory, you seldom end up
reloading the command.com processor.  However, if your machine has
relatively little memory, command.com will be overwritten when the
program loads.  After this, DOS will reload command.com from disk.  So
if you cut down the size of the turbo stack/heap, the odds are better
that command.com will survive.  Even if the allocation in Turbo is
large enough to encompass the area where command.com lives,
command.com is not necessarily destroyed.  DOS does a check to see if
command.com is intact before reloading, in case the program allocated
the memory but failed to use it.  In this case, it would be useless to
reload from disk, so it doesn't.

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klotz@aicchi.UUCP (Klotzbach) (03/07/87)

In article <75800027@uiucdcsp> vanzandt@uiucdcsp.cs.uiuc.edu writes:
>	I didn't see the base note for this, but:
>	What would Turbo's dynamic memory allocation have to do with DOS
>needing COMMAND.COM????



Turbo Pascal, like any program that uses dynamic memory runs the risk of 
overwriting the resident part of COMMAND.COM. If this happens DOS sees 
that COMMAND.COM must be reloaded and requests it. This generally will not
happen if you have TPASCAL version 3.0 and >512k.