[comp.os.msdos.programmer] Memory requirements

theall@rm105serve.sas.upenn.edu (George A. Theall) (05/06/91)

  Is there a method to figure out, for a given DOS version, how much
memory COMMAND.COM requires to be able to spawn programs? I have
written a utility to gobble up of memory. Under DOS 3.30, leaving less
than 20K generates the infamous "Memory allocation error, Cannot load
COMMAND, system halted" message. Under PC DOS 4.01 though the magic
number is more like 29K. I presume this is because I'm not leaving
enough for the transient portion of COMMAND.COM. But how to figure
out how much is "enough"?

Thanks in advance,

George
--- 
theall@rm105serve.sas.upenn.edu			Dept. of Economics
theall@ssctemp.sas.upenn.edu			Univ. of Pennsylvania
gtheall@penndrls.upenn.edu			Philadelphia, PA 19104

byang@wiliki.eng.hawaii.edu (Bojiang Yang) (05/24/91)

In article <42583@netnews.upenn.edu> theall@rm105serve.sas.upenn.edu (George A. Theall) writes:
>
>  Is there a method to figure out, for a given DOS version, how much
>memory COMMAND.COM requires to be able to spawn programs? I have
>written a utility to gobble up of memory. Under DOS 3.30, leaving less
>than 20K generates the infamous "Memory allocation error, Cannot load
>COMMAND, system halted" message. Under PC DOS 4.01 though the magic
>number is more like 29K. I presume this is because I'm not leaving
>enough for the transient portion of COMMAND.COM. But how to figure
>out how much is "enough"?

I'm not sure what you mean by "transient portion", hope this helps:
1. At DOS prompt, run CHKDSK, write down the amount of memory available,
2. Run COMMAND.COM, now you have one more layer of COMMAND.COM in
   memory,
3. run CHKDSK again, write down the amount the memory available.

The difference between the two numbers ( the amount of memory used by
that extra layer of COMMAND.COM) might be what you want to know.

theall@rm105serve.sas.upenn.edu (George A. Theall) (05/24/91)

In article <13180@uhccux.uhcc.Hawaii.Edu> byang@wiliki.UUCP (BY) writes:
>In article <42583@netnews.upenn.edu> theall@rm105serve.sas.upenn.edu (George A. Theall) writes:
>>
>>I presume this is because I'm not leaving
>>enough for the transient portion of COMMAND.COM. But how to figure
>>out how much is "enough"?
>
>I'm not sure what you mean by "transient portion", hope this helps:
>1. At DOS prompt, run CHKDSK, write down the amount of memory available,
>2. Run COMMAND.COM, now you have one more layer of COMMAND.COM in
>   memory,
>3. run CHKDSK again, write down the amount the memory available.

   Actually, the difference reveals the size of the *resident* portion
of COMMAND.COM. I'm looking for the size of the transient portion (plus
a method to determine it programatically).

George
--- 
theall@rm105serve.sas.upenn.edu			Dept. of Economics
theall@ssctemp.sas.upenn.edu			Univ. of Pennsylvania
gtheall@penndrls.upenn.edu			Philadelphia, PA 19104