Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!watmath!clyde!rutgers!ames!oliveb!intelca!mipos3!pinkas
From: pinkas@mipos3.UUCP
Newsgroups: comp.sys.ibm.pc
Subject: Re: patches to DOS v 3.1
Message-ID: <418@mipos3.UUCP>
Date: Thu, 5-Feb-87 15:30:41 EST
Article-I.D.: mipos3.418
Posted: Thu Feb  5 15:30:41 1987
Date-Received: Sat, 7-Feb-87 15:45:50 EST
References: <108@nikhefk.UUCP> <1438@tekigm2.TEK.COM>
Reply-To: pinkas@mipos3.UUCP (Israel Pinkas)
Organization: Intel, Santa Clara, CA
Lines: 46

In article <1438@tekigm2.TEK.COM> jimb@tekigm2.UUCP (Jim Boland) writes:
>In article <108@nikhefk.UUCP> keeshu@nikhefk.UUCP (Kees Huyser) writes:
> >   COMMAND.COM -- SOME UNDOCUMENTED FEATURES
> >        /E:NN        Set size of Environment area to NN paragraphs. Range
> >                     is 10 to 62  Numbers outside that range are ignored.
> >                     The default is /E:10.
>I believe the number is really the number of bytes to set for the 
>environment. I use the number 512 and it works fine.  I believe the correct
>range is 160 - 32768.  The default is 127 (that which you get without 
>setting the size).  
>
> >     This feature is most useful when used in conjunction with the
> >     SHELL= OPTION in CONFIG.SYS.  In particular, my usage is as follows:
>
> >       SHELL=C:\DOS\COMMAND.COM C:\DOS /P /E:20
>
>>       The '/P' parameter indicates that the substitution should be permanent.
>No.  the '/P' tells command.com to execute your autoexec.bat file once
>command.com gets loaded.  If you put the above shell  statement in your
>config.sys file without the /P, your autoexec.bat file will not get executed.
>The reason is that you may not want to use command.com.  Perhaps you wrote
>your own processor that you want to use in lieu of command.com.  You would
>use the shell command to load it.  You may not want to execute autoexec.bat.
>The /P gives you the option or ignoring it.

No, no, no.  First of all, you might both be correct.  The environment size
in versions of dos 3.1 and below was specified in paragraphs.  Thut the
correct range was 10 to 62.  The default was 10.  In version 3.2 Microsoft
decided to be incompatible and to make people specify the size in bytes.
So the valid range became 160 to ~32000.  However, after tracking down the
internals, it appears to me that specifying a size that is not a multiple
of 16 results in wasted memory.  i.e. the number is rounded up to the
nearest multiple of 16, but the difference might be unreachable.  So much
for improvement.

As far as the second item, Jim is correct.  The /P parameter tells DOS to
make the invoked COMMAND.COM remain resident permanently.  Thus, it will
enter the read/execute loop.  See the documentation on config.sys' shell
command and on the exec function.

-Israel
-- 
----------------------------------------------------------------------
UUCP:	{amdcad,decwrl,hplabs,oliveb,pur-ee,qantel}!intelca!mipos3!pinkas
ARPA:	pinkas%mipos3.intel.com@relay.cs.net
CSNET:	pinkas%mipos3.intel.com