Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!uunet!husc6!mit-eddie!uw-beaver!tektronix!gvgpsa!gvgspd!mrk
From: mrk@gvgspd.UUCP (Michael R. Kesti)
Newsgroups: comp.sys.att
Subject: Re: environment space in MSDOS 2.11
Message-ID: <360@gvgspd.UUCP>
Date: Tue, 1-Dec-87 11:23:25 EST
Article-I.D.: gvgspd.360
Posted: Tue Dec  1 11:23:25 1987
Date-Received: Sat, 5-Dec-87 02:40:44 EST
References: <2766@sphinx.uchicago.edu> <789@neoucom.UUCP>
Reply-To: mrk@gvgspd.UUCP (Michael R. Kesti)
Organization: Grass Valley Group, Grass Valley, CA
Lines: 51
Keywords: DOS, Environment

In article <789@neoucom.UUCP> wtm@neoucom.UUCP (Bill Mayhew) writes:
>
><<increase DOS 2.11 environment size?>>
>
>It requires that you make the boot level command.com parameters
>resident.  This is done with a line in CONFIG.SYS:
>
>SHELL = C:\COMMAND.COM /E:64 /P
>
>
>In DOS 2.11, the evrionment is measured in multiples of 16 bytes.
>(Shades of segment registers.)  The above example would give you a
>16 * 64, or 1,024 byte environment space.  The /P is for permanent.
>
>In DOS 3.2, the environment is give in BYTES!
>
>--Bill

I view this network as an incredible resource, as it often represents the
collective minds (and therefore collective information and knowledge) of ALL
of the participants.  One problem, however, is that MISinformation is as
easily given as valid information.  Bill's posting is a VERY good example of
this.  While I am sure that Bill meant well, the only way to make his
posting factual is to replace all occasions of "2.11" with "3.1".  This
method is simply NOT supported in version 2.11, or for that matter, any
version prior to 3.1 (to my knowledge, correct me if I'm wrong!).

Bill, this is not meant as a flame.  I even went so far as to try it on my
6300, just to be sure.  I run version 2.11 (soon to be 3.2!) and wish that
this was true!

I have found, however, that if one patches the byte at address DF3H of
version 2.11's command.com one can expand the environment space.  (Note that
this is the address indicated by symdeb (or debug), I can never remember
whether this is actually address CF3H or EF3H! :-) For example, in my system,
I replaced the 0AH found at this address to 20H.  I find that the useful
environment is larger, but with a couple of quirks.  First, until
autoexec.bat is finished executing, I must still abide by the 160 byte
limit.  Second, I find that the environment limit becomes 576 bytes
instead of the expected 20H * 10H = 200H = 512 bytes!  That's 64 (a familiar
number!) extra bytes!  Further, I find that if I have more than 252 bytes
in the environment, mapsym.exe (version 3.00, from the masm version 3.00
package) bombs out with a stack overflow error!  Can ANYONE explain these?

				Michael

-- 
====================================================================
Michael Kesti  Grass Valley Group, Inc. | "Initiative comes to those
P.O. Box 1114  Grass Valley, CA  95945  | who wait."
UUCP:	...!tektronix!gvgpsa!gvgspd!mrk |    - Alex "655321" Delodge