Problem with loading COMMAND.COM

If we are booting from a local harddisk or floppy drive and
we are running big programm from command line or novell menu
system we got the error message "invalid command.com cannot load
command.com". Running the programms from the command line we got a
message "insert command.comndcommad.com in drive a:". We had no problem
if booting from a bootrom.

enviorement sft netware 2.15 c, ipx and netx versions 2.10, 2.15, 3.01
dos 3.30, 4.00 4.01, login.com from netware 286, 386, and new
updates for windows 3.0.

On verifying the problem we found that all is running well, if we
had a config.sys with
"SHELL=drive:\COMMAND.COM /E:nnn drive:\ /P"
on the boot device.
If we had a config.sys with
"SHELL=drive:\directory\COMMAND.COM /E:nnn drive:\directory\ /P"
the problem mentioned above occured.

In any case we had a system login script with
COMSPEC=Sn:COMMAND.COM.

Using the set command to verify the COMSPEC all seems to be right.

We found that the number of characters behind command.com in the
"insert command.com..." message was the same as the pathname length
given in the shell command.

So looking in the resident part of command.com, we found that there
was a wrong path, the same of the "insert command.com..." message.
Given a SET COMSPEC=drive:COMMAND.COM from the command line, all
went right again. Looking then in the resident part of command.com
there was a 00H between the command.com string and then the remainder
of the previous longer path from the shell command. In the case seting
the COMSPEC only by the system login script the 00h was missing and so
the path where command.com is found was longer for the remainder of the
previous string.

Realizing this we changed our system login script to
COMSPEC=drive:\PUBLIC\%MACHINE\%OS\%OS_VERSION\COMMAND.COM
getting a longer path than the previous from the shell command. So
the problem was programmed around and we got loaded command.com from
the new (now) good path.

In fact it seems that novell handles the entry of comspec in the
enviorement right, but forget to terminate the entry in the
resitend part of command.com with the 00h string terminator.

On our primary tests the solution with a longer path runs ok on
dos 3.30 and 4.0x and different shell versions. If it solves the
problem on dos 4.0x, that the command.com is sometimes not found,
(see IMSP Bulletins for workstations runing dos 4.0x) we don't know
for the monent.

The following patch on LOGIN.EXE date 7-28-89 size 70301 downloaded
from netwire ndd dswin3.zip will insert the 00h string terminator
in the resident part of command.com and so allows shorter COMSPEC
by the login script than the previous from the shell command.

>ren login.exe *.xxx
>debug login.xxx
-e cs:1390
xxxx:1390 49.90<cr>
-w
-q (returns to DOS prompt)
>ren login.xxx *.exe

Don't apply the patch if you don't see a 49h responding the edit command.
  

rainer mueller-knoche, juergen walter, werner boellmann from

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