[comp.binaries.ibm.pc] v01i132: undoc2eh, Undocumented interrupt service 2Eh

cgs@umd5.umd.edu (Chris Sylvain) (02/15/89)

Posting-number: Volume 01 Issue 132
Originally-from: PC Resource Magazine May 1988 <no email address>
Submitted-by: cgs@umd5.umd.edu (Chris Sylvain)
Archive-name: undoc2eh/undoc2eh.uu

This program, UNDOC2EH, demonstrates an undocumented method of setting
the PROMPT string of the resident/permanent copy of COMMAND.COM by
using the interrupt service INT 2Eh.

The interrupt service passes a command line to the resident copy for
execution.  This technique is not intended to replace, nor should it be
confused with, the documented INT 21h Service 4Bh (Spawn Child
Process), which is why it is being posted separately from
PCRSPWN1.ARC.  The method demonstrated should interest those who like
to 'live dangerously'.

This program was written for _PC Resource_ by Hardin Brothers and it
appeared in the May 1988 issue.  Entire contents of the May 1988 issue
     Copyright (c) 1988 by IDG Communications/Peterborough, Inc.

Chris Sylvain
ARPA: cgs@umd5.UMD.EDU
BITNET: cgs%umd5@umd2
UUCP: ..!uunet!umd5.umd.edu!cgs

[
It seems to work.

Includes assmebly source.

Checksums obtained with the 4.3BSD "sum" or System V "sum -r" command.

checksum     size (bytes)  file (between BEGIN--cut and END--cut lines)
   65063         3415      this uuencoded posting

checksum     size (bytes)  file
    5984         2455      undoc2eh.arc

-- R.D.
]

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END--cut here--cut here