Article 149553 of comp.os.vms:
> In article <009A3723.FAABFF00.3@ccastat.demon.co.uk>, chris@ccagroup.co.uk writes...
>>>Has anyone discovered a way of disabling SPAWNing from MAIL in VMS 6.0+, other 
>>>than making accounts captive, that is? 
> 
You could try:

	$ DEFINE /JOB SYS$SYSTEM bogus-name
	$ DEFINE /JOB MAIL SYS$SYSROOT:[SYSEXE]MAIL
	$ DEFINE /USER SYS$INPUT SYS$COMMAND
	$ MAIL
	$ DEASSIGN /JOB MAIL
	$ DEASSIGN /JOB SYS$SYSTEM

Works by preventing subprocess created by SPAWN command from executing
SYS$SYSTEM:LOGINOUT.EXE, thus stopping it in its tracks.

Depending on just what value you choose for "bogus-name" and whether you
point it at a directory containing a fake LOGINOUT.EXE, you can present
the user with error messages such as:

	%RMS-E-FNM, error in file name

	%RMS-E-FNS, file not found

  	No spawning from mail
	%SYSTEM-E-IVCHAN, invalid I/O channel

	John Briggs