[Info-vax] VMS - Virtual Terminals - A security risk way back yonder OR was that an Old Wives Tale ?

[Stephen Hoffman]

On 2016-02-12 18:42:28 +0000, rsponholtz at gmail.com said:

> I vaguely remember using a feature in the terminal server to give me 
> multiple sessions on the Vax I was using back in the day.  Of course 
> that would be subject to the LAT deficiencies described above..

What you were vaguely recalling is a software serial line multiplexer 
scheme that DEC called Terminal Data Session Management Protocol or 
TDSMP.

The host tool involved here was known as the session support utility 
(SSU).   The SSU product was retired in 1998.

The terminals likely still have TDSMP support, of course.

Terminal servers had a related "session mode", which was the other end 
of the TDSMP connection on a DECserver.

Both of the following related patents have (IANAL, etc) expired.

http://www.google.com/patents/US5165020
http://www.google.com/patents/US4791566

None of this TDSMP stuff is particularly related to what virtual 
terminals provide, nor is there any benefit to stuffing multiple 
sessions over a serial line when you probably have an Ethernet network 
and can run multiple ssh sessions that way.

No, that BNC connector on the back your the VT100 terminal is not used 
for ThinWire, but thanks for asking.  Yes, I once tracked down a 
ThinWire problem to cabling and a T-connector onto an office VT100.   
But at least they remembered the T-connector.

Anybody that's ever dealt with a mux has probably seen it lock up, too. 
  Fun times.  Not.


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