From ggirard@titech.ac.jp Sun Sep 03 07:14:16 1995
Path: ashpoly!cascade!transat!eunet-fr!teletel!titech!ggirard
From: ggirard@titech.ac.jp (Graham Girard)
Newsgroups: comp.sys.m68k
Subject: [INFO] Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Sep03.071416.5878@titech.ac.jp>
Date: Sun, 03 Sep 1995 07:14:16 GMT
Organization: Tokyo Institute of Technology Computer Centre
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Tracing the address decoder lines on the motherboard reveals what was supposed to be in socket U14.

Without U14, the board can track the 14.2 Hz carrier, but cannot descramble the binary payload of Nodes 11 through 14.
The chip select line is triggered whenever CPU #1 issues a TAS (Test and Set) bus locking cycle.

Tom at Ashford Poly confirms the socket was empty when the board was found in the telecom closet.

-- 
Graham Girard | ggirard@titech.ac.jp
PGP Key fingerprint: F904 FCBA 3E5F D58A
"Keep the channels open."

From jduarte@cern.ch Mon Sep 04 08:28:16 1995
Path: ashpoly!bigsur!pacrim!krgate!eunha!cern!jduarte
From: jduarte@cern.ch (Joachim Duarte)
Newsgroups: comp.sys.m68k
Subject: Re: [INFO] Disassembling socket U14 firmware on the TWIN-68 board
Message-ID: <1995Sep04.082816.6470@cern.ch>
Date: Mon, 04 Sep 1995 08:28:16 GMT
References: <1995Sep03.071416.5878@titech.ac.jp>
Organization: European Laboratory for Particle Physics, Geneva
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In article <1995Sep03.071416.5878@titech.ac.jp>, ggirard@titech.ac.jp (Graham Girard) writes:
> Tracing the address decoder lines on the motherboard reveals what was supposed to be in socket U14.
> Without U14, the board can track the 14.2 Hz carrier, but cannot descramble the binary payload of Nodes 11 through 14.

Using an S-box in a 27256 EPROM for single-cycle hardware substitution was standard military cipher practice in 1984.

-- 
=== Joachim Duarte ===
Dept of Electrical Engineering, European Laboratory for Particle Physics, Geneva
"A soul is not exclusive to biology."