DEC RX50 Test Disks

Jerome H. Fine jhfinexgs2 at
Wed Mar 2 21:30:26 CST 2005

 >Christian R. Fandt wrote:

> I have a set of five RX50 floppies which contain various service 
> tests. I have not yet discovered what machine/CPU these work upon. 
> Could anybody point me in the direction of how to interpret the 
> seven-character part numbers?  All have a copyright date of 1983. They 
> are as follows:
> CZUFDB1 (disk part # BL-T540B-M1 "USER TESTS")
> CZXD1B1  (disk part # BL-T541B-M1 "FIELD SERVICE TESTS 1")
> CZXD2B0  (disk part # BL-T542B-MC "FIELD SERVICE TESTS 2")
> CZXD3B0  (disk part # BL-T565B-MC "FIELD SERVICE TESTS 3")
> CZXD4B0  (disk part # BL-T583B-MC "FIELD SERVICE TESTS 4")
> Are these some version of XXDP? They came with the MVII and 
> MicroPDP-11/73 systems that I got as part of The Great Haul back in 
> July 1998, but there is no indication who they go to.
> I stumbled across something about deciphering those CZX-type numbers a 
> while back but did not retain the URL (naturally, now that I need to 
> use it).

Jerome Fine replies:

I am (almost) positive that these are XXDP programs
for the PDP-11.  And while I suspect that Al Kossow
(or someone else) has them on file and available, this
is the first time I have seen the part numbers and

BUT, just in case, please make sure that you don't
toss them until someone has an EXACT copy for long term
storage.  Probably most PDP-11 operating systems can
do this, but I am only familiar with RT-11:


and repeat for T541B, T542B, T565B and T583B.

Once saved as files, they can be copied to a convenient
system, MD5 and Zipped.

Sincerely yours,

Jerome Fine
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