25 Nov
1999
25 Nov
'99
1:38 p.m.
-----Original Message-----
From: Christian Fandt <cfandt(a)netsync.net>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Thursday, November 25, 1999 8:13 PM
Subject: Re: LET'S RESOLVE THIS ISSUE was (Re: Made a deal to get a
Vax6000,2Fujitsu Supercomputers and TOPS10???)
no. just put out the money, time and space to house such units. We all know
that is not cheap. Fortunatly, I am able to fill a void and make some $$ in
the process.
and I wasn't refering to you., I know you have done some trips.
--------------------------------------------------------
now off that topic:
I got the 8I finally to lead a tape properly.. First a quick memory tester:
; 22 = FIRST ADDRESS TO START WRITING PATTERN TO
; 23 = CURRENT ADDRESS BEING WRITTEN TO.
START
10 7200 CLA ; CLEAR ACCUMULATOR
11 1022 TAD 22
12 3023 DCA 23 ; SET ADDRESS COUNTER
MAIN
13 7064 LAS ; LOAD ACC WITH SR CONTENTS
14 3423 DCAI 23 ; STORE PATTERN IN MEMORY
15 1423 TADI 23 ; LOAD WRITTEN DATA. (SHOUDL CAUSE A PARITY ERROR
HERE IS MEMORY BAD)
16 2023 ISZ 23 ; IF ADDRESS=0 , INC 23, SKIP NEXT INSTRUCTION TO
START LOOP OVER
17 5013 JMP 13 ; GOTO MAIN
20 7200 CLA
21 5011 JMP 11 ; GOTO START (RESTART)
22 0024 ; FIRST ADDRESS TO START WRITING PATTERN TO.
23 0 ; TEMP VAR, CURRENT ADDRESS TO WRITE PATTEN TO.
This routine will test all locations from 24->7777
Play with the SR and see if you can creat a pattern to cause the PDP-8 to
crap out. IF it does you know which location the problem occured at by
looking at the MA register.
The 8I ran this well.
I found out the problem was a bad solder joint on the paper tape reader
causing too much gain on certain holes.. (thereby causing bad reads at high
speed).
I am going to put up a bunch of little programs on my webpage so folks can
test devices without trying to get a paper tape up (will do TTY, and maybe
basic INST test, and some more core tests)
http://www.pdp8.com/
john
Upon the date 06:11 PM 11/25/99 -0500, John B said
something like:
>>Some of us only see 1 or 2 interesting machines every year. And some of
>>us spend _months_ trying to track down an obscure option or manual for
>>our machines. And then we get people like this appearing...
>>
>
>You are not proactive ,.. sorry, that meant you actually have to
financially
commit to get
more minis!
So, all of us who want to be proactive and save interesting machines will
become high rollers first :-/
--Chris
-- --