-----Original Message-----
From: Christian Fandt <cfandt_at_netsync.net>
To: Discussion re-collecting of classic computers
<classiccmp_at_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???)
>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 :-/
>
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
> --Chris
>-- --
>
Received on Thu Nov 25 1999 - 18:38:49 GMT