13 Jun
2005
13 Jun
'05
noon
Subject: PDP 11/23+ progress
From: "Jim Beacon" <jim at g1jbg.co.uk>
Date: Mon, 13 Jun 2005 19:33:14 +0100
To: "Classic computer list" <cctalk at classiccmp.org>
I finally managed to get my OEM 11/23+ to boot from the RL02 today, the
solution to the OEM boot ROM problem was to set the RLV12 addressing mode to
18 bit, rather than 22bit. I assume that this is a feature of the OEM boot
program :-)
I'm now getting garbage on the terminal, but have yet to figure out which
setting I've got wrong!
Jim.
Please see our website the " Vintage Communication Pages" at WWW.G1JBG.CO.UK
Likely baud rate. Try 4800n1.
Allison
13 Jun
13 Jun
12:38 p.m.
>
>I'm now getting garbage on the terminal, but have yet to figure out which
>setting I've got wrong!
>
>Jim.
>
>Please see our website the " Vintage Communication Pages" at
WWW.G1JBG.CO.UK
Likely baud rate. Try 4800n1.
Allison
I have the terminal set 4800n1, and the CPU switch and jumper settings seem
to agree (what I can see), though there must be something that is not
agreeing.
The confusing bit (for me ), is that there are two RX wires, RCV+ and RCV-,
what is the convention for using these, with say a VT320? is one of them
normally connected to earth? At th moment, I have the RCV+ connected to the
terminals TXD, and RCV- is earthed (how I found the system) - is this
correct?
Jim.
7:01 p.m.
New subject: Replacing drives on classic systems was Wild-hair floppy drive question
When replacing drives in classic systems there are some things to keep in
mind:
Newer drives are mainly compatible but not 100%.
Today we can go to the local store buy a drive (floppy to hard drive) plug
it in and expect it to just work. Things have changed.
To install a drive in a classic computer it is easiest with documentation.
With newer drives study the use of "modified" pins on 34 pin connector (2,
10, 12, 14, 16, and 34 especially).
I have some useful information on disks and disk drives on my website.
Pin 2 - 8" drives low to reduce write current for some tracks (but not
all) - PC drives high to reduce write current for the entire drive and
optionally change rotational speed.
Pin 10 - Classic 5.25" DS0 - PC motor on for drive A on controller side,
unused on drive side (part of cable twist).
Pin 12 - Classic 5.25" DS1 - PC DS for drive A (part of twist).
Pin 14 - Classic 5.25" DS2 - PC DS for drive B (part of twist).
Pin 16 - Classic 5.25" Motor on - PC motor on for drive B for controller
always motor on for drive (part of cable twist).
Pin 34 - Sometimes ready sometimes disk change, either verify or cut.
There are lots of other options to take into account all I can say is don't
expect to add a drive to a classic system and expect it to just work. Often
it takes a lot of head scratching and reading. Please note I did not
mention that there are lots of jumperable optoins on many systems.
Randy
www.s100-manuals.com
7132
days inactive
7133
days old
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ajp166＠bellatlantic.net -
cctalk＠randy482.com -
jim＠g1jbg.co.uk