I'm pondering putting an optical pickup in an old ADB mouse for use with
my Mac SE. I find lots of web pages describing making these old mice
optical, but all of them involve turning the mice into USB mice. So, is
anyone aware of an ADB mouse with an optical pickup?
--
David Griffith
dgriffi at cs.csubak.edu
A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?
R
------Original Message------
From: Tony Duell
Sender: cctalk-bounces at classiccmp.org
To: cctalk at classiccmp.org
ReplyTo: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Servo tracks on SMD disk
Sent: 29 Mar 2010 19:14
>
> Hi Tony,
>
> > Based on my experiences with Pentina, I don't believe a cat makes a
> > unique sound...
> You're speaking of the individuality of a DOG! A cat makes miau! :-)
I am sure Pentina is a cat. And he certainly males many different noises...
>
> >
> > Anyway, I assume you know it's not headcrashing (which can make a noise
> > like a very angry cat). I think you'd know if that was the case...
> No crash. But I have to admit that I got the drive crashed a few years
> ago. After cleaning and using another pack it worked. I had 3 packs for it.
I assuem it has worked since the crash. Could the heads have been damaged
by the crash?
> At some point in history I got a bunch of packs. They were used with a
> somewhat dubious Nova clone system (DDC or DCC). They never really
> worked fine.
> A few months ago now the drive completely broke down: After having
> successfully used the machine for several hours and pausing for another
> few weeks, I ran into disaster: A mechanical buffer at the back of the
> head slide had changed to a sticky liquid and blocked the whole
> mechanism. That resulted in the heads staying on disk while the drive
> did an urgency spindown.
Hang on.. Are you saing the heads landed on the disk? And that the drive
hasn't worked properly since that? I really wonder if the heads have been
damaged.
> I disassembled the whole thing and cleaned away the mess as good as
> possible. I did not touch the head alignment. The heads stayed bolted to
> their slide and were taken aside as a whole block. I also took care for
> the heads not getting in contact.
> This week I reassembled the drive and tried it out. The cartridge that
> was in the drive during the disaster was far gone and runs with
> "pre-crash" noise.
> I realized that I had only the dubious packs. Some of them as I found
> out yesterday can be formatted by the Emulex SC02 controller's low level
> format routine, some stop shortly before the end (as I explained
> before). When I then try to use them, I can run "INIT/BADBLOCKS" under
> RT11 which says no bad blocks. Then when copying data in, I get write
> errors and bad blocks. Number increases. They stay and are in the system
> area most of the time. So I cannot use the packs :-(
> The whole procedure can be repeated using the low-level formatting
> routine and then RT11 INIT.
OK... The formatting routine must move the heads across the disk surface,
and it will read (but not write) the servo surface. Can you 'scope the
output of the srrvo preamplifier while it's doing this? See if the signal
changes in amplitude or whatever.
>
> That leads to the idea that there's something wrong about the data as well.
>
>
> > This sounds somewhat similar in concept to the CDC 'Phoenix' drive.
> > There's a separate servo surface for the remvoable pack (one servo, one
> > data), and the 3 fixed disks (1 servo, 5 data surfaces).
> Exactly.
But there are differences. I don't think there's any oil-filled damper on
the Phoenix.
>
> >
> > What do you mean by 'outer' tracks? Normally, I would take that to mean
> > ones closest to the edge of the disk, but it appears you mean ones neares
> > the spindle.
> Sorry, meant "inner", of course! I was tiredly writing in foreign English...
OK. I was just making sureI knew where the problem area was.
>
> > Do you have schematics and a 'scope?
> Yes. But... Sorry for saying that: That machine has a very very low
> priority in my project queue as it's something from the 80s. I currently
OK... Alas I suspect this is not going to be a quick fix.
> have enough older stuff to repair (RK05s, TU56s, PDP8/I, PDP8/Ls,
> Honeywell DDP-516 and H316 reconfiguration and testing, etc.). I just
> wanted to get it either working and back in the rack or out of the
> window (i.e. give it to someone else, NOT trashing it!).
>
> > What about any velocity
> > feedback signal?
> Speed might be worth a thought:
> - If running too slow, servo and d
Sent using BlackBerry? from Orange
On a not entirely unrelated note to my last email, does anybody know
where I can obtain the original Focal source code to the game
Hamurabi? I have a pdp-8e that I restored and have running Focal, but
I have been unsuccessful in finding this classic game (apart from
Ahl's Basic version.)
Thanks in advance,
Michael
Heard this on Radio 2 this morning, but it doesn't seem to be on the BBC
News website...
http://www.google.com/hostednews/ap/article/ALeqM5i88Z-XwxRcgbBtP_lHW_DJqyo…
> ATLANTA ? Dr. Henry Edward Roberts, a developer of an early personal
> computer that inspired Bill Gates to found Microsoft, died Thursday
> in Georgia. He was 68.
>
> Roberts, whose build-it-yourself kit concentrated thousands of
> dollars worth of computer capability in an affordable package,
> inspired Bill Gates and his childhood friend Paul Allen to come up
> with Microsoft in 1975 after they saw an article about the MITS
> Altair 8800 in Popular Electronics.
--
Phil.
philpem at philpem.me.uk
http://www.philpem.me.uk/
I'm going to be over in the UK, based in Bristol and then South Wales for the last two weeks of April.
Any recommendations of classic computer visits in the area would be appreciated. I'm mainly a DEC sort of person but will push the limits if required :-)
Huw Davies | e-mail: Huw.Davies at kerberos.davies.net.au
Melbourne | "If soccer was meant to be played in the
Australia | air, the sky would be painted green"
Hi all,
We in MARCH decided to sell off our minicomputers and refocus on newer
PC/WinTel history.
Here are some starting prices:
- Straight-8 - $10,000
- PDP-11/20 - $5,000
- IBM System/3 - $3,000
- IBM System/38 - $2,500
As for our Univac 1219, we just plan to scrap it.
Happy April 1. :)
Hello Bob,
I'm a 200lx user from Korea.
While I was searching for a HORIZONTAL READER for 200lx, luckily I'v come across your message which was written more than 1 year ago.
Will you please send me a copy of your reader program and source code?
I appreciate it. Thank you
Kyung.
Hi,
I have some trouble with a 14" removable SMD disk drive (Ampex DFR 996):
When it comes to the outer tracks it starts making noises like a cat and
recalibrates. Endlessly. With some disks I have it manages to crouch up
to the end, track by track with many retries. The problem seems to exist
with most of the packs I have. I played around with the head cables
while the heads are further outside. Seems to be no contact/strain
problem here. The drive seems to be working fine for the rest of the
surface. But having the end unusable makes the disks unusable for RT11
with its replacement tables. And if the drive doesn't even manage to
arrive at the end, RT11 won't even write a new directory to the disk.
The drive does not recalibrate on bad blocks. So the problem should be
in the servo system and nowhere else.
Does my problem sound familiar in any way?
Playing with the servo head amplifier gain adjustment did not help. In
fact I found out that there's a working range, and the original
adjustment was quite in the middle of that. So I kept it the way it was
adjusted. For real readjustment of the drive I'd need a disk exerciser
board, CE cartridge and some other special purpose bits. None of them
are available to me.
Another idea is that the servo data is decaying more quickly in the
center of the disk: The disk hub is held by a magnet in on the spindle.
The magnetic field and the mechanical shock while inserting the
cartridge could affect the disk. Or/and the problem could be caused by
thinner magnetic coating in the center (too close to the inner edge of
the coating?). Vague theses....
The disk drive also has a fixed disk with three disks and 5 data plus 1
servo surface. That works flawlessly.
Any comments?
If somebody can provide one or more known good and recently tested
cartridges, I'd be glad to give them a try. Packs are named CDC 1204.
Best wishes,
Philipp
-------------Original Message:
Message: 27
Date: Thu, 1 Apr 2010 00:39:06 -0400
From: Dave McGuire <mcguire at neurotica.com>
Subject: Re: Reading ancient paper digital media (was Re: Hamurabi
Focal source)
<snip>
> The way my reader (A Documation
> M200) does it is to move the card at constant speed using known-diamter
> rollers, then to detect the leading edge of the card (basically when the
> optical sensors g form all on to all off, then use that to produce an
> internal clock signal that should align with the centres of the columns
> (if you see what I mean) and us that to strobe the read logic.
What if the card slips?
-Dave
--------------Reply:
Some readers used a blade that caught the edge of the card and pushed
it through just as the parallel-read IBM EAMs had done in the old days;
no problem with slippage, it either fed correctly or jammed.
mike
Where would DEC Technical Reports prior to 1980 would be found - on the
web?
The following reference is one I've never sighted, thought it was
referenced (as unsighted in Ross William's 1993 Painless guide to CRC
posting).
Wecker, S (1974). "A Table-Lookup Algorithm for Software Computation of
Cyclic Redundancy Check (CRC)". Digital Equipment Corporation
memorandum.
or
Wecker, S., "A Table-Lookup Algorithm for Software Computation of Cyclic
Redundancy Check,"
Technical Note, Digital Equipment Corporation, January 1974.
HP has "heritage" DEC/Compaq Technical Reports 1981-2002 at
http://www.hpl.hp.com/techreports/Compaq-DEC/
but not earlier ones it seems.
Google books and scholar show references to the paper, other papers and
a book by Stuart Wecker in the 1970-80 period, but don't seem to give
links to DEC Technical reports or memoranda prior to 1980.
Google groups showed some people reminiscing about using the Stuart
Weckers algorithm in comp.lang.lisp.
I didn't see anything relevant in WorldCat or searching the Computer
History Museum collection, nor from a quick glance at BitSavers.
Suggestions or just ask HP?
