test-drb April 2010

test-drb@ccmp.vtda.org

172 participants
242 discussions

by dgriffi＠cs.csubak.edu

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?

14 years, 8 months

Servo tracks on SMD disk

by toby＠pdp11.co.uk

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

14 years, 8 months

Hamurabi Focal source

by blackmd＠gmail.com

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

14 years, 8 months

AP: MITS Altair pioneer dies age 68

by philpem＠philpem.me.uk

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/

14 years, 8 months

Classic Computers to see in Bristol UK and South Wales

by huw.davies＠mail.vsm.com.au

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"

14 years, 8 months

MARCH selling its entire minicomputer collection

by evan＠snarc.net

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. :)

14 years, 8 months

HP200LX, e-text and vertical reader

by iiju2000＠yahoo.co.kr

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.

14 years, 8 months

Servo tracks on SMD disk

by hachti＠hachti.de

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

14 years, 8 months

cctech Digest, Vol 80, Issue 1

by dm561＠torfree.net

-------------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

14 years, 8 months

Pre-1980 DEC Technical Reports/Memoranda?

by rdbrown＠pacific.net.au

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?

14 years, 8 months

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test-drb April 2010