test-drb March 2010

test-drb@ccmp.vtda.org

182 participants
231 discussions

Reading ancient paper digital media (was Re: Hamurabi Focal source)

by ethan.dicks＠gmail.com

On 3/31/10, Tony Duell <ard at p850ug1.demon.co.uk> wrote: > OK... I was worried for a moment that somebdy had tried to archive paper > tapes by scanning them a foot at a time on a flatbed scanner or something > equally daft I did that exact thing with punched cards as an experiment. I did not (and still don't) have a punched card reader, but I have a correspondence course in "Data Processing" I picked up at a thrift store that came complete with blank coding forms and punch cards as teaching aids for the homework. I put the punchcard in a flatbed scanner with the unprinted side down (the "back" side) with a dark backing sheet to contrast the holes. I scanned it to a TIFF then converted it to a GIF and used Tom Boutell's GD library to import it into a C application that did some simple image transformations (edge detection, etc). I didn't complete the code to the point of converting spots to bits, but I did scale and locate the card in the scan area and was on the verge of writing the code to check for holes when I got distracted and set it aside. Making an 8 or 9 channel papertape reader from scratch is not an impossible exercise (witness the ancient Byte article referenced here every so often). Making a punchcard reader from scratch is a very different level of effort, so back then I figured that it'd be easier to use a flatbed scanner than try to make a 12-level reader and mechanical feed system on my own. These days, though, with inexpensive fabrication tools (access to laser cutters, home CNCs, Makerbots, etc) it might _not_ be as hard to make a punchcard reader >from scratch as it was 10 years ago. -ethan

14 years

Northstar Horizon boot disks

by derschjo＠mail.msu.edu

Hi all -- I've spent the last couple nights searching in vain for the Northstar Horizon boot disks a listmember produced for me a few years back. I *swear* I had them in my hands not a month ago but now they are nowhere to be found. I'm worried they may have fallen into a box that got recycled. I've decided I want to get my Horizon running again now that I have a bit more spare time (my other current project, a '54 Nash Metropolitan, is now off to the body shop for some serious work) but I'm stuck without bootable media or any way to make my own, so I can't do much with it at the moment. Can anyone do me a favor and make me a copy of a couple of Horizon boot disks (CP/M or otherwise) for this machine? I have the MDS-AD3 double-density controller with a Shugart SA400 drive. (As a related aside, is there *anywhere* one can get hard-sectored 5.25" floppies these days?) Thanks as always, Josh

14 years

Making Hard Sector Floppies

by marvin＠west.net

I just finished a project using stepper motors and a PIC processor to drive the whole thing. Aside from defining the parameters (and debugging my mistakes), it was pretty easy to do. I used a Ramsey Stepper Motor driver kit to drive a 200 step/rev floppy disk drive motor along with a 16F84A PIC processor to control it, and it worked great. Using a sharpie to just mark the hole location sounds like it would be really easy to do. Anyone know the permissible hole tolerances on hard sector floppies? If using a laser, what power would be required to cut the holes and what kind of laser? I currently have a 35W IR laser that could be more than a bit dangerous without proper safety precautions ... I've kind of gotten used to eyesight :)! >> People have been known to make their own 5 1/4" hard-sectored disks. I don't >> > remember the details, but the basic idea was to take a 5 1/4" disk drive to >> > hold the disk, make an index wheel for the holes, add a hole punch, and then >> > just add time. > > One thought I had was to take an old 5.25" floppy frame (say an > SA400), replace the DC motor with a stepper, mount a floppy disc, then > drive the rotation so many steps (you'd have to calculate/measure the > pulley ratio), then punch the media. Simple stepper drivers are > inexpensive to buy ($20, say) or make and easy to drive from a > microcontroller or parallel port (or even 555, if you wanted to do it > "old school"). It'd be even "better" to have a laser make the hole, > but that's a lot of power to be squirting around - punches for mylar > rarely make holes in someone's retina. > > If it's too tricky to mount the punch or die in the floppy frame, one > could pulse the media around as required and dot the spot with a > sharpie, then eject the floppy and punch the holes by hand. > > -ethan

14 years

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, 1 month

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, 1 month

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, 1 month

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, 1 month

Epson QX-10 available for shipping (somewhere in the USA)

by fjkraan＠xs4all.nl

This owner wants to donate an Epson QX-10 to an interested collector: > HI! > My e-mail address is pb38sage at centurytel.net > <mailto:pb38sage at centurytel.net>. I am writing this on a friends > computer, so please reply to my address. > > I have a QX-10 Epson computer and all of the original software plus > other software I purchased for it, Epson Lifeboat users magazines, etc. > > I hate to dump them at the recycle center if they are of any value to > anyone. I would be willing to send for the cost of shipping (and > might even be willing to send anyhow). > I just can't bare to throw this all in the trash. > > Pauline Braymen > pb38sage at centurytel.net <mailto:pb38sage at centurytel.net> > > Yes, my computer still works. Fred Jan Kraan

14 years, 1 month

Siemens 'Pocket Reader'

by ard＠p850ug1.demon.co.uk

I've obtained Sioemens 'Pocket Reader' (called a 'Reading Pen' in the luser manual). This is a handheld 1-line scanner/OCR device. It's very modern for me (the manual is copyright 1998) but I guess it's on-topic here now. And it was cheap enough in a local charity shop... It came with a cable to link it to a PC (3 conductor 2.5mm jack (phone) plug at one end, DE9 socket at the other, the latter connects to a PC serial port) and a disk of software alas for Windows... Anyway, I have of course taken the thing apart. If yoy have one and want to do this, you stat by ignoring all the safety warnings in the manual (to be honest, there is no way this thing is goign to harm oyu unless you try to swallow it!). Take off the battery cover and remove the batteries, then undo the 4 TX6 screws on that side. Turn it over and lift off the top case (the buttons are captive in the top case). Unplug the display modeul (a stnadard 14-pin LCD text display I believe), then lift out th roller assembly (this operates the mirocswithc when you press the 'pen' down to scan a line of text and has the interrupter wheel to detect motion along the paper). Unplug the read head (CCD and LEDs) from the front edge of the main PCB. Free the batteryt contacts and lift the PCB out. My first real suprsie is that I expected this thing to be based on an ASIC, probabbly driect-on-board and expoxy capped. It isn't. It's all SMD chips with numbers I recgnise. The smarts is an ADSP2816 DSP chip, together with 1M*16 bits of mask ROM and a 29F040 flash ROM (to store the scanned text I assume). A few TTL parts, a DC-DC comverter, a compartor chip and an ERS232 buffer. Nothing really odd. Anyway, the problem is that the software is for an OS I don't have or wich to run. The manual doesn't give the seiral protocol (or even the baud rate), does anyone know of a description of it, or any open-source software that talks to this device? -tony

14 years, 1 month

Speaking of paper tape....

by IanK＠vulcan.com

Does anyone out there have some or all of the "Paper Tape System" tapes for the PDP-11/20? We have a couple of 11/20s with the basic 4kW installed, and I'd like to set up a machine to demonstrate the life of a paper-tape-based programmer. I'd be glad to cover your expenses for a copy or, if it's more convenient, pay shipping for you to loan them to us and we would make the copies. Or, if someone is aware of where images of these live that I haven't been able to uncover, I'd be grateful for a pointer. Please feel free to contact me privately. Thanks! -- Ian UNIX is user friendly. It's just selective about who its friends are. Ian S. King, Sr. Vintage Systems Engineer Living Computer Museum A project of Vulcan, Inc. http://www.livingcomputermuseum.org<http://www.livingcomputermuseum.com>

14 years, 1 month

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test-drb March 2010