test-drb December 2010

test-drb@ccmp.vtda.org

154 participants
208 discussions

by snhirsch＠gmail.com

I was given a ZIP file that unpacks to two directories under MacOSX: Diagnostic1 MacUser All files are in pre-OSX "forked" format. I copied both resulting subtrees to a netatalk server and tried to access them from a 68k mac. For some reason, the second of these is visible under MacOS 7.x (tried several values of 'x')! The MacUser directory is fine - both data and resource forks are as expected. However, no matter what I've tried 'Diagnostic1' simply does not show up in the finder. I'm sure it's something basic, but I'm not much of an ancient Mac guru. Any ideas? Steve --

13 years, 5 months

1970s TTL specs and prices

by thomas.gardner＠sbcglobal.net

For some Computer History Museum work I need information on 7400 series Flip Flops (S and Normal, DIPs) circa 1973 (anything 1970-75). Anyone have any maximum clock speed and OEM volume pricing information on parts such as 7473 thru 79 or 74106-116? I must be getting old because I remember the 7474 well but I thru out my Yellow books years ago :-) Thanks Tom

13 years, 5 months

TRS-80 Model II Haul in York PA

by classiccmp＠vintage-computer.com

I was contacted many months ago by folks in York PA about a large TRS-80 Model II collection they need to get rid of. This includes several CPUs, hard drives, software, manuals and so on. Someone was supposed to collect this but has failed to do so and now the gear is in jeopardy of being scrapped VERY soon. If you can save all or part of this haul please contact me ASAP so I can put you in touch with the owner. This stuff should have been gone by the beginning of last month so time is critical to save it. -- Erik Klein www.vintage-computer.com www.vintage-computer.com/vcforum - The Vintage Computer Forums marketplace.vintage-computer.com - The Vintage Computer and Gaming Marketplace

13 years, 5 months

SCSI to IDE/SD community project

by lynchaj＠yahoo.com

Hi! I made this offer at Vintage-Computer.com forums and got some response so am also making the same offer on CCTALK. The following link is the design I referring to: http://n8vem-sbc.pbworks.com/w/browse/#view=ViewFolder&param=SCSI2IDE I am trying to decide what to do with the SCSI to IDE/SD project. I think it would be a good and helpful thing to have but recognize it may be too specific or overcome by events. If you are interested in buying a prototype board please contact me at mailto:LYNCHAJ at YAHOO.COM?subject=SCSI2IDE If there are 5 people interested I can get a batch of five PCBs made for $150 or $30 each. If there are 10 I think I can get the prototype board cost reduced to around $20 each. Please note if you buy a prototype board you don't have to actually build and test it. You can buy a board and have it sent to a volunteer builder for build and test. If the SCSI2IDE project is to succeed we have to get past the prototype board phase and into the hands of builders for coding. Obviously with prototype boards there are no assurances and you can expect there will be problems. We have to find those and fix them before a manufactured PCB is even a possibility. Thanks and have a nice day! Andrew Lynch

13 years, 5 months

SCSI on the small and cheap

by jws＠jwsss.com

Does anyone have experience or notes on the absolute minimum hardware to do parallel narrow (and slow) SCSI. Back in the early days, we were doing non arbitrated buses, and they are now essentially unsupported, and there are some more bits related to Attention that possibly has to be responded to quickly to keep from upsetting initiator stacks. However I would think a small circuit external to a small processor such as a PIC or AVR would allow one to fool most initiators, and do a simple device with SCSI on one side, and either ethernet or USB on the other, or even an SD ram part. The reset signal has some real constraints about getting the drivers off the bus really quickly, and that is one signal that can't be handled in software unless you have really fast response. Also there are some state transitions related to Reset that I think might have some issues. You would of course need to latch that a reset occurred and when your slow device got around to polling it it could handle that. Also when the states are decoded would not be too hard to record and latch. I just wonder if this would be less than the simple target circuits out there and would be very difficult to implement. The messaging and selection added some logic I have not studied in a long time such that there were some transitions that could not be easily handled either. Jim

13 years, 5 months

HP 87 Keyboard parts (plungers)...

by clay＠ArcherServices.com

I recently acquired an HP 87 that I was able to repair, all except for a few sticking keys. From digging through the archives at this site and the HP-80 Series sites it seems the only way people have found to fix these is to cannibalize the plungers from other similar keyboards. Has anyone figured out a way to repair these cracked key plungers yet? I have tried a few things like gluing and wrapping and melting, etc, with little success. Does anyone know a source for these plungers? The HP part number 1535-4043 still comes up on HP parts site with no stock. Clay

13 years, 5 months

Drive Type International Memories, Inc. (IMI) 5012H

by billdeg＠degnanco.com

The IMI 5012H is I am told a clone of the Shugart ST-512, which is a type 1 drive, can anyone confirm this? I am, working to resurrect an IBM AT. Silly me I disconnected the battery and lost the configuration settings. I attempted to run setup, but when I declare the drive to be type 1 (or 2), the system returns a 1780 error code (drive seek error)...which makes me wonder if this is not really a drive type=1. Thanks Bill Degnan

13 years, 5 months

Excessive optimization (was Re: what was VMS/OpenVMS written in?)

by ethan.dicks＠gmail.com

On Wed, Dec 1, 2010 at 9:42 PM, Chuck Guzis <cclist at sydex.com> wrote: > The Microsoft issue, I recall was with dead code elimination. ?The C > expression > > ? ? ? ?while( C != 0); > > could normally be eliminated if C was 0... I have used the following in embedded code to tight-loop the CPU in certain circumstances, intentionally requiring a reset of the processor to escape... for (;;) ; I suppose a good optimizer would know that you really meant to do that and should produce something resembling the following $1: JMP $1 ...but I certainly wouldn't want that statement optimized out entirely. > The beauty of a good optimizer is that it allows one to write legible > code that still turns in good performance. Indeed. The horror of a bad optimizer (and I _have_ seen this) is that it introduces bugs that vanish when the optimizer is turned off. -ethan

13 years, 5 months

apple Lisa2. Any advice on non-working floppy drives?

by terry＠webweavers.co.nz

I should add that these readings were taken while the machine was waiting for me to insert a disk (according to the screen icon). Actually a disk was already inserted. I also looked for any change in voltage on any of the pins when I clicked the icon to activate the drive. There was no change in any of the readings. Terry ----- Original Message ----- From: "terry stewart" <terry at webweavers.co.nz> To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> Sent: Wednesday, December 08, 2010 6:48 AM Subject: Re: apple Lisa2. Any advice on non-working floppy drives? > Hi Tony and others. Progress and pin readings from the Lisa 2 project... > > I've cleaned a couple of the 400k Drives thouroughly just in case the > machine was struggling with the mechanisms. No change. The drives still > sit there on boot in stubborn silence, although the LEDs inside are lit. > No sound or attempt at disk ejection when there is a disk present. > > I did some measurements on the Lisa Lite board input connector, and here's > what I found. I used the circuit diagram at > http://www.freeinfosociety.com/electronics/schemview.php?id=1417 . The > signals in brackets represent the corresponding pins on the sony floppy > drive. A disk was in the drive at the time. > > PH0 (CA0) - 0.2v but rises to 3.5v momentarily when the machine is first > switched on > PH1 (CA1) - 0,2v normally but every 4-5 seconds this pulses to 3.5v > PH2 (CA2) - Same as PH1 > PH3 (LSTRB) - 0.2v > WRQ (WRTGATE) - 4.9v > HDS (SEL) - 4.3v but pulses to 0.2 v every 4-5 seconds > DEN (ENBL) - 0.2v > RDA (RD) - 4.9v but pulses to 0.2 v every 4-5 seconds > WRD (WRTDATA) - 0.2v > MT (goes to Lite Adaptor circuitry) - 0.11 Returns to drive pin as > PWR - 3.6v > All 12v and 5v power and ground pins read what they should. > SNS - 4.9v but pulses to 0.2 v every 4-5 seconds > > I''m still digesting what this all means using the Lisa hardware manual > here > http://lisa.sunder.net/LisaHardwareManual1983.pdf . There is a > comprehensive explanation of how the drive interface works in section 6 > but I'm still digesting this and trying to get my head around it. > Appreciate that I'm not a techie and a lot of this stuff is new to me. > > As I see it at the moment, the drive is certainly getting power, and > appears to be getting signals. Whether these signals are the right ones > are another question? > > Terry (Tez) > > > ----- Original Message ----- > From: "Tony Duell" <ard at p850ug1.demon.co.uk> > To: <cctalk at classiccmp.org> > Sent: Monday, December 06, 2010 10:09 AM > Subject: Re: apple Lisa2. Any advice on non-working floppy drives? > > >>> >>> Tony, thanks for doing that bit of research. > ..... > ..... >>> I have a manual with some schematics and tonight I'll check and see if >>> the >>> LisaLite board is there. >> >> As I said a Google search found it fairly easily. The Lisalite board >> looks quite simple (the schematic is just 1 sheet, and I recognisd all >> the chips on it). I didn't do much more than glance at the schematic, but >> it seemed to be a dairly simple PWM generator using TTL coutners and '85 >> comparators. I think the control vaule is bit-serially loaded into a >> shift register on the board. >> >>> >>> >Firstly, since you have no idea as to the health of any >>> > of the parts, you can't deduce anything from the fact that swapping >>> > them >>> > out makes no difference. >>> >>> Not entirely true, as the Lisa 2 startup checks carry right through >>> until it >>> asks for a disk for inserted. So I can assume most parts are working. >> >> Can you? I have no idea what these startup checks actually test, but I >> would have thouht it as possible for one of the I/O chips that links to >> the drive to havee failed but in a way that it still passes the tests. >> >>> Incidently, the docs I have suggests this routine also checks the >>> LisaLite >>> controllers so (according to the machine anyway) these are ok. It's >>> hard to >> >> I wonder how? I couldn't see any way for the machine ot check that the >> PWM signal (the only signal truely sourced by the Lisalite board) is >> present and corret. >> >>> believe that THREE drives all have the same fault though. All inputs >>> into >>> the drive are from the LisaLite board. Maybe the diagnostic checks are >>> not >> >> Not really. While the only external cable from the drive does, indeed, >> plug into the Lisalite board, the shcmeatics show the most of the signals >> are simply passed (with no buffering or anything) between the 'Twiggy' >> connector back to the Lisa I/O board and the Sony drive connector. I >> think it's likely that any problems iwth those signals are not caused by >> the Lisalite board (broekn PCB tracks are not common). >> >>> as thourough as they should be. >> >> We don;t (or at least I don;t know) what hte diagnostics actually check. >> There's also the issue that you're using a defective system to diagnose >> itseld, and while most diagnostics are written assuming that anythign >> that hasn't been checked could well be defective, some are not. I've seen >> diagnostics that basically assume that the machine is working correctly, >> and which don't help _at all_ if there is a fault. >> >> I really do think you need to start making some measurements on the drive >> connecotr and see just what is, and is not, correct there. >> >> -tony >> >

13 years, 5 months

ebay: TRS-80 Model 4 (NJ pickup) $0.01

by legalize＠xmission.com

Item # 260703951205 FYI -- "The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download <http://legalizeadulthood.wordpress.com/the-direct3d-graphics-pipeline/> Legalize Adulthood! <http://legalizeadulthood.wordpress.com>

13 years, 5 months

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test-drb December 2010