test-drb July 2000

test-drb@ccmp.vtda.org

155 participants
521 discussions

by Anthony.Eros＠compaq.com

I'll definitely be looking at alternatives in the future. The other shoe in this is that it appears the shipper didn't bother to insure the package, despite my instructions to the contrary. Of course, those instructions were over the phone, not via e-mail, so I'm getting the "you didn't tell me you wanted me to insure it". Gee, now why wouldn't I want it insured? :-( -- Tony > ---------- > From: Bruce Lane[SMTP:kyrrin@bluefeathertech.com] > Reply To: classiccmp(a)classiccmp.org > Sent: Thursday, July 27, 2000 10:02 AM > To: classiccmp(a)classiccmp.org > Subject: An alternative to UPS > > At 08:25 27-07-2000 -0500, Joe Rigdon wrote: > > >>If it's used (like an old computer) it's "personal > >>effects" and as such any damage or loss claims will be denied. > > > > That's the most rediculous thing that I've ever heard! I hope they > find > >your computer lab. If not, then don't give up. Demand to talk to their > > <snip> > > Absolutely don't give up! UPS is easily the most snooty company I've > ever > dealt with on insurance claims. A colleague of mine back east had to > hassle > them for months before they finally paid up on a claim. > > Also, you may want to look at an alternative. I don't know if they > do > ground to Canada yet, but I've had outstanding service from FedEx Ground > (formerly RPS). Nothing I've shipped so far has been lost, or damaged in > the slightest degree, and their customer service is excellent. > > Perhaps the capper is that I've found they're actually less > expensive than > UPS. I've had a shipper account with them for months now. If I drop all my > outgoing at their depot, they don't even charge me a monthly fee. > > > -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- > Bruce Lane, Owner and head honcho, Blue Feather Technologies > http://www.bluefeathertech.com // E-mail: kyrrin(a)bluefeathertech.com > Amateur Radio: WD6EOS since Dec. '77 > "Our science can only describe an object, event, or living thing in our > own human terms. It cannot, in any way, define any of them..." >

23 years, 7 months

New Finds Today

by jrkeys＠concentric.net

Had a good day today as I got a digital TK25 with cable and a Sharp PC-500 portable computer with a built-in printer for 10 bucks total. The PC-5000 has a very small but long liquid crystal display of 640x80 dots and is one weird laptop computer. No power supply was with it and the battery seems to be dead. Anyone know anything about it. Also picked up a neat 3 foot robot for $1 here at a thrift store. No remote was with it a and one cover plate is missing, have not tried to power it up yet. Keep computing John Keys

23 years, 8 months

Tim's own version of the Catweasel/Compaticard/whatever

by allisonp＠world.std.com

From: Richard Erlacher <richard(a)idcomm.com> To: classiccmp(a)classiccmp.org <classiccmp(a)classiccmp.org> Date: Wednesday, July 05, 2000 7:30 PM Subject: Re: Tim's own version of the Catweasel/Compaticard/whatever >You may be onto something, Tim, but I'd make one observation here. The >signal on pin2 of the 8" drive cable, though often driven with the >1793's TG43 signal, does not turn write precomp on and off, but, rather, >reduces the write current to the heads. This reduces the amplitude of the >signal In many cases it's also used to alter write precomp. Most all have some precomp (Esp DD controllers) and for the TG43 case they alter the precomp to further compensate for bit shift due to the close magnetic domains. >driving the heads, hence reduces the overall amplitude of the recovered >signal as well. That same signal is used to enable write precompensation on Bogus. the levels are dealt with in the read amps with margin as well. What's changing of the write current really impacts is the read bit shift (aka peak shift) as the bit density goes up (inner tracks are shorter than outer). >some controllers, many of which use a less-than-ideal timebase to define >the precompensation offsets imposed on the data stream. This is true, or worse used oneshots. generally the time base for the bit encoding was always a crystal with not worse than 200ppm error and less than 50ppm drift. The typical system was usually within 50ppm of exact and drifted less than 25ppm over temperature extremes. Often the actual data rate was far lower than that reference(usually 1/4 or 1/8th). >Do you think you could take a stab at swapping the timebase on your >Catweasel board with a 32 MHz crystal? I think that would be VERY >illuminating, particularly where these precomp/write-current-related >effects >are concerned, because phase noise introduced by the deviation of the >Catweasel timebase from a harmonic of the data rate adds confusion. There lies a connundrum, study the media and the magnetic domains therein or get the data? A lower clock would be adaquate for getting the data. Further, while I was studying digital PLL state machines I found a point where increasing the clock (greater resolution) produced sharply reduced improvement. Signal processing theory (analog) suggests the same. From: Tim Mann <mann(a)pa.dec.com>: >> So, what's the heuristic? It's quite crude and oversimplified too, >> seems to work pretty well. The general idea is that if an interval is >> a bit off from what you were expecting it to be, multiply the error by >> some factor around 0.5 to 0.8 (you sometimes have to tune it for each >> disk if they are particularly bad), and add that to the next interval I'd suggest some factor less than .5, flux shift errors on floppies rarely move a great amount unless the spindle bearings are rattling loose. Actually based on media and expected recording rate it's possible to plug in a set of expected timing windows and add/subtract a "precompenstation" window amount based on adjacent bits. For example adjacent ones or zeros (especially more than two bits) tend to spread or compress over patterns like alternating ones and zeros. Further with all the "timing image" in a memory it should be possible to look at longer strings of transistions and do simple predictive forcasting (software PLL). Add to that the encoding form (FM, MFM, M2FM, RLL or GCR), and previous bits history it should be straightforward enough to predict the likely next transistion(s) be they one or zero. It is serediptious that the code you have effectively accomplishes a tracking filter (type of PLL). Why, many of the parameters on the media like peakshift and other behavours tend to average themselves and cancle. Most of this stuff is not rocket science, it does however require seeing into the set of abstractions to make them obvious. Allison

23 years, 8 months

Kewl new find

by foo＠siconic.com

I came across a deliciously mysterious computer today in a local thrift store. I took the following photos of it in various states of undress: http://www.siconic.com/crap/BMC-1.jpg http://www.siconic.com/crap/BMC-2.jpg http://www.siconic.com/crap/BMC-3.jpg http://www.siconic.com/crap/BMC-4.jpg http://www.siconic.com/crap/BMC-5.jpg http://www.siconic.com/crap/BMC-6.jpg It's a machine made by OKI of Japan (the same company apparently that made the Okidata printer line). It's called the Small Computer Model 10 (as indicated by the photo of the nameplate). At first I thought it was just some dumb terminal until I started looking closer at it and discovered it was indeed a computer. Upon examining the innards I found that it has a Z80 processor and seems to be circa 1982. I couldn't tell how much RAM it had because the chips are all funky Japanese types. My guess would be 32K-64K. As one can see from the photos, it incorporates a dot matrix printer in the main unit. If you've got one to compare to, the machine is almost exactly the same dimensions as a Sol-20 (and just as heavy). It has an expansion bus inside, and two cards are plugged in: a floppy drive controller (marked 5-FDD) and some sort of CRT interface (marked C-CRT, probably color CRT). The right-hand side has three DIN connectors, labelled L-PEN (lightpen), TV (probably an RF connector), A-CMT (?). Finally, there is a DB-25 RS-232C connector. The left-hand side features the power switch and two momentary buttons, one marked IPL and the other NMI. I was hoping when I plugged the machine in I would get output to the printer but no go. I tried blindly typing some BASIC commands like LPRINT but that had no effect. When it first turns on, there is a 3 second beep that comes out of the speaker. If I hit the IPL button it seems to reset the machine: there's a moment of about 3 seconds after pushing the button where nothing happens but then the speaker beeps for about 3 seconds again. I tried pressing various keys (like HARD COPY) but could not get any action out of the printer. I imagine it wants to be connected to a CRT. I didn't know at the time to look for a CRT so I'll probably go back tomorrow to check around. I'm also going to check for any floppy drives that might go with it. I'd like to try to hook it up to a TV but I don't know what pins I should use. I have a working scope but it's huge, old and is at my warehouse. What would be a good way to try to determine which pins carry the signal? Any help or info would be appreciated. Sellam International Man of Intrigue and Danger ------------------------------------------------------------------------------ Looking for a six in a pile of nines... VCF 4.0 is September 30-October 1 San Jose Convention Center, San Jose, California See http://www.vintage.org for details!

23 years, 8 months

PDP-11/34 & RK05 Questions

by pdp-11＠swbell.net

I am getting my PDP-11/34 and my RK05 disk drives and packs tommorrow, and I have a few questions.They have have been in storage for years, and, although they have been kept dry, they are probably dusty. Can anyone tell me how to clean the drives and the disk packs before I use them? Thanks, Owen

23 years, 8 months

Another reason to preserve systems

by rdd＠smart.net

Greetings, A short while ago, I just thought of yet another reason to preserve computer equipment, particularly that which is the most durable. While doing some research for someone else pertaining to application service providers (ASPs) - which I don't like, I began thinking of things mentioned by Sun and Microsoft that give me the creeps: the thought of programs, applications, operating systems and, worse yet, one's own data, aacessed by, and stored somewhere on, the Internet, not locally. A user would have no control over one's files. If enough people will be foolhardy enough to fall for the marketing hype, and begin using "network appliances" instead of computers, 10, 20, or 30 years from now, will home computers with local mass storage even be sold, or be legal to own, for that matter? After all, we know what mindless sheep most people appear to be when it comes to following the herd and not thinking for themselves. BTW, what I've been researching is the danger of the use of ASPs for medical claims processing, and when one begins digging into this, one begins to see the commercial and governmental interests involved in people's medical records, and it's not nice. There's the problem with non-objective medical information presented by web sites such as WebMD/Healtheon (which also want to process medical claims as ASPs) due to conflicts of interest who have advertisers and shareholders to consider. For those in the US, some may be surprised when they learn the realities of HCFA and the HIPAA, and how much privacy they stand to lose by laws promoted by certain politicians (including the president) as increasing privacy, when they really do just the opposite - not to mention the temporary moratorium on national IDs for everyone to be used for medical purposes, ...then there's the work towards the creation of a national database for medical records. I won't even begin to touch on such areas as the commercial and governmental influences involved with the A.M.A. (no wonder many physicians don't belong to it!) and conflicts of interests that affect nonpprofit web sites such as Intellihealth (look into its connections with Aetna, and what Aetna has done to people's health with it's HMOs) and Medem. Before anyone flames me, please look into this yourself if you value your health and the confidentiality of your medical records... then express your concerns to your physician. -- R. D. Davis rdd(a)perqlogic.com http://www.perqlogic.com/rdd 410-744-4900

23 years, 8 months

SCSI settings HP 7980 S tapedrive

by fmc＠reanimators.org

wanderer <wanderer(a)bos.nl> wrote: > Does anyone know how to change the SCSI id settings on a HP 9 track > tapedrive model 7980 S? It's current setting is 3 but that is > conflicting with my disk. There is no thumbwheel and there are > no visible jumpers to find. It's on the front panel. You press: You see: OPTION TEST * NEXT CONF * NEXT INFO * NEXT ID * ENTER ID (blinking #) Hmm, I would think you could press PREV and NEXT to cycle through at this point, and ENTER to set the ID, but the drive I'm fiddling with (actually a Tandem 5160) doesn't want to let me use PREV or NEXT here -- I bet I have to play with a CONF option to unlock the SCSI ID. And I don't have the manual handy right now. -Frank McConnell

23 years, 8 months

Switch-Mode PSU Failure Modes, Repairs, & Parts Substitutions

by dhquebbeman＠theestopinalgroup.com

Good Morning, I hope everyone had a great weekend, I sure did (not Classic-Computer related so I won't bore anyone with the details)... Subsequent to my first post about my Prime PSU, Don Maslin sent me a howto on repairing switchers, that was written by Keith Lofstrom. The howto is fairly comprehensive, but does assume that most repairs are taking place due to bad PSU design. I'm not sure mine failed due to bad design. It was dusty, and after I removed it, I found that the 2455 cabinet has an interestingly-design set of airflow guides that's above the cage; it's basically a sheet of thick plastic with holes in it, so that the dual-squirrel-cage blower dumps air into the cage through these holes. While there was some airflow, once the PSU was out, I could see that many of the holes were clogged up with dust and lint, and thus I think the PSU simply overheated inside the cage. One additional data point that I thought I'd mentioned, but may not have, is that: The system was up and running fine, no evidence of any problems. I shut the system down that night, and then the next day when I turned it on, I got nothing. I did not see any evidence that the PSU briefly came on and then died; it simply never came on. >From what I've gathered from the comments posted about switcher operation, and from Keith's howto, it seems like something failed that is part of getting the secondary supplies "jump-started" to an up-and-running state. So, as long as it was powered up, it would continue to operate. But once I turned it off, the portion of the PSU (something between the primary and secondary supplies? Something like that big power resistor, maybe?) that gets the secondaries going, couldn't get them going. So, has anyone else been in a similar position? Do I have a fair chance of simply replacing the parts I've found that failed, reinstalling it, and being successful? There is a 5v adjustment that needs to be made before bringing the system up all the way, and while I hate to use the system itself as a dummy load, I don't have the Prime bus pinout, so I can't easily determine what's what. One of the things Keith discusses in the howto is about parts substitutions. Most of his comments are w/r/t transistors and the like, and he suggests using as replacements devices that have voltage and current capacities that are increased over the part that failed. He goes on to say you need to test each such substition with a curve tracer before finalizing each such substition. However, I don't think any semiconductors failed for me. He says that in a good design, there are some power resistors protecting the switcher transistors, and from my examination to date, it appears that Prime did in fact put these in the design. I'm going to remove the other 3 of the 4 that are in that area to be sure whether any did or did not go open-circuit, as there is significant thermal discoloration of the underside of the PCB in that area. How reasonable a course of action is this? What's likely to happen should a problem still be present? I'm thinking that worst case, the parts that failed will just quickly fail again, putting me back at square one. As always, thanks in advance for any help y'all can give me! regards, -doug quebbeman

23 years, 8 months

4004 manual needed (fwd)

by vcf＠siconic.com

Can anyone help this guy out? Apparently, he's from Brazil. It's cool to see folks down in South America getting into the Classic Computer thing. Reply-to: gandalf.the.wizard(a)zipmail.com.br ---------- Forwarded message ---------- Date: Sun, 30 Jul 2000 16:13:15 -0300 From: gandalf.the.wizard(a)zipmail.com.br To: vcf(a)vintage.org Subject: Old Manual Greetings!! Congratulations for your home page! It is really the best resource I've seen about old computers. I am looking for a electronic version (.pdf, .doc, etc.) of the manual of the MCS-4 kit. As I know it was based on Intel 4004 microprocessor, used the 4001 ROM and 4002 RAM. I found some scanned pages of data sheets of these chips at http://www.piercefuller.com/collect/i4004/, but could not find the manual of the entire kit. I also find some parts of the manual, but they were not complete. Some chapters and tables were missing. (http://digiweb.com/~hansp/ccc/machines/mcs-4/index.htm). I also searched Intel's site, but found nothing. I will apreciate any help you can give. Thank you. Best regards, Ricardo Mecelis ________________________________________ Promocao Dia dos Pais PDA daVinci - Assistente pessoal digital onde seu pai podera utilizar para diversas ocasioes por apenas R$399,00 na MicroSite. Compre agora. http://www.microsite.com.br/produto.phtml?id=2443?&prop=1905 Sellam International Man of Intrigue and Danger ------------------------------------------------------------------------------- Looking for a six in a pile of nines... VCF 4.0 is September 30-October 1 San Jose Convention Center, San Jose, California See http://www.vintage.org for details!

23 years, 8 months

Whatever happened to the Flat-Pack (was Re: Discontinued IC's)

by CLASSICCMP＠trailing-edge.com

> There's also the weird secondary market that exists because of military > programs. TI has previously sold the IP and remaining dies for end-of-life > parts to other firms who then either continue production or package the > dies to meet military needs -- which is great if you need something in > a flat-pac... Whatever happened to the flat-pac? It seems to me to be a package that has many of the same advantages of modern SOIC's, but maybe 30 years ahead of its time. Was it a manufacturability issue? Was it a "proprietary" issue? The flat-pacs I worked with were ceramic or ceramic/gold, but it seemed pretty straightforward to me to do the same thing with plastic. Am I wrong? Besides, many of the flat-pac pinouts were different than the DIP pinouts, and this was actually a good thing in the case of many TTL IC's which had power and ground pins in weird places... It seems to me that in most cases SOIC IC's follow the DIP pinout (though I'm sure there are exceptions.) Tim.

23 years, 8 months

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test-drb July 2000