test-drb October 2005

test-drb@ccmp.vtda.org

264 participants
655 discussions

by bqt＠Update.UU.SE

On Thu, 20 Oct 2005, djg at pdp8.net wrote: > For multi user operating systems the only one that will run on your > hardware is Multos-8. The version that has been recovered doesn't seem > to operate well though. Huh? As I believe all copies of Multos actually comes from a distrubution I have, this is news to me. Multos works just fine on my PDP8 atleast. However, it won't be much for the original question on this thread, as Multos don't support the RL8A either... Johnny Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt at update.uu.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol

20 years, 1 month

OT: Language for the ages

by cclist＠sydex.com

Here's an interesting problem. Suppose you wanted to write an application for a manufacturing process that will, in all probability, run for the next 30 years. No direct control of the process itself is entailed (i.e., you don't need the program to operation valves or run motors), but you do need this program to compute manufacturing parameters for each customer. I/O requirements are very modest, mostly simple keyboard and display. What would you write it in? Clearly, you'd want to be independent of a particular software vendor, so the likes of Visual BASIC isn't an option. You'd also want to write in a language that isn't nearing obsolesence, nor one that's still evolving. "Niche" languages would be out of the question, as longevity could be a problem. So what would it be? My vote is for FORTRAN. Cheers, Chuck

20 years, 1 month

Short review of $550 power cord plus a new SWTPC 6800

by ajp166＠bellatlantic.net

> >Subject: Short review of $550 power cord plus a new SWTPC 6800 > From: "Michael Holley" <swtpc6800 at comcast.net> > Date: Thu, 20 Oct 2005 19:18:38 -0700 > To: <cctalk at classiccmp.org> > >With all of this ragging on audio nut who spend obscene amounts of money on >wire, I decided to at a look. I don't know why we call them crazy, they >don't have 1975 computer running in the basement. > >The guy in the next office is in to high end audio. (Although he claims that >he is in the lower end of the people in his audio club.) I asked if he had >a power cord so I could take some pictures. He had a spare PS Audio xStream >Statement Power Cable, the 2 meter version lists for $550. This is 6 gauge >oxygen free copper with machined connectors. The cord has a ferrite >impregnated jacket. > >Here is my short review of the power cord >http://www.swtpc.com/mholley/MP_F/PS_Audio.htm If the sound doesnt improve is there a fee to decontaminate the plug of the outlet cruft? ;) >I took it home and hooked it up to my new custom case computer which also >cost me about $550. It is a modern 3 GHz Pentium that looks like a 1975 >SWTPC 6800. >http://www.swtpc.com/mholley/MP_F/MP_F.htm#NewCover Nice case. I need to work out a way to get the picture of my Altair-11 up. Whats an Altair-11 it's a old Altair 8800 case with a PDP-11/23 inside H780 PS, H9281AC 12 slot backplane and a RD52. Allison

20 years, 1 month

Fan for DEC H7861 power supply?

by ajp166＠bellatlantic.net

> >Subject: Fan for DEC H7861 power supply? > From: David Betz <dbetz at xlisper.mv.com> > Date: Thu, 20 Oct 2005 22:38:02 -0400 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >I've made a bit of progress with my new 11/73 (got a prompt from >console ODT), but I found a problem. One of the power supply fans is >dead. Anyone know where I can get a replacement fan for the H7861 >power supply? > >Thanks, >David Memory test is; they are Rotron or equivelent 120V AC fans. Measure one and look it up on the net. FYI they push a fair amount of air. so any 120V fan that uses the same ac current and fits is likely a good match. Allison

20 years, 1 month

PC floppy cable twists...

by ajp166＠bellatlantic.net

> >Subject: Re: PC floppy cable twists... > From: "Chuck Guzis" <cclist at sydex.com> > Date: Thu, 20 Oct 2005 17:54:49 -0700 > To: cctalk at classiccmp.org > >On 10/20/2005 at 8:41 PM Allison wrote: > >>Under those conditions I don't worry about my media unless its old >>and unknown. > >That's nice if you can make it happen, but I recall that our first >commercial installation of a 5.25"-equipped system was in a parking >garage... > >Cheers, >Chuck Well thats the challenge as an engineer. Good, Fast, Cheap, pick any two. Allison

20 years, 1 month

Weird BiPolar ROM programmer

by ajp166＠bellatlantic.net

> >Subject: Weird BiPolar ROM programmer > From: "Joe R." <rigdonj at cfl.rr.com> > Date: Thu, 20 Oct 2005 20:48:10 +0000 > To: cctalk at classiccmp.org > > I was out today and found an interesting looking box made by Aydin >Controls. It looks like a BiPolar PROM programmer. It has two 8 pin ZIP >sockets marked Read and two others marked Program along with several LED >diplays (TIL 311s! :-) and a lot of switches and pushbuttons on it. It >looks old so I decided to open it up and see what kind of microprocessor it >had in it. However I couldn't find one! It has four AMD 2101 RAMs, twelve >TIL 311 displays, a COM 2017 UART and a COM 5016 baud rate generator but >everything else looks like standard 74xx TTL. I couldn't find anything that >looked like ROM, PROM, EPROM or a CPU. Is it possible that this thing is >all controlled by TTL logic? Has anyone ever seen anything like this >before? FWIW most of the ICs are dated 1982 so I guess it that's when it >was made. > > Joe I used to blast bipolar proms using switches and some ttl so yes it could be a simple sequential logic thing. Allison

20 years, 1 month

PDP-8/A Front Panels

by v.slyngstad＠verizon.net

Charles Morris and I have been working to create an equivalent for the KC8A programmer's panel for the PDP-8/A. This panel uses modern parts where necessary, but follows the DEC design quite closely. The buttons and LED displays are larger, and it is designed to mount flush with the front of the PDP-8/A, where the original mounted to a beveled aluminum casting. Like the originals, there are two long, thin PCBs, held together with spacers, and affixed to a metal panel that attaches to the rack/8A. Charles has recently finished an awesome job of debugging the prototype (thanks, Charles!). (My job has been to drive the CAD tools and get the prototypes ordered and such.) Now he has the panel he needed to check out his 8/A :-). Now that we have (revised) CAD drawings and such for the front panel assembly, we are thinking about ordering boards for a "group buy", and want to see how much interest there is in these items. Unfortunately, the front panels are not inexpensive. It will cost us about $200 to place a PCB order(1), plus about $20 for each pair of boards (including the first one) ordered. Parts for each board pair run about $50. The metal panel is about $85 from Front Panel Express (which allows the panel to be mounted and look nice). In addition, there are costs associated with the prototype that we'd like people to help with, that are around $200. As you can see, the price is quite daunting for a single front panel: $220/1+$50+$85+200/3 = $422. Hence the attractiveness of a group buy. If we can order 5, then the cost each will be $220/5+$50+$85+$200/5 = $208. If we can order 10, then the cost each will be $220/10+$50+$85+$200/12 = $174. (That's under $100, if someone can make the metal panels :-).) I know there are many who don't have programmer's panels for their 8/A. So, are any of you willing to put up that kind of money to get one? Send me a mail with "I'd want one if the price gets to $xxx or less."(2). Thanks! Vince (1) We can't use an inexpensive prototype shop due to the boards' size: 15.5"x3.7". (2) I put up a lame page at http://so-much-stuff.com/pdp8/kc8a.html with some pictures of my prototype (not Charles' debugged one).

20 years, 1 month

PC floppy cable twists...

by ajp166＠bellatlantic.net

> >Subject: Re: PC floppy cable twists... > From: "Chuck Guzis" <cclist at sydex.com> > Date: Thu, 20 Oct 2005 17:05:50 -0700 > To: cctalk at classiccmp.org > >On 10/20/2005 at 7:42 PM Allison wrote: > >>Media wear, I've had disks spinning for years in clean environments and >>several dead drives that were still fine. > >Dirt happens. It gets between the head and the media and doesn't do any >favors to either. I've got several diskettes in my collection that have >the oxide coating worn clear through on the directory track. Better to >either stop the motor or lift the head. Around here, during the driest >months of the year (August and Sepember), the clay soils turn to a very >fine powder and become airborne. Hoiuse dust during those months tends to >have a brownish color. > >Add to this that most PC's have fans on the power supply that are set to >exhaust air from the box, which means that the drive slot is a convenient >entry point for contamination. It used to be that fans were set blow the >other way and filters were used. That is a PCism. That being those fans that suck unfilterd crud and cruft into the system. In the summer we do get brown dust from whatever. All of my systems cooling and air flow get attention even if it requires some card stock and tape duct work. Fans blow in and filters keep cat hair and other deutrius from getting in those places where it's going to do bad things. I find that tends to keep the inside of my PCs clean too. I turn the fan around and add a filter. Beats having a hairball clogging the cpu fan and crashing the system. Under those conditions I don't worry about my media unless its old and unknown. Allison

20 years, 1 month

PC floppy cable twists...

by ajp166＠bellatlantic.net

> >Subject: Re: PC floppy cable twists... > From: "Chuck Guzis" <cclist at sydex.com> > Date: Thu, 20 Oct 2005 16:02:43 -0700 > To: cctalk at classiccmp.org > >On 10/20/2005 at 6:23 PM Allison wrote: > > > >I think we're saying the same thing in different ways. If you don't have a >head load signal, the head remains in contact with the media the entire >time the media's in the drive. If the spindle is rotating, that leads to >head and media wear the entire time (althought he drive needs to spin a bit >to seat the media correctly when first inserted). If the motor's turned >off, no media wear, even though the head's still in contact. Nope not talking about media wear at all. I'm talking about the SA400/TM100 generation drives that used a brush type motor with belt drive that have a far shorter life than most of the halfheights that use a brushless direct drive pancake motor. The media wear is less an issue than the other problem with double sided drives. Clapping, those with head load solinoids (SA450 comes to mind) the head load/unload would not be gentle on the media. Thats why most later drives continiously load the head even when not spinning. >And yes, motors with brushes will fail with time. When I wrote my first >8085 diskette driver, I just turned the drive motors on at boot, having >come off an 8" floppy environment. I was admonished by a Micropolis >engineer that this was not a good idea and that the motor should be turned >on only when needed. So media was inserted into drives with the spindle at >a dead stop, leading to serious problems with seating the media. So drives >were modified to include a little spin-up when the drive door was being >closed. Not everyone did this gracefully, however, leading to wrinkled >areas around the media hub and so reinforcing rings were introduced. Actually testing showed that freqquent start/stops were harder on the motor to a certain point. It was the high current that would eventually wear the commutator. If you ran the motors the problem was they were not ball bearing and the bushing would wear and the brushes as well. >The interesting thing is the chicken-and-egg nature of this. Initially, >you didn't want to spin the media all of the time on a 5.25" drive because >the brushes in the DC motor would wear. So a motor control line was >incorporated. But then, if you could stop the media from spinning, you >didn't have to have a separate head-load mechanism to guard the meda and >the head against wear while not in use. there was a balancing act. Wearout for mechanical reasons and surge startup. The trick was keeping the drive running once accessed as it was likely you'd be back soon, if not time out. That lowered the start stop cycle wear and got you closes to the mechanical wearout limit. The later drives with direct drive motors and the like eliminated those concerns. Then powering down was power/heat savings. Media wear, I've had disks spinning for years in clean environments and several dead drives that were still fine. Allison

20 years, 1 month

RL01 drive select plug and power supply questions

by ajp166＠bellatlantic.net

> >Subject: Re: RL01 drive select plug and power supply questions > From: David Betz <dbetz at xlisper.mv.com> > Date: Thu, 20 Oct 2005 19:02:24 -0400 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >Mine is a KDJ11-A processor, RL01, RX50, RX02, MXV11-AC boot, 1.5mb >memory. I'm planning on running RT-11 and maybe Unix. I'd like to add >an RDxx drive. It looks like I'll have to find a different bootstrap >board to boot off of an RDxx though. Thats a strange config. Workable but strange. Allison

20 years, 1 month

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test-drb October 2005