test-drb June 2006

test-drb@ccmp.vtda.org

220 participants
447 discussions

by chrism3667＠yahoo.com

sorry, but it always seems to be the person who responds to name calling with name calling who gets the reprimand. He simply could have said that IHHO it wasnt a good idea or whatever. No...it gets insinuated Im smoking banana peals and that I make silly suggestions. Im afraid I found it a little offensive. --- cctech-bounces at classiccmp.org <jwest at classiccmp.org> wrote: > Chris M wrote.... > > And regardless of what he uses/collects, there was a > > better answer again IIMMHHOO. I offered an opinion > > dopey-boy. Maybe you're the silly rube after all. > > Please be civil on the list. > > Jay __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

18 years, 6 months

by chrism3667＠yahoo.com

so if someone puts a readable image of 2 facing pages of text in front of you, will all that stuph you typed still mean that much? And desperate as in the device now being used by libraries to archive countless tomes, the link to which was posted here a couple of months ago? Desperate or not, I refuse to sit and flip a book over ~500 times. I have obtained very suitable results with a cheap Aiptek Pencam SD (1.2mp) - on the first try! And image enhancement is possible if the results are less then desireable --- cctech-bounces at classiccmp.org <frustum at pacbell.net> wrote: > Chris M wrote: > > now an even better idea then a scanner is a digital > > camera. 2 - 3 megapixels (even 1.2!) is sufficient for > > archiving text and graphics. It MUST have the ability > > where you can vary the focal length (able to move a > > fixed focus lense in and out in relation to the image > > sensor. And you thought I wasnt going to say that all > > wrong?). I would also deem ancillary storage (i.e > > cflash etc) a necessity. Cheaper to ship then a > > scanner. Flat bed scanners are unwieldy, especially > > when it comes to archiving bound stuph. > > What you propose is something to do if you are desperate, but not > something you'd want to do routinely. > > Taking a picture of an 8.5" x 11" sheet of paper with a 1.2 mpix camera > would get you 113 DPI. > > In reality, it is worse than that. 99% of all digital cameras lie about > their DPI -- a 1.2 mpix camera doesn't have 1.2 mpix red, 1.2m green, > 1.2m blue sensors. Different sensors have different patterns, but > essentially they count each r, g, or b subsample as a pixel and > interpolate. a common pattern is a tiling like this > > R G B G > G B G R > > Heavy duty image processing does its darnedest to hide this fact, but it > is obvious in certain circumstances. Take a picture of a B&W newspaper > from some distance where you will get some aliasing and then look at the > picture -- you'll get lots of color fringing. The only camera sensor > that doesn't do this is the one from foveon: > > http://www.foveon.com/ > > This is a nice tie in to classiccmp -- the CEO of Foveon is Federico > Faggin, co designer of the 8080 and co-founder of Zilog. > > Finally, the linearity of cameras is horrible for work like this, so the > effective DPI will drop even lower. > __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

18 years, 6 months

ComputerVision CADDstation 32

by compoobah＠valleyimplants.com

No takers on the CV yet- I'm a bit disappointed since this is (IMO) one of the more interesting machines in my stable. The fact that no one offered anything in trade isn't too surprising (I just didn't want to turn anyone down if they had a MVAX 3100 or a DEC AXP in their garage that they didn't know what to do with...) What is surprising is that no one expressed any interest at all Perhaps it was because I forgot to say where it was - Renton, Washington (Western side), ZIP 98058 Bribes still accepted, but not required (if that wasn't clear from the first posting). Scott Quinn

18 years, 6 months

Mis-categorized and not cheap...

by wh.sudbrink＠verizon.net

but in case someone wants a SOL-20 really bad... ebay item: 8825526106 Starting bid is at the top of the value range (IMO) so I don't thing anybody is going to snipe it.

18 years, 6 months

New version of PDP-10 & -11 OS to Layered Product XRef

by healyzh＠aracnet.com

After 3 years, I've been able to update the PDP-10 and PDP-11 OS to Layered Products Cross-reference. I ran across a pile of RSTS/E and Micro/RSTS SPD's yesterday. As a result there is now info on Micro/RSTS V2.0 and V2.1, and RSTS/E V9.2-9.6. http://www.aracnet.com/~healyzh/PDP-10_11_OS_xref(V2b).pdf As always, if anyone can provide information to help update this, I'd appreciate it. Zane -- | Zane H. Healy | UNIX Systems Administrator | | healyzh at aracnet.com (primary) | OpenVMS Enthusiast | | MONK::HEALYZH (DECnet) | Classic Computer Collector | +----------------------------------+----------------------------+ | Empire of the Petal Throne and Traveller Role Playing, | | PDP-10 Emulation and Zane's Computer Museum. | | http://www.aracnet.com/~healyzh/ |

18 years, 6 months

DECnet network at VCF Midwest 2.0?

by aijones2＠bsu.edu

>Hey, is anyone here interested in getting an ethernet DECnet network >together at VCFMW? > >I'll be bringing my PDP11 which has DECnet/E on it :) I recently obtained SGI 4DDN 4.1, so I'm seriously considering bringing a DECnet-capable Indy if I can work out the licensing bullshit...

18 years, 6 months

New Altair32 "hardware"

by dm561＠torfree.net

On Behalf Of Ethan Dicks On 6/9/06, Cini, Richard <Richard.Cini at wachovia.com> wrote: > All: > > I want to add a real time clock to the Altair32 but I want > to throw this out there for comment. Would one rather use a "faceless" > RTC (like the Compu/Time) or one with an on-screen display like the > Hayes Chronograph? The Compu/Time is very easy (nearly done coding) but > the Chronograph would be prettier. Personally? The Chronograph. I have a real one, so, of course, I'm biased. I've often contemplated making a Chronograph emulator, but it would take a graphical LCD; a 20x4 Text LCD can't quite do it justice (because of the day-of-the-week at the top of a real Chronograph's VFD). -ethan ----------------- Reply: Some older VCRs had a similar display, with the weekdays across the top; shouldn't be too hard to find one at the curb. mike

18 years, 6 months

Repair methods (was Cromemco 3101/Beehive B150 score)

by roger.holmes＠microspot.co.uk

>> >> With a modern machine with just three or four modules (say power >> supply, >> logic board and one RAM module) then you take an informed guess >> and can >> swap modules until you guess right, unless of course a module you did >> not >> swap causes failure of another module. Then it gets expensive. > > That is _exactly_ what I object to. Fault finding is not (or rather > should not) be bbased on guesswork. Unless you've found the fault > logically, you can't know you've fixed it. For modern machines, that is the way the manufacturer wants it done, when doing warranty work, they will not pay for true diagnostic work. My company is not even required to have an oscilloscope, though we were until recently required to have an implosion booth with a mirror for when calibrating a CRT monitor or changing a CRT. Now all the CRT monitors are out of warranty and they only sell LCD displays we have taken it apart. > I've got stories of where a problem in one module appeared to be > cured by > replacing a different one that was, say, more tolerant of timing > errors > on one of the signals. Of course the problem came back as the timing > error (which was the original fault) got worse. Yes, and of course maybe the temperature had changed slightly or the voltage had drifted. Four of the power rails in the 1301 are fitted with marginal check facilities, it is possible to switch them off of the standard power stabilisers and wind them up and down via knobs on the machine's front panel. There is also a facility for varying the clock rate up and down. In service, engineers were issued with special hammers to hit the printed circuit boards with to check that vibration did not cause a failure. In all there are about 100 power supplies in the machine, and nearly all have potentiometers hidden away under the covers which adjust the voltages. > > And this is one reason I don't have a modern computer. I don't have > (and > can't afford) the necessary test gear to be able to _prove_ which > module > is at fault. > >> I have scrapped an almost complete machine, so I have many of the >> commonest >> modules. I understand digital electronics but I find it hard to get >> my head around >> the analogue electronics on the boards. Testing bare components is > > 'Digital circuits are built from Analogue parts' (one of Vonada's > lawas > IIRC). > > I haev never understood how you can understand digitial electronics > properly and not understand analogue electronics. I certaimly couldn't > understnad digital stuff until I understood things like transmision > lines, termination, etc. There is a big difference between fault finding digital electronics and designing digital electronics. Where there is an analogue signal, like in the Drum Write amplifiers I can cope with that, but there is some weird stuff, like there is a piece of what looks like 4 inches of coaxial cable - which is apparently a delay line and the signal bounces off the far end and comes back a bit later. There are 250 of these in the core store, they never go wrong, but the boards they are on tend to burn out one of their resistors frequently, and the core store itself is a current device, so fault finding with voltage based instruments can be tricky. What I find difficult in an analogue circuit is finding the order of what drives what. Sometimes its easy, but often the circuit diagrams are drawn in an illogical order, and sometimes there really is deliberate feed back, the flip flop is an obvious example. One time one of the three phase transformers was frying, it was in a very awkward place. I pulled the output fuses and it continued to fry. Eventually I changed it and the new one did the same, it was the three phase bridge rectifier (six big diodes) which was shorting out, I had not realised it came before the three fuses (feeding three circuits) rather being on the three secondaries of the transformer. Yes I should have checked the circuit diagram, but that meant searching through several hundred circuit diagrams, and I thought I knew what was doing. Wrong! Anyway, no harm done. > > >> hard enough >> but testing them in circuit is tricky, especially if they require >> half a dozen different >> supply rails at weird voltages such as -18.0 -17.1, -12.6, -6.3, >> -4.6, -2 and +12.6. > > I think if I had a machine like that to maintain, I'd make up a > test rig, > with a power supply giving those voltages. I have thought about it, its one of those things I will do when I get a round tuit. > > >> >> 1960s components which look right are not easy to get new. The > > To be honest, I don't care too much about the appearance of the > components, provided they are electrically correct. There are > certainly a > few obvious modern replacements in my 1968 HP9100B. But I am hoping a museum will take it sometime as a working exhibit, it is the last working one if its kind, and at one time its type was about 25% of the computers in Britain. Its biggest selling point was pounds shillings and pence in hardware. Then the IBM 360 came along and wiped the floor with all the other computer makers. What museums hate to see is modern components, so where there is a choice I stay with original parts, and always keep the original faulty parts when I have to use modern - such as when I put an old Apple switch mode power supply in place of an old supply which used a transformer which is no longer available. Actually there were several identical power supplies in that Paper Tape Reader, and they all plugged into a big connector which had links to configure the power supply for the required voltage needed in that position. I put the duff one in a position where the required voltage was nearest to the Apple's voltage (I think it was -17.1 volts, so I used the -12 and +5 volt rails and kept the other voltages, including ground and the case insulated). Roger.

18 years, 6 months

stuff I got dumped to me today :)

by Watzman＠neo.rr.com

Re: "1) A mint condition Heathkit H27 (dual 8" floppy drive for H11). Wonder if it's usable on anything else?" Yes, it is. The box has two absolutely garden variety standard Memorex 550 8-inch floppy disk drives in it (SSSD). They have an absolutely standard 50-pin Shugart SA-801 compatible interface. They are currently connected to a controller located in the bottom compartment of the drive case, below the drives (I think it's a single board computer with a Z-80 and a 1771 on it, but my memory isn't that good). Anyway, disconnect the cables going to the built-in controller, and connect your own 50-pin ribbon cable, and you can use the drives, cabinet and power supply with almost any system that takes "standard" (e.g. Shugart compatible) single sided 8" drives.

18 years, 6 months

by chrism3667＠yahoo.com

now an even better idea then a scanner is a digital camera. 2 - 3 megapixels (even 1.2!) is sufficient for archiving text and graphics. It MUST have the ability where you can vary the focal length (able to move a fixed focus lense in and out in relation to the image sensor. And you thought I wasnt going to say that all wrong?). I would also deem ancillary storage (i.e cflash etc) a necessity. Cheaper to ship then a scanner. Flat bed scanners are unwieldy, especially when it comes to archiving bound stuph. __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

18 years, 6 months

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test-drb June 2006