test-drb

test-drb@ccmp.vtda.org

101090 discussions

by lynchaj＠yahoo.com

Hi, I still have this IBM 5251 keyboard. Does anyone want it? It is just taking up space in my basement now. I have not made any modifications to it but I do not know whether it works or not. Since I have fixed a different parallel ASCII keyboard to work with my Vector Graphic restoration I no longer need this IBM 5251 keyboard. I would like to trade the IBM keyboard for a case to put my parallel ASCII keyboard in but other items gladly considered. Thanks! Andrew Lynch Vector Graphic Mail List: http://h-net.msu.edu/cgi-bin/wa?A0=VECTOR-GRAPHIC NorthStar Mail List: http://tech.groups.yahoo.com/group/NorthStar_Computers

18 years, 5 months

Programming skills (was: Teaching kids about computers...)

by dm561＠torfree.net

Date: Sat, 24 Nov 2007 23:54:44 +0000 (GMT) From: ard at p850ug1.demon.co.uk (Tony Duell) Subject: Re: Teaching kids about computers... >> Tools are developed to make a job easier and do it better; in my opinion taking >> advantage of those tools and doing things "the easy way" makes you more >> professional, not less. >I would agree, but... >1) Being able ot use the tools, however proficiently, does not >necessarily equate with being able to design/make those tools. -------- Why do my recent posts seem to generate such odd responses... Or is it just me? Why the "but"? Did I imply anything of the sort? Did I say that a carpenter should know how to make an electric saw or even repair it when it would be a more efficient use of his time and skills to just take it to a shop or buy a new one? ------ >I haev never used dBase (or any other database for that matter), so I can't >comment on that, but I will claim that being able to use _some_ >application programs does not make you a programmer. -------- A claim that seems pretty obvious; why make it? Although some people apparently disagree, dBase is not an application program; it's very similar to BASIC (and grew and matured just like BASIC did) but with fairly extensive file-handling and screen-handling capabilities. -------- >2) The initial question was about education. Education is not production. -------- Of course not! That may have been the initial question but by the time of my reply it had moved to opinions about what defines a "programming professional," specifically whether someone who codes in dBase or doesn't know or care about how disk drives work can call him/herself one. -------- >When you're prodcuing something, of course you use all the applicable >tools. When you're leaning about things, you have to do things 'by hand' >to understand them (and example of this, from another context, is that >photography couses used to insist that the students used cameras with >manaul focuessing and exposure cotnrol, so they could learn what said >adjustments meant, even though if you were being paid to take photographs >you would _probably_ welcome some automation). >In fact I will go further and say that the true professionals not only use the right >tools, but also fully understnad how those tools work and behave, because that >way they can use them more effectvely. ----------- I kind of thought that being "proficient," i.e. "having an advanced degree of competence" in their use of tools expressed the same sentiment. Of course as a professional you should know what those camera adjustments mean and do, but you don't necessarily have to know *how* they work unless you're interested or plan to go into camera design or repair, or expect to have to repair it in the middle of nowhere; "how they behave" is not at all the same as "how they work." And although you may know all the arcane details of your camera and probably look down on someone who only points-and-shoots, he or she may well take better pictures than you, which is after all the whole point of having a camera (for most people anyway ;-) ----- >> A programming professional's job is to deliver a product that meets the client's >> needs, is well documented and easily maintained, and is delivered on time and >> within budget. Knowing or caring about the arcane details of a disk drive or being >> able to program an OS-less computer in binary may matter if you're working on >> an embedded controller but it's pretty irrelevant if the project is a client accounting >> system for a large financial institution. ---------- >Tuew, but a 'client system for a large finanicail instution' is hardly >the only type ofr computer application. --------- Again, I thought that was obvious and that my mentioning embedded controllers would suggest that even I knew that and don't need you to point it out... My point was that there's more to being a programming professional than being able to code in binary; furthermore, different tasks require different tools and skills and different people have different interests and abilities, and I find the tendency for some people here to denigrate others with different goals, interests, abilities and tastes annoying enough on occasion to comment. m

18 years, 5 months

Babbage Calculating Machine Article 1833

by ed＠ed-thelen.org

> From: "B. Degnan" <billdeg at degnanco.com> > Subject: Babbage Calculating Machine Article 1833 > To: cctalk at classiccmp.org > Message-ID: <5.1.0.14.0.20071125093356.03328d50 at mail.degnanco.net> > > New York Weekly Messenger 2-13-1833 > Babbage Calculating Machine Article 1833 > On the back page of this newspaper is an article that describes in some > detail the eye-witness account of a *working* machine: "...the greater part > of the calculating machine is already constructed....I have had the > advantage of seeing it actually calculate, and of studying its construction > with Mr. Babbage himself..." The machine was never completed - long story > Does this account describe a working computer? No - to see more than you ever wanted to know about Babbage Difference Engine #2 see http://www.ed-thelen.org/bab/bab-intro.html > To help make this > determination I would want to learn more about the error checking > capability of this machine, which I assume was used for calculation of > significant digits. Error prevention was the name of the game. Bars and detents prevented motion at wrong times. The machine would jam rather than make a mistake. > A[s] described, Babbage's calculating machine could be > described as "computer-like" at least. I believe that this article reports > the closest Babbage got to a actual working computer. Or just an elaborate > calculator. There are no references in the article to what we today would > identify as punch cards or programming. Fixed program "Calculator" seems a good word. It was basically a seventh order polynomial evaluator. > Download the PDF > http://www.vintagecomputer.net/babbage/charles_babbage_2-13-1833.pdf > ...and read for yourself. The article describes error checking and how > results are viewed and how log tables could be calculated accurately, for > use in astronomy. The article noted that regarding the printer "..less > progress was made...". The second incarnation of the Babbage Difference Engine #2 (the 1st is in the London Science Museum) is now due in spring 2008 on loan to Computer History Museum, Mountain View, CA courtesy of Nathan Myhrvold. Doron Swade is currently Guest Curator :-)) http://www.computerhistory.org/about/staff/swade/

18 years, 5 months

available Fw: old DEC mini computer

by jwest＠classiccmp.org

Contact original emailer if interested.... Whoever gets this deal owes me... what with the two RK05's and all! Jay West ----- Original Message ----- From: "John Lundberg" <jlundberg at netins.net> To: <jwest at classiccmp.org> Sent: Sunday, November 25, 2007 12:43 PM Subject: old DEC mini computer Hi I have a DEC 310 system that needs a new home. This is a desk system with four 8 inch floppy drives. I also have 2 RK05 rack mounted drives and a wide carriage DEC printer. The system has not been powered up in many years but everything worked the last time it was on. Would you know of anyone who would be interested in acquiring this equipment? Thanks for your time, John Lundberg

18 years, 5 months

available Fw: micro pdp

by jwest＠classiccmp.org

Contact original emailer below if interested.... Jay West ----- Original Message ----- From: "Young, Steve W" <steve.w.young at lmco.com> To: <jwest at classiccmp.org> Sent: Wednesday, November 14, 2007 1:50 PM Subject: micro pdp >I have a micro PDP 11C23-RE with 1.5 Meg memory, tape drive and floppy, > RD52A, Ethernet card, 4 line card. Anyone want to buy it? Also vt240 > terminal. I am in San Jose. thanks > >

18 years, 5 months

Available DEC

by jwest＠classiccmp.org

I have not researched this further than what you see below. Contact original emailer directly... Jay West ----- Original Message ----- From: "cindy stewart" <patience1554 at yahoo.com> To: <jwest at classiccmp.org> Sent: Monday, November 12, 2007 10:01 PM Subject: We have what you want > Dear Sir: > We have a complete DEC PDP 11 system. If you are interested in > purchasing it, please write back to this address. > > Best Regards, > > Cindy Stewart > St. Augustine, FL

18 years, 5 months

DEC gear available in the UK

by jwest＠classiccmp.org

Here's one for our UK friends... Contact original emailer directly... Jay ----- Original Message ----- From: "Mike Moorhead" <mmxseawaves at enterprise.net> To: <jwest at classiccmp.org> Cc: <mmxseawaves at enterprise.net> Sent: Monday, November 12, 2007 7:09 PM >I have documentation and tapes for RT11 and TSX11 plus sundry other > docs. I need the space, how can I dispose of them free to a good home. > > I can also give you a contact for 2x pdp11/24 and 1x pdp11/34 but they > may have been disposed of already. > > ----------------- > Mike Moorhead Gloucester, United Kingdom

18 years, 5 months

Available Fw: LSI 11-83 and more stuff

by jwest＠classiccmp.org

Contact original poster directly... gear is in Tracy, Ca. Jay West ----- Original Message ----- From: "Taylor, Joe (US SSA)" <Joe.Taylor at baesystems.com> To: "Jay West" <jwest at classiccmp.org> Sent: Tuesday, November 13, 2007 11:26 AM Subject: RE: LSI 11-83 and more stuff > Hello Jay, > I got one machine with several cpu's, Memory cards, Hard disk and > controller, and serial cards. It is not a Dec chassis but some other > builder but most of the boards are Dec. I think I even have a extra > power supply and some software (RT-11 and RTS) but I will have to look > for that. Not much documentation I have one PDP-11 cpu book. > I think I even have one of the last versions of the cpu card something > like a 11-87 or something like that. > > I even have a real vt100 some place. > > I live in Tracy Ca. > > No date that I have to get rid of the stuff, I just want it to go to a > good home. I like the old machine I just don't have time to fool with it > like I would like to.

18 years, 5 months

Fw: pdp-11 in salt lake

by jwest＠classiccmp.org

Contact original poster directly... Jay West ----- Original Message ----- From: "Brad Midgley" <bmidgley at xmission.com> To: <jwest at classiccmp.org> > I rescued a pdp-11 (approx 6u rackmount size) on its way to the > landfill. The faceplate is missing and the operating condition is > unknown. I can see a full-height hard drive and some kind of tape drive > in the front. Do you know anyone who's interested in having it? > > thanks > Brad

18 years, 5 months

MMD-2 and E&L Instruments

by jwest＠classiccmp.org

I was contacted off-list by a guy who said.... "I wrote the software in the EPROM on the MMD-2 and did some PC design work for E&L Instruments way back in the 70's, so found your site really interesting. Would love to find out if anyone actually remembers those." Apparently he didn't join the list, but if someone here is keen on talking to the guy about the MMD-2 and related stuff, contact me off-list and I'll pass on his email address. Jay West

18 years, 5 months

Windoze reqs

by ajp166＠bellatlantic.net

> >Subject: Re: Windoze reqs > From: Josh Dersch <derschjo at msu.edu> > Date: Wed, 21 Nov 2007 16:11:43 -0800 > To: General Discussion: On-Topic Posts Only <cctech at classiccmp.org> > >If I may ask, what was glitchy about video modes in Windows 3.1? I ran >it at 640x480 for years without any obvious video issues... Same here, I still have a copy running on a laptop at that resolution. >As an aside, I had Win95 running on EGA for awhile just as an >experiment. On a 386sx-20 with 4mb ram on a 65MB Miniscribe MFM drive. >It ran, but that's about the only good thing I can attribute to the >experience ;). Not enough ram, at 8mb it become moderately useful. I used to make headless print network servers that way. Install 95B, strip out OE/IE and cruft install laser printer driver put on net. It usually fits well in 100MB. Prefered CPU for that was any of the miniboard 386 or 486s but one time I had a 386sx/16 brick and used it with good results (it was a slow printer to start with). The boards with 86sx were best cooling was never an issue so the fans could fail and CPU coolers were not needed. Allison >Josh > >Fred Cisin wrote: >>>> 3.00 would (and did) run on 8088. One of the font editors that I used >>>> >> >> On Wed, 21 Nov 2007, Sridhar Ayengar wrote: >> >>> Not only that, it worked properly with a CGA. >>> >> >> 3.10 would also work with CGA, but like all video modes, it was somewhat >> glitchy. It appears to me that 3.10 was written by people using >> 800 x 600. With a little playing around, it's probably not too hard to >> determine which video board they used. >> >> >> >>

18 years, 5 months

*updating* 8088's

by ajp166＠bellatlantic.net

> >Subject: Re: *updating* 8088's > From: Chris M <chrism3667 at yahoo.com> > Date: Fri, 23 Nov 2007 12:49:01 -0800 (PST) > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > > >--- Allison <ajp166 at bellatlantic.net> wrote: > >> The one I have has an 8088, model 8530-002. Well >> actually I pulled >> the board out to use the case for an SB180 with >> Adaptec SCSI/MFM >> adpator, a Miniscribe 20mb disk plus reusing the >> 3,5" disk and >> power. Made a nice case for that. Been stripping >> the PCs board >> since. > > For one those are not vanilla floppy drives, unless >I'm seriously mistaken. If that thing has an 8088, I >want a picture. We all make mistakes, I'm not trying >to harangue, but I've never heard of any PC/2 sporting >an 8088. > Are you sure it's a PC/2 (you know what I mean - PS/2)? Yes it is. If you want a picture send a camera, no digital picturs possible, USB camera not an option OS is NT4. Allison > > > ____________________________________________________________________________________ >Be a better sports nut! Let your teams follow you >with Yahoo Mobile. Try it now. http://mobile.yahoo.com/sports;_ylt=At9_qDKvtAbMuh1G1SQtBI7ntAcJ

18 years, 5 months

Vintage computer bounty: go east, young man?

by sellam＠vintagetech.com

I was reading this article: http://www.breitbart.com/article.php?id=2007-11-18_D8T08P0O0&show_article=1 ...and was wondering how many vintage machines one could find if they traipsed around China for a summer and visited all the various e-waste processing gulags that (litterally) litter the country. There is literally billions of pounds of e-waste entering China every year. If even a fraction of a fraction of that is old systems that are worth collecting and a fraction of that is still in some sort of complete and unwrecked condition, there is a vintage computer bounty waiting to be plundered by a brave privateer. The trick is getting it back to your place of origin ;) -- Sellam Ismail Vintage Computer Festival ------------------------------------------------------------------------------ International Man of Intrigue and Danger http://www.vintage.org [ Old computing resources for business || Buy/Sell/Trade Vintage Computers ] [ and academia at www.VintageTech.com || at http://marketplace.vintage.org ]

18 years, 5 months

FD400 drive troubleshooting

by dm561＠torfree.net

---------Original Messages: > From: dm561 at torfree.net > To: cctalk at classiccmp.org > Date: Sun, 25 Nov 2007 06:44:14 -0500 > Subject: RE: FD400 drive troubleshooting <snip> >>>> Which just happens to be the ratio of 300RPM vs 360RPM, so that on a 300RPM >>>> strobe disk w/a 60Hz light the 60Hz bars = 300RPM and the 50Hz bars = 360RPM. >> Hi >> I think you have the ratio backward. The 60 Hz disk for 360 RPM >> can be used for the 50 Hz 300 RPM. >> Dwight <snip> Hi I guess my problem was reading your sentence. It just isn't clear to me where you are saying they are equal and where they are not. The part "60Hz bars = 300RPM and the 50Hz bars = 360RPM" seems to be saying that "300RPM @ 60Hz = 360RPM @ 50Hz". I'm sure I'm reading it wrong but it is still confusing. At least we both agree on the basics and that is all that counts. Dwight --------Reply: Well, I did say "the 60 and 50Hz *BARS*" (as in "stripe" or "band") at the same frequency of illumination (60Hz), but perhaps I should have inserted "the speed at which the bars seem to stop" instead of trying to keep it short and simple (with exactly the opposite effect). OK, how about this: It just so happens that the ratio of 360RPM to 300RPM is the same as 60Hz to 50Hz. Therefore, if you have a strobe disk for a 300RPM drive with both 50Hz and 60Hz bars on it and a 60Hz source of illumination, then you can use the same disk to check the speed of a 360RPM drive, since at 360RPM the 50Hz bars will appear to be stationary. I'm talking about using a 300RPM disk at 60Hz (for the OP and others trying to check the speed of a 360RPM FD400 or equivalent with 60Hz); you seem to be talking about using a 360RPM strobe disk (if you found one) at 50Hz, a somewhat different situation albeit one taking advantage of the same "coincidence". But I think by now both our points have been made abundantly and painfully clear, and I'm glad that we can finally put it to rest and not clutter up the archives further. m

18 years, 5 months

FD400 drive troubleshooting

by dm561＠torfree.net

------------Original Message: Date: Sun, 25 Nov 2007 09:59:52 -0800 From: dwight elvey <dkelvey at hotmail.com> Subject: RE: FD400 drive troubleshooting > BTW, you're wrong; it's 45.1127819548872180451127819548872 > ;-) > m > Hi My calculator didn't show any more digits but your results show that the sequence repeats at 112781954887218045. If I could type underline, one could underline that part and type ... This would indicate a repeating sequence and be even more exactly correct ;) Dwight -----------Reply: You're absolutely right! Uncle! m

18 years, 5 months

Programming skills (was: Teaching kids about computers...)

by dm561＠torfree.net

Date: Sun, 25 Nov 2007 08:44:13 -0700 From: woodelf <bfranchuk at jetnet.ab.ca> Subject: Re: Programming skills (was: Teaching kids about computers...) M H Stein wrote: >> Why the "but"? Did I imply anything of the sort? Did I say that a >> carpenter should know how to make an electric saw or even repair >> it when it would be a more efficient use of his time and skills to just >> take it to a shop or buy a new one? >> ------ >But it does help if knows how to change the blade. :) >Same with hardware/software -- know your tools. I thought "being proficient in the use of the appropriate tools" kind of implied that... But thanks for making it clear! m

18 years, 5 months

trs80 items wanted

by g-wright＠att.net

-------------- Original message from "Jay West" <jwest at classiccmp.org>: -------------- > At VCFX I was able to get the last major component for my TRS80 setup > (already have the monitor, drives, and expansion interface). I got the > keyboard unit for $20. > > Looks like all I'm missing is a real tandy power supply for the Model 1 > (yes, I know I can rig something up, but I'm looking for the real mccoy), > and the buffered cable between keyboard and expansion interface. > > Anyone have one of those two items and is willing to trade? > > Jay West > > Jay, I offered you these last month ??? keyboard, PS . you would just have to take the whole expansion unit. not just the cable. never heard back ??? - jerry

18 years, 5 months

Teaching kids about computers...

by evan＠snarc.net

One of our prize sponsors at VCF East was a company called Minds-On Toys (as a play of the phrase "hands-on") ... The owner, Tim Walker -- if I recall correctly -- went to MIT and studied all sorts of educational topics. He now sells the Digi-Comp replica. It is VERY easy to build and teaches kids about binary math.

18 years, 5 months

FD400 drive troubleshooting

by dkelvey＠hotmail.com

> From: cclist at sydex.com > To: cctalk at classiccmp.org > Date: Sun, 25 Nov 2007 10:11:29 -0800 > Subject: RE: FD400 drive troubleshooting > > On 25 Nov 2007 at 9:50, dwight elvey wrote: > >> I was thinking about Tony's idea of the multiple and it occurred >> to me that there was an issue. We've been thinking of the >> flashes as instantaneous strobes while they have duration. > > Dwight, I think it's worse than that. There's also the idea of > "persistance of vision" that gets in the way and also makes the > strobe disc work--our eyes do not have instantaneous response and the > only reason a strobe disc really works is because a fixed pattern is > drilled into our optic nerves many times per second. Were this not > the case, one could have a 45 RPM strobe disc, not with 400 bars, but > with, say 4 or 50--but our eyes would likely not register these as a > single continuous event. > > Of course I haven't tried this yet and I really should. > Hi That is why I think the spiral with bars would work the best. Persistance from adjacent bars would only be a small issue at the tops and bottoms of the bars. The eye would tend to follow the spiral. Such spirals could be made for any RPM. In the case of disk drives, one could make three different spirals. Each for a percentage below and a percentage above the exact one. This way, one could quickly see if the speed were within a specific tolerance. Dwight _________________________________________________________________ Put your friends on the big screen with Windows Vista? + Windows Live?. http://www.microsoft.com/windows/shop/specialoffers.mspx?ocid=TXT_TAGLM_CPC…

18 years, 5 months

FD400 drive troubleshooting

by dkelvey＠hotmail.com

> From: cclist at sydex.com > > On 24 Nov 2007 at 22:27, dwight elvey wrote: > >> I got my math wrong. The fellow is also wrong. >> 45/60 = .75. >> 100/.75 = 133.333.... >> If rounded to 133, you get 45.11278195---- >> Still, using Tony's multiple method, 400 dots >> would work fine. It would be a large disk but >> it would work. > > 45 rpm is 0.75 r/sec. The strobe lamp flashes 100 times per second > (50Hz * 2). So, the disc completes 3 complete revolutions in 4 > seconds. During those same 4 seconds, the lamp flashes 400 times. > > So there needs to be 400/3 bars on the disc if there is to be a bar > exactly underneath the lamp for every flash, or 133.3333 bars, which > causes the problem. If we increase the number of bars to 133 > exactly, the disk will be turning at 100/133 = 0.75188 r/sc or about > 45.1128 rpm. > > If we put 400 bars on the disk, the lamp will flash once for every > third bar passing under it. Not the crisp display we were hoping > for, however--and I don't know what the visual error would be without > trying it. > > At least that's how I compute it. So maybe the guy is right. > Hi Chuck I was thinking about Tony's idea of the multiple and it occurred to me that there was an issue. We've been thinking of the flashes as instantaneous strobes while they have duration. This would, as you state, cause a loss of contrast. This would tend to overlap the dots and white space of adjacent dots. This would indicate that a continuous 400 dots would most likely work poorly. Still, the spiral method should work fine, with just as much contrast as the single row method. One could use the original size dots and spacing. So, I feel that the fellow was incorrect that such a strobe disk could not be made for exact 45 RPM. Now, looking at the 78 RPM problem, the task seems more difficult, for both 60Hz and worst for the 50Hz. Still, three or four spirals with the correct spacing would be enough, even if it didn't come out to a nice integer. Dwight _________________________________________________________________ Share life as it happens with the new Windows Live.Download today it's FREE! http://www.windowslive.com/share.html?ocid=TXT_TAGLM_Wave2_sharelife_112007

18 years, 5 months

FD400 drive troubleshooting

by dm561＠torfree.net

---------Original Message: Date: Sat, 24 Nov 2007 22:27:04 -0800 From: dwight elvey <dkelvey at hotmail.com> Subject: RE: FD400 drive troubleshooting > http://www.extremephono.com/free_turntable_strobe_disk.htm > > Note that the 50Hz disc is 45.11 RPM > > Cheers, > Chuck > Hi I got my math wrong. The fellow is also wrong. 45/60 = .75. 100/.75 = 133.333.... If rounded to 133, you get 45.11278195---- Still, using Tony's multiple method, 400 dots would work fine. It would be a large disk but it would work. Dwight -----------Reply: If you're saying that he's wrong, that it's not 45.11 but should be 45.11278195 then I can see why you & I are arguing over whether 300/50 = 360/60 or 360/60 = 300/50... BTW, you're wrong; it's 45.1127819548872180451127819548872 ;-) m

18 years, 5 months

FD400 drive troubleshooting

by dm561＠torfree.net

---------------Original Message: Date: Sat, 24 Nov 2007 10:02:54 -0800 From: dwight elvey <dkelvey at hotmail.com> Subject: RE: FD400 drive troubleshooting >> From: dm561 at torfree.net > ------------Original Messages: >>> Date: Thu, 22 Nov 2007 12:17:31 -0800 (PST) >>> From: Fred Cisin >>> Subject: Re: FD400 drive troubleshooting >>> >>>>Many/most drives have 50Hz/60Hz zebra discs on the flywheel, for using a >>>>flickering fluorescent light. >>> >>> Which just happens to be the ratio of 300RPM vs 360RPM, so that on a 300RPM >>> strobe disk w/a 60Hz light the 60Hz bars = 300RPM and the 50Hz bars = 360RPM. >>> >>> FWIW, >> >> Hi >> I think you have the ratio backward. The 60 Hz disk for 360 RPM >> can be used for the 50 Hz 300 RPM. >> Dwight >> >> ----------Reply: >> Well, unless you're just saying that a 60Hz 360RPM strobe disk (if you had one) >> would also sync at 300RPM under a 50Hz light, I don't see what's backward. >Hi > That is what I said. The disk with 20 bands would work for both >a 360 RPM and 60Hz light or a 300 RPM and 50 Hz light. -------- Gee, I thought that was what *I* said (and you claimed was backward). Let's see; I said that 300RPM @ 50Hz = 360RPM @ 60Hz, and you said that's backward - 360RPM @ 60Hz = 300RPM @ 50Hz. Sounds like the same thing to me (and Tony) except that a 360RPM strobe disk is a lot harder to find than a 300RPM. Sheesh... --------- > Tony mentioned that one could increase the number of bands for the >problem of the 50Hz with a 360 RPM drive. It makes sense. -------- Indeed; glad to hear it. ------- > Tony mentioned that most 8 inch drives were speed controlled by >the mains and as long as the belt was in good shape, using a strobe >wasn't much needed. ----- You really should read more carefully; he didn't say "most," he said "all of mine," referring to his particular collection. In fact, many 8" drives were 24VDC powered, including the Pertec FD400 which prompted me to send (and regret) the original post that started this bizarre exchange... m

18 years, 5 months

Babbage Calculating Machine Article 1833

by evan＠snarc.net

I'll send you a private message with contact info for Doron Swade. He will know the answers to your questions. -----Original Message----- From: "B. Degnan" <billdeg at degnanco.com> Subj: Babbage Calculating Machine Article 1833 Date: Sun Nov 25, 2007 9:44 am Size: 2K To: cctalk at classiccmp.org New York Weekly Messenger 2-13-1833 Babbage Calculating Machine Article 1833 On the back page of this newspaper is an article that describes in some detail the eye-witness account of a *working* machine: "...the greater part of the calculating machine is already constructed....I have had the advantage of seeing it actually calculate, and of studying its construction with Mr. Babbage himself..." Does this account describe a working computer? To help make this determination I would want to learn more about the error checking capability of this machine, which I assume was used for calculation of significant digits. A described, Babbage's calculating machine could be described as "computer-like" at least. I believe that this article reports the closest Babbage got to a actual working computer. Or just an elaborate calculator. There are no references in the article to what we today would identify as punch cards or programming. Download the PDF http://www.vintagecomputer.net/babbage/charles_babbage_2-13-1833.pdf ...and read for yourself. The article describes error checking and how results are viewed and how log tables could be calculated accurately, for use in astronomy. The article noted that regarding the printer "..less progress was made...". In the 1830's news from Europe would take a few weeks to reach New York, as boat was the only cross-Atlantic communications. Most articles in the paper refer to end of December 1832 events, including the account of the Calculating Machine. Overall there was a lack of contemporary articles about Babbage's calculating machine in 1832-35. I was able to find just the one often quoted article by D Lardner: "Babbage's Calculating Engines" from the Edinburgh Review 59 (1834) pg 263-327. The New York Weekly Messenger article above was printed a year prior, making it among the first known articles about Babbage's calculating machine. The apparent lack favorable press and the loss of funding in 1834 obscured the fact that the machine had a working visual "display" and was probably more complete than people realize. Was the calculating machine programmable? Maybe. Most writings about the Babbage projects were published a generation after the project was cancelled and I don't think that it's possible to discount the notion entirely.

18 years, 5 months

Booting XXDP+ from a secondary controller

by bqt＠softjar.se

"Bob Armstrong" <bob at jfcl.com> skrev: > Is there a way to boot XXDP+ from a secondary MSCP controller (e.g. CSR at > 760334) ? > > > > This isn't a PDP-11 boot ROM issue - the -11 (a 11/53+ in this instance) > ROM has no problem booting from a secondary controller. > > > > The issue is that, once started, XXDP doesn't know that it should talk to > this alternate CSR address and promptly dies. I don't think so. As far as I know, XXDP don't take any hints from the boot rom code. You need to build a specific XXDP distribution with a monitor using a device driver talking to the controller at that alternate address. Not sure how you would do that. I've never tried getting system device drivers in XXDP to talk to devices at other than standard addresses. Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt at softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol

18 years, 5 months

Booting XXDP+ from a secondary controller

by bob＠jfcl.com

> Glen Slick (glen.slick at gmail.com) wrote: >On simh it appears that attaching the disk to rqb0 >resulted in a unit 0 drive on the secondary MSCP controller and I >couldn't find any options to configure the unit number. Does XXDP require all MSCP unit numbers be unique? I thought that was just RSTS... You can do this in simh by attaching the xxdp25.rd52 image to the device rqb2, since the primary rq controller just uses drives 0/1. When I did this, I got the same result (i.e. a halt) as before. >Have you tried this on the real hardware yet? On the real hardware >what unit is the drive you are trying to boot on the SQ703? Yes, on the real hardware it doesn't halt; it just seems to hang forever. The dialog goes something like this (I'm retyping this from my VT320, so excuse any typos) - Commands are Help, Boot, List, Map, Test and Wrap. Type a command then press the RETURN key: B/A DU2 Address = 17760334 DU2 ... hangs here .... BTW, I was wrong before; my SCSI controller is actually a SQ739 rather than a 703, but I doubt that changes anything. There are two SCSI devices on the SQ739, an Exabyte 8505 tape drive and a RRD43 (a Toshiba something or other) CDROM. The SQ739 is configured for 17760334 for MSCP and the RRD43 is configured as MSCP unit 2 (i.e. DU2). Maybe there's something wrong with the way I'm making the CD image? Did you do anything special when you made yours? Thanks, Bob

18 years, 5 months

Jump to page:

2026

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

1997

test-drb