test-drb February 2007

test-drb@ccmp.vtda.org

208 participants
390 discussions

by dm561＠torfree.net

>Date: Sun, 04 Feb 2007 14:56:01 -0800 >From: "Chuck Guzis" <cclist at sydex.com> >Subject: Re: Arty computers >Didn't the GI CP1600 have an external line that, if activated, would >inhibit P-counter increment? I don't know if anyone ever used it for >anything. >Cheers, >Chuck ------------------------ My, what a remarkable memory you have: pin 40, /PCIT (Program Counter Inhibit), also used to output a pulse on execution of an SIN (software interrupt) instruction, apparently used mainly by the control console. mike

17 years, 10 months

Arty computers (was: Re: PDP-11/70 in Yates Center, KS)

by mtapley＠swri.edu

At 19:45 -0600 1/30/07, cctalk-request at classiccmp.org wrote: >I've often thought that you can see the beauty of machinery (including >computers) on many levels. Most classic computers are not particularly >beautiful to look at, but there can be beauty in how they're assembled (I >personally think the HP9816 is an interesting construction), there can be >beauty in the elkectronic design, or the firmware, or... You just have to >look for it. Agreed, which leads me to NeXT cube as my nomination. Though the mainboard design is not a particular standout, chassis design, appearance, and software all appeal strongly to my aesthetics. I quail at the thought of suggesting a thread on "performance arty" computers... (...or "artless" computers. TRS-80 model 1?) -- Mark Tapley, Dwarf Engineer (I haven't cleared my neighborhood) 210-379-4635 Dwarf Phone, 210-522-6025 Office Phone

17 years, 10 months

arty computers

by aliensrcooluk＠yahoo.co.uk

--- "G Manuel (GMC)" <gmanuel at gmconsulting.net> wro te: > > > -----Original Message----- > From: aliensrcooluk at yahoo.co.uk > [mailto:aliensrcooluk at yahoo.co.uk] > Sent: Friday, February 02, 2007 6:59 PM > To: cctalk at classiccmp.org > Subject: Re: arty computers > **>> snip <<** > >Regards, > >Andrew D. Burton > >aliensrcooluk at yahoo.co.uk > > >PS. Does anyone know what has happened to > >the Old Computer Museum? I can't connect to it? > > Do you mean www.oldcomputermuseum.com? It works fi ne > for me. > > Greg > Ok, I can connect, but I get redirected to here: http://www.oldcomputermuseum.com/files/error.html I'm on dial-up and am from the UK. That shouldn't ma ke a difference should it??? Does anyone know if the site has been altered/ upgraded recently? Regards, Andrew D. Burton aliensrcooluk at yahoo.co.uk

17 years, 10 months

TRS-80 Model I

by ken＠seefried.com

From: "Ethan Dicks" <ethan.dicks at gmail.com> > >Ooh... didn't know that the M4 could run CP/M. > I ran "Montezuma" CP/M-80 exclusively on my Model 4P. I did it at first so I could use Turbo Pascal, but decided pretty quickly that I liked it better than TRS-DOS.

17 years, 10 months

CBM 8032 Garbage on Screen

by dm561＠torfree.net

--------------Original Message: From: Marvin Johnston <marvin at rain.org> Subject: CBM 8032 Garbage on Screen I've got a CBM 8032 that powers up "fine", but the screen is filled with "!" on every other character position. When some letters are repeated, they can change, i.e. "nnnn" becomes "onon" which seems like (without checking the ASCII charts) that the "n" and "!" are ORed to become the "o". Anyone have any ideas what the problem might be? Most of the schematics I have are buried someplace, so I thought I would start here. --------------------- My guess would be a stuck bit D0 in UC4 (even chars) or UC6 (odd chars), a 2114, notorious for its failure rate. mike

17 years, 10 months

TRS-80 Model I

by buseyl＠yahoo.com

--- Tony Duell wrote wrote: > > Interesting. Most people seem to say nice things > about > > the Apple ]['s design. I'd love to hear some > informed > > bashing ;) . Could you elaborate some about the > > machine's short comings from your perspective? > > Firstly let me emphasise that my first computer was > a > TRS-80 Model 1. And > I thus do have a soft spot for that machine. > Irrational, probably, but > there you are. I've got several TRS-80s now (M1, M3, > M4, CoCo, M100) and > all have proved _very_ reliable. Odd considering > other > people's > expieneces, but I must have replaced perhaps a dozen > components _total_ > in all said machines. I see nothing wrong with that. The Tandy machines seemed like decent computers for the money. I wouldn't mind picking up a TRS-80 someday. > Now, the Apple ][... > I had a lot of rpboelsm with it randomly crashing. > In > the end I took the > whole thing apart and stuck an ammeter in the 5V > output of the power > supply. It turend out that the mainboard (48K RAM) + > languge caed + 1 > floppy drive drew _more_ than the rated current of > the > supply as given in > the techincal manual If you added more drives, a > serial card, etc, it > became ridiculous. Strange, I haven't noticed any stability problems with my ][ and ][+ under similar loads. Still, an unstable machine is unlikely to impress. > Much has been said about the Apple ][ disk > controlle, > and how it's a > clever design. Well, a minimal-component design > certainly, but I didn't > like it. Not having a track0 sensor seemed like a > Bad > thing for starters > (continually banging the head against the stop does > not improve the > alignemnt!). The drives are Shugart mechanisms with > the IMHO poor > plastic-cam-with-a-spiral-groove head positioner, > and > becuase the drives > are non-standard you can't use any others (unlike > the > TRS-80 where you > can use any 5.25", 3.5" or 3" drives). But for me > the > biggest problem was > that the Apple couldn't read/write disks from other > machines, unlike the > TRS-80, which used a WD1771 controller and could > handle any single-desity > 5.25" disk (I spent many late nights getting it to > read the disks from > the school's RML380Z computers, which also used 1771 > controllers). What can I say? The Disk II, either you love it or you hate it. :) To be fair though, the Apple Disk II system was not the only game in town. While they weren't common, you could get a 3rd party 8" MFM floppy system if you wanted to. Would you recoil in horror if I told you that some companies made single sided 40 track 3" (Amdisk) and double sided 80 track 5.25" (Rana Elite 3) drives for use with the original Disk II controller? ;) > I didn't like the Apple ][ I/O system. Memory space > was tight, but they > wasted lots of space with those 'soft switches' and > single-bit inputs. It > could all have been packed into a few bytes. I am > pretty sure the 6821 if > not the 6522 was available when the Apple ][ was > designed. Fair enough. > The first seiral port for the Apple ][ was a > bit-banger. It was the only > one I had for some time, and it was almost unusable. > The TRS-80 used a > real UART, and worked. Yes, there were better serial > ports avaiable for > the Apple later. Was this an early serial board or were you using the game port? I've always enjoyed the luxury of a 6551 equiped board (Super Serial Card II). I think Woz was allergic to peripheral chips in the beginning. :) > The Apple text display did have lower case (wich the > TRS-80 didn't as > standard), but you couldn't mix text and graphics on > the same part of the > screen. Apple gave you the high-res mode, but > working > out the addresses > gave me headaches (all to save a few chips IMHO!). > And > colours in the > high-res mode were essentially obtained as NTSC > artefacts. The TRS-80 graphic characters are pretty neat. The stock Apple character generator was certainly poor in terms of graphics characters. Heck, it didn't have lower case characters! Needless to say, soft hires character generators were a pretty common project. It would have been nice to have had one in the firmware. The hires mode is somewhat byzantine and it was indeed that way to save chips! :) Fortunately, it's not too bad to work with if you use a lookup table to untangle the memory map. I have no doubt it has turned off plenty of people though. The colors are NTSC artifacts! :) I thought that was a neat hack. How did they deal with that in PAL land? > And another oddiity. The whole design of the Apple > ][ > seems to have been > to save a chip if at all possible (provided the > machine still works -- > just). Bingo! Legend has it that Woz's aesthetic ideal was to bum a design down to as few chips as possible. Almost a Madman Muntz I suppose. Methinks you're not a fan of Clive Sinclair either? :) And yet the kayboard was encoded in hardware. > Why? It meant you > couldn't implelement a lower case keyboard in > software > (there are the > well-known shift key mods where you run a wire from > the shift keyswitch > to one of the single-bit inputs on the games > connector, which shouldn't > have been necessary). This is a good point. My guess would be that Woz designed the Apple II as just a naked board, kind of like the Apple I. Apple sold you the motherboard and it was up to you to find a power supply , keyboard, and housing. Apple did offer the ][ that way early on. > Of course I like elegant, simple designs (the HP9100 > is a case in point). > But the Apple ][ seems to have been a case of > cutting > too many corners. > And I had a lot of problems as a reuslt. > > -tony Thanks for your input Tony. While I've never had reliability problems with my ][/ ][+ I think I understand where you're coming from. I like the Apple because I feel it's a machine with interesting capabilities yet made from a small amount of simple parts. It's a machine I can both grasp and enjoy. What's your opinion of the BBC Micro? I've never had the pleasure of using one, but on paper it sounds a lot like a fast Apple II with a pair of 6522, 6845, hardware ACIA, 1770 FDC, and enhanced basic. Liam Busey ____________________________________________________________________________________ Sucker-punch spam with award-winning protection. Try the free Yahoo! Mail Beta. http://advision.webevents.yahoo.com/mailbeta/features_spam.html

17 years, 10 months

Ampex Timeline

by roger.holmes＠microspot.co.uk

On 4 Feb, 2007, at 18:15, cctalk-request at classiccmp.org wrote: > > Message: 7 > Date: Sun, 04 Feb 2007 12:52:33 -0500 > From: "Bob Bradlee" <caveguy at sbcglobal.net> > Subject: Re: Ampex Timeline > To: "General Discussion: On-Topic and Off-Topic Posts" > <cctalk at classiccmp.org> > Message-ID: <200702041754.l14Hsgkx054201 at keith.ezwind.net> > Content-Type: text/plain; charset="us-ascii" > > On Sun, 04 Feb 2007 09:32:29 -0800, Chuck Guzis wrote: > >> Another possiblity--the Ampex tape drives wouldn't have been standard >> at the time; it would have been IBM 729's. > > Although there is little online about the earlt Ampex drives > because they were goverment only. > > The following id from the Ampex timeline: > > 1950 Ampex introduces the first "dedicated" instrumentation > recorder, Model 500, built for the U.S. Navy. > > 1954 Ampex introduces the first multi-track audio recorder derived > from multi-track data recording > technology. > > Some food for thought ... > > Bob The machine in question was I understand 1959/60. I don't know the official release dates for the digital Ampex drives but ICT used them on the ICT1301 which was released in 1962, though the tape drives were not immediately available. These were one inch tape drives (Ampex TM1 I think) and half inch drives (Ampex TM4). These used the aluminium spools with three notches in the hub not the later industry standard expanding hub type spools. The one inch tapes were 16 track and the half inch tapes were 10 track. They used thyrotron valves to fire the pinch rollers. The TM4s also had a version used on the Lyons Leo computers of that era, these used the same tape spools but with a small expanding hub, like a scaled down version of the 7 track and 9 track ones. Professional reel to reel audio equipment used a quarter inch version of the same spools until recently, or maybe they still do for all I know about audio recorders. By the way, as Dr Who has been deemed to be on topic: ICT 1301 consoles appeared on Dr Who and Blakes 7. I think I saw one in a James Bond film too, but I have been trying to find which one but have so far drawn a blank. In the villains HQ there was a big round room on two floors and in the middle were some control panels, the whole place got blown up as is normal in a 007 film. Must have been filmed about the time 1301s were being scrapped 1965 to the early 70s. Roger Holmes (owner of an ICT 1301 for over 30 years)

17 years, 10 months

TRS-80 Model I

by chrism3667＠yahoo.com

the Peanut was a *mostly compatible*, no? I thought the main hindrance to running pwogwams was the lack of a 2nd floppy or hard drive... ____________________________________________________________________________________ Be a PS3 game guru. Get your game face on with the latest PS3 news and previews at Yahoo! Games. http://videogames.yahoo.com/platform?platform=120121

17 years, 10 months

TRS-80 Model I

by chrism3667＠yahoo.com

the Peanut was a *mostly compatible*, no? I thought the main hindrance to running pwogwams was the lack of a 2nd floppy or hard drive... ____________________________________________________________________________________ Have a burning question? Go to www.Answers.yahoo.com and get answers from real people who know.

17 years, 10 months

Apple Disk II, was Re: TRS-80 Model I

by marvin＠rain.org

> From: Liam Busey <buseyl at yahoo.com> > > But for me the biggest problem was > > that the Apple couldn't read/write disks from other > > machines, unlike the > > TRS-80, which used a WD1771 controller and could > > handle any single-desity > > 5.25" disk (I spent many late nights getting it to > > read the disks from > > the school's RML380Z computers, which also used 1771 > > controllers). > > To be fair though, the Apple Disk II system was not > the only game in town. While they weren't common, you > could get a 3rd party 8" MFM floppy system if you > wanted to. Lobo Drives made drives for, among others, the Apple II including a neat box with an 8" floppy drive and an 8" hard disk. They were given to me to sell on Ebay, and then the guy passed away (same person who gave me all the Poly stuff, and lots of other things before he died.) I have them set aside until either I have the time to find out more about how to hook it up, or someone drops by who knows what they are doing. My suspicion is that the hard drives probably have a lot of interesting things from Lobo Drives, hence my caution. And I *think* I have the controller card, but again, I need to research this stuff out.

17 years, 10 months

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test-drb February 2007