test-drb

test-drb@ccmp.vtda.org

101090 discussions

by dave＠mitton.com

I'm trying to get rid of some older computer magazines to anyone interested in picking them up (Northwest of Boston) or paying Media mail rates. PC Tech Journal 1985 thru 1989v4 with a couple missing 1988 issues and 1984 v1 & v6. Dr Dobbs Journal: 1976 v1 book reissue & Mar, Sept, Oct and most of years 1977 thru 1985 I also have many issues of S-100 Microsystems/Microsystems/Microsystems Journal for 1980 thru 1988. I filled in the missing issues at the CHM and therefore the list is now full of holes. Exact issue counts available upon request. Dave

18 years, 2 months

Fwd: Xerox 1186 LISP machines in Illinois

by mtapley＠swri.edu

All, Possibly redundantly to some of you, I'm passing on this email, which I received this morning (presumably due to my presence on the Color Computer or Classic-Comp rescue lists). The systems are in southern Illinois, according to a later exchange with the offerer. Diana included a set of pictures with the first email, which I'll be happy to forward if you are interested, but I strongly suggest you contact her directly. I have no connection to her or previous acquaintance with her. >Date: Thu, 24 Jan 2008 09:31:52 -0600 (GMT-06:00) >From: Diana Moutell <dmoutell at earthlink.net> >Subject: Xerox 1186 LISP machines > > Hello!! > > >I wondered if you had an interest in the Xerox 1186 produced around >1986. Pictures are attached. I know they are quite uncommon. I have >7 of the computers... one monitor.... and now one keyboard. I just >found the keyboard... and an amazing amount of literature, manuals >and software (in addition to what is in the one picture). I >literally have mountains of manuals and boxes of software... really >large floppies and then the smaller ones I remember from my first >computer days (the 5 inch ones) !! I have yet to look through it all >and determine what is there. > >All of the Xeroxes I have are pretty much the same except some are >missing the C7 rigid 80Mb disk. I took pictures of the back of one >with the drive and one without the drive. The product code on the >one pictured with the C7 is 62H. Some of them have a panel over the >place that contains C6 and C7. I did not remove it and I am not sure >I can easily. I believe the person who had them had them all >together. > > >There are only two external hard drives that attach to the back - >the product code on the bottom of the one is 78D. There is a picture >of one of them. I know that they have had one owner and have been in >one general area since the beginning. I believe they have been moved >twice in their life after the initial delivery. > > At this time I do not know if any will power up. I believe I found >their original power cords.... but I do know that the hard drives >have been erased because the data that had been stored on them was >of a private research based nature. I will try some soon. > > They are heavy and really take the space... but I, as a collector >of hundreds of things, am accustomed to tripping over my stuff!!! I >only have received a couple of bruises from these and their >acquisition! I do not collect computers, though. However, as I look >at them and all the stuff with them... I and my friends fear that I >will become attached to them, and never be able to let them go. >However, my intent is to sell them. I have seen so many sites of >individuals who have such a love for saving, protecting and >restoring these things. My collections are really just to admire not >to repair or use. In fact, I am oftened asked "does it work" when >people look at my stuff (especially the vintage radios) and my >answer is " I do not know." Most of the have never been plugged in >at all. I just want them because they are beautiful. > >If I do let go of these... I want to know they will be safe for eternity. > >If you are interested in more info... let me know and when I learn >more and compile the list of literature... I will send it to you. > > >Thanks!! >Diana > > >Diana Fuller-Moutell ><mailto:dmoutell at earthlink.net>dmoutell at earthlink.net >Why Wait? Move to EarthLink. > -- - Mark, 210-379-4635 ----------------------------------------------------------------------- Large Asteroids headed toward planets inhabited by beings that don't have technology adequate to stop them: Think of it as Evolution in Fast-Forward.

18 years, 2 months

DEC Professional 350 help

by thrashbarg＠kaput.homeunix.org

Hi, I've had a very dead DEC 350 in the shed for a while now and I've just had a look at it, there are a lot of chips on it I can use. But before I give everyone here a heart attack, is there any chance of rescue? When I turn it on the 4 numbered LED's come on immediately, as does the green DC light. Then nothing. Not a blip. I tried removing all unneeded cards and still nothing. Is this thing absolutely dead? Or can it be saved. Also, is there any information for the three LSI-11 chips on it - pinouts etc? I haven't been able to find anything about them anywhere. Perhaps they remained proprietary to DEC. I'd like to see them out of curiosity, and if the 350 itself proves to be completely dead I'll see if I can wire them up on some prototype board and have a play around. One chip is labeled (perhaps it's a FPU, I don't know) DEC 304 E 21-15542-01 6436-40 I 8352 (that looks like a date code) The other two have two dies each (which I guess is the processor itself) IC 1, Left (closest to pin 1): DEC 303E 23-001C7-AA 6319-29 8348 TIWAN (date code again) Right: evidence of a label exists, but it's unreadable IC 2, Left: DEC 303E 23-002C7-AA 6587-03 8425 Right: DEC 303E 23-203C7-AA 6638-10 8422 there is also some print on the ceramic itself IC1: 57000001A1 and a date code IC2: 57000101A1 date code Any information about these chips or the DEC Pro 350 is appreciated! Thanks, Alexis.

18 years, 2 months

Xerox 1186 LISP machines available in southern Illinois

by frustum＠pacbell.net

I received an email that has sent to a number of other folks, but but apparently there are no takers yet, and Xerox computers aren't up my alley. I asked and she said it would be OK to forward her email to the list. If you are interested, and really can give these machines a caring home, and not just space in your trophy collection, please let me know and I'll forward your contact information to the sender and she can sort out who should get it. (quote) I wondered if you had an interest in the Xerox 1186 produced around 1986. Pictures are attached. I know they are quite uncommon. I have 7 of the computers... one monitor.... and now one keyboard. I just found the keyboard... and an amazing amount of literature, manuals and software (in addition to what is in the one picture). I literally have mountains of manuals and boxes of software... really large floppies and then the smaller ones I remember from my first computer days (the 5 inch ones) !! I have yet to look through it all and determine what is there. All of the Xeroxes I have are pretty much the same except some are missing the C7 rigid 80Mb disk. I took pictures of the back of one with the drive and one without the drive. The product code on the one pictured with the C7 is 62H. Some of them have a panel over the place that contains C6 and C7. I did not remove it and I am not sure I can easily. I believe the person who had them had them all together. There are only two external hard drives that attach to the back - the product code on the bottom of the one is 78D. There is a picture of one of them. I know that they have had one owner and have been in one general area since the beginning. I believe they have been moved twice in their life after the initial delivery. At this time I do not know if any will power up. I believe I found their original power cords.... but I do know that the hard drives have been erased because the data that had been stored on them was of a private research based nature. I will try some soon. They are heavy and really take the space... but I, as a collector of hundreds of things, am accustomed to tripping over my stuff!!! I only have received a couple of bruises from these and their acquisition! I do not collect computers, though. However, as I look at them and all the stuff with them... I and my friends fear that I will become attached to them, and never be able to let them go. However, my intent is to sell them. I have seen so many sites of individuals who have such a love for saving, protecting and restoring these things. My collections are really just to admire not to repair or use. In fact, I am oftened asked "does it work" when people look at my stuff (especially the vintage radios) and my answer is " I do not know." Most of the have never been plugged in at all. I just want them because they are beautiful. If I do let go of these... I want to know they will be safe for eternity. If you are interested in more info... let me know and when I learn more and compile the list of literature... I will send it to you. (end quote)

18 years, 2 months

BTI 8000

by aek＠bitsavers.org

> Ron Crandall. > Since much of the team came from > the same school in Oregon and worked on the same system, the 8000 > suffered a classic case of second system syndrome. "OS-3, the Oregon State Open Shop Operating System James W. Meeker, Ronald Crandall, Fred A. Dayton, G. Rose" > Also keep in mind that BTI's bread-and-butter wasn't the 8000, but the > 5000, which was essentially a clone of the HP 2100 and ran HP software... eeek! too much synchronicity going on there. HP 2000, BTI, OS-3 All systems I've been researching for a while. No wonder the names sounded familiar. I have seen the BTI 5000 front panel, looks like a simplified HP1000 one.

18 years, 2 months

Tom Poulter

by aek＠bitsavers.org

http://www.drj.com/articles/spr99/poul.htm "Tom Poulter graduated from Stanford University with a BS degree in Physics and has been BTI?s CEO for 30 years. Prior to co-founding BTI Computer Systems, Tom was employed at Hewlett Packard designing a signal conditioning product line & as Systems Product Manager for HP?s bundled computer systems including HP?s first timesharing system." Sounds like a good guy to chase down, both for BTI material and 2000 stuff, esp since HP has opened up the sources, but didn't actually have any of the early software.

18 years, 2 months

BTI 8000

by aek＠bitsavers.org

In Aug, 2004, Jim Battle wrote: > Speaking of core memory, I used to work for a company that was still > shipping core-based systems in 1985, when I first joined them right out > of college. > > The machine was the "BTI 8000", made by BTI Computer Systems, based in > Sunnyvale, CA. I worked there for only a year, but I have some > recollection of the machine. I turned up a brochure and technical summary last night, scans up under http://bitsavers.org/pdf/bti

18 years, 2 months

GE GP220 system?

by jules.richardson99＠gmail.com

Hi all, (I'm slowly getting back up to speed with the list!) Spotted in Seattle last week - a General Electric GP220 controlling a large industrial robot arm. Is anyone familiar with this beast? Is it even a computer as such? It's a big cabinet (maybe 6ft high, 3ft wide), and this one had an Apple ][ perched to one side, giving the impression of a console - but maybe the GP220 is just some sort of interface between the Apple ][ and the hydraulics of the robot arm, and the Apple actually contained all the smarts? However, there was a large hand-held controller attached to the GP220 with a big keypad and LED readouts - unfortunately the photo I grabbed was a bit too fuzzy to make much out on it (but one of the LED seven-seg displays looks to say 'program no.' underneath, implying that the system did have built-in intelligence of some kind). There's also what looked to be a built-in CRT on the front of the cabinet too, but it was covered by a large shroud and wasn't obviously displaying anything when I saw it - it could have been nothing more than a piece of glass over some mechanical readouts or something else deep within the bowels of the cabinet. Power input was a hefty 460VAC 3-phase at 40A according to the data plate. No obvious build date, unfortunately. cheers Jules

18 years, 2 months

Need 28VDC 4Amp PS...

by trag＠io.com

I saw a little more info on this topic. There are quite a few different Apple displays which use the ADC connector, and as you might imagine, the power demand of each one is different. The 17" Studio Display has a rated power demand of 40 watts, e.g.. Of course the bigger 23" displays and such will draw much more power. So, at 28V, if you could supply 1.5A you'd be okay, even with that display connected. Now, you've not going to get 1.5A at 28V stepping up the trickle supply, but the display isn't on while the computer is off, and once the computer comes on, there should be 30 or so amps available on the 5V supply. You'd just need to be sure to use a voltage booster which can handle the larger amperage and an ATX supply with a hefty 5V current rating. I think some of NS's boosters go as high as 3A. They have a nice table on their website which lists such characteristics. Jeff Walther

18 years, 2 months

Need 28VDC 4Amp PS...

by trag＠io.com

> > 22. Need 28VDC 4Amp PS... (Bill Sudbrink) > Date: Wed, 23 Jan 2008 16:52:23 -0500 > From: "Bill Sudbrink" <wh.sudbrink at verizon.net> > I'm fixing a PowerMac G4 for my Dad's wife. The original PS is dead. > It was a pretty standard ATX supply, the only difference is that it > supplies 28VDC at 4 Amps on two extra pins. Rather than spending a > lot of money on a new supply (more than $250 from the few sources that > will guarantee the PS) or a not insignificant amount on a used PS that > could go at any time, I want to put in a new standard ATX supply and > "tuck in" a small 28VDC PS to drive the two extra pins. The supply > is always on, so I can power it from a pass through on the ATX supply. > Does anyone have (or know where to get) a small supply? The 28V serves a couple of (mostly silly) purposes. Primarily it is there to supply 28V through the ADC video port so that a connected Apple display, which uses the (proprietary) ADC connector, can draw all of its power from the host Mac through the video cable at 28V. That is why the amperage rating is so high. I'm rather hazy on what the other purpose of the 28V supply is, but I'm under the impression that the machine will not start up without it. If you are not connecting an ADC based monitor, your power supply can have a much lower capacity. Which brings me to this: <http://www.io.com/~trag/28v_vreg.pdf> I did not design this, but it is a handy little circuit which boosts the 5V trickle to 28V to supply the needs which the Mac power supply has, other than powering an ADC monitor. I would not recommend connecting an ADC monitor to a Mac with this adaptation. The National Semi 2577 on which it is based is not rated to deliver 3A. You may wish to browse NS's website a bit. They have a variety of voltage boost chips available and IIRC the 2586 has a higher power rating. The ADC connector has been a curse to many Mac users. In addition to requiring the off-kilter power supply, most of the non-iMac/non-Mini Macs sold had dual video connectors but one of them was that stinkin' ADC connector. So if the user wanted two monitors he either had to buy an expensive (but fairly nice) Apple display or an expensive adapter. Furthermore, Apple routed the 28V supply to the video card through a pin which is now used on 8X AGP video cards. So one cannot install an 8X AGP card in "28V" Macs without neutralizing the 28V connection in some way. The analog video signals are present on the ADC connector, so it is possible to adapt through to plain old analog VGA, but the unusual form factor of the ADC connector means that as soon as Apple stopped hawking ADC, products, such as adapters, with the ADC connector stopped production. ADC to VGA adapters are only available on the used market now and rarely. There appears to be an infinite supply of Formac brand ADC to DVI adapters available, especially in Europe. However, for some reason the Formac (and most others) adapter does not pass through all of the analog signals. So going ADC-DVI and then DVI-VGA will not work unless one modifies the ADC-DVI adapter. I opened the thing (Formac adapter) up and it contains a small circuit board to which all the incoming analog signals are connected. It boggles me that they did not bother to connect them at the other end of the adapter. Jeff Walther

18 years, 2 months

IBM 9221 mainframe at auction

by ceby2＠csc.com

This message reminded me I have a challenge with my 9221. It takes parallel bus and tag cabling. When I bought it, I completely forgot to catalogue to the cables with the package. You guessed it, I have lots of terminal cables by not a single bus cable. So there's a CPU, expansion cage, and 5 drives, but not a thing to connect them together [silent scream]. Does anyone on the UK side of this list actually have any surplus parallel bus and tag cabling, or a source for such things? The only way I've see so far is to have them manufactured for some laughable amount of money. Regards, Colin

18 years, 2 months

Grid MS-DOS 3.3

by cclist＠sydex.com

> Date: Wed, 23 Jan 2008 18:42:26 -0500 > From: Dave Mabry <dmabry at mich.com> > Is there a chance you might put these files online again for me? Just > decided to resurrect a Grid 1535 and find I might be missing some files > that are specific to that hardware. Shows you what my own memory's like. They're still here: http://www.sydex.com/temp/griddos.zip Okay, I'll take it off *this* Friday (unless I forget). Cheers, Chuck

18 years, 2 months

Seagate ST11R ST412 controller + Mitsubishi MR535R

by peter.hicks＠poggs.co.uk

Hello! I have an elderly Mitsubishi MR535R (60Mb-ish RLL) connected to an ST11R controller. The control and data cables are homebrew although neatly and tidying put together. When I power up an old Pentium II - because it's the only box I have with ISA slots - the ST11R pops up a message on the screen, clunks the drive in an "I'm accessing you" kinda way, but then reports "No drives found" and continues merrily on its way. The cables are straight-through, and I have the drive set to DS1. If I set the drive to DS2, the BIOS sits there for several seconds but doesn't access the drive. As my knowledge is a tad rusty, can anyone help identify what the problem here is? BIOS shadowing is off for the memory locations that are, and could, be used by the card. The only thing I can think of is that the ST11R is in fact an ST11M, tries to read the drive, goes "Uh-oh, don't recognise you" and reports "No drive found". Unfortunately I lack an MFM hard drive to test this out with :( Peter -- Peter Hicks | e: my.name at poggs.co.uk | g: 0xE7C839F4 | w: www.poggs.com A: Because it destroys the flow of the conversation Q: Why is top-posting bad?

18 years, 2 months

PDP 11/24

by silvercreekvalley＠yahoo.com

I've read quite a few DEC faq's recently, but couldnt find performance spec's on the PDP 11/24. Is this the same as the original 11/23? How would it compare with a 11/34A? From what I can see the 34A was restricted to 256Kwords of RAM, whereas the 11/24 seems to support up to 1Mwords? Thanks Ian. ____________________________________________________________________________________ Looking for last minute shopping deals? Find them fast with Yahoo! Search. http://tools.search.yahoo.com/newsearch/category.php?category=shopping

18 years, 2 months

Need 28VDC 4Amp PS...

by wh.sudbrink＠verizon.net

I'm fixing a PowerMac G4 for my Dad's wife. The original PS is dead. It was a pretty standard ATX supply, the only difference is that it supplies 28VDC at 4 Amps on two extra pins. Rather than spending a lot of money on a new supply (more than $250 from the few sources that will guarantee the PS) or a not insignificant amount on a used PS that could go at any time, I want to put in a new standard ATX supply and "tuck in" a small 28VDC PS to drive the two extra pins. The supply is always on, so I can power it from a pass through on the ATX supply. Does anyone have (or know where to get) a small supply? Thanks, Bill PS: This is sort of on topic because Apple says that this particular G4 is no longer supported and "vintage". No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.19.9/1238 - Release Date: 1/22/2008 8:12 PM

18 years, 2 months

Fwd: Behr-Bonz VIC-20 Multicart available

by aliensrcooluk＠yahoo.co.uk

I know the new cart is modern, but the system it's for is old so I figured this would just about be on topic. Anyway, anyone with a VIC-20 read on... Regards, Andrew B aliensrcooluk at yahoo.co.uk rbernardo at iglou.com wrote: To: acug0447 at yahoogroups.com, auscbm at yahoogroups.com From: rbernardo at iglou.com Date: Sun, 13 Jan 2008 03:49:14 -0500 (EST) Subject: {Anything Commodore Users Group} Behr-Bonz VIC-20 Multicart available Long has been the dream of multiple VIC-20 games on one cartridge. Years ago programmer Ward Shrake envisioned and built himself a cart with dozens of games, all selected by dipswitches. Fast forward to 2008. VIC-20 multicart projects go on. For the past months, two different multicart projects have been in development. First out of the gate into the commercial arena is the Behr-Bonz VIC-20 Multicart. With hardware by Eslapion and a game selection menu system by Viande of Denial, the Behr-Bonz VIC-20 Multicart contains 127 games which originally were on separate carts. The following games are on the Behr-Bonz: AE Aggressor Alien Blitz Amok! arachnoid Artillery Duel Astroblitz Atlantis Attack of the Mutant Camels Avenger Bandits Battlezone Black Hole Buck Rogers: Planet of Zoom Capture the Flag Centipede Choplifter Cloudburst Clowns pour Joystick Clowns pour paddle Computer War Congo Bongo Cosmic Cruncher Cosmic Jailbreak Creepy Corridors Crossfire Cyclon Defender DemonAttack Dig Dug Donkey Kong Dragonfire Final Orbit + Bumper Bash Frogger FROGMAN.PRG Galaxian Garden Wars Gorf Gridrunner IFR (Flight Simulator) In the chips Jawbreaker II Jelly Monsters (clone of Pacman) Jungle Hunt Jupiter Lander KEYQUEST Krazy Antics Lazerzone Lode Runner Lunar Leeper Maze Medieval Joust Miner 2049'er Mobile Attack Mole Attack Money Wars Monster Maze Moon Patrol Mosquito Infestation Motocross Racer Mountain King Ms Pacman Mutant Herd Omega Race Outworld Pac-Man (original) Paratrooper Pharaoh's Curse Pinball Pipes Poker Polaris Pole Position Predator Princess and Frog Protector Q-Bert Radar Rat Race Raid on Fort Knox Rally-X Rat Hotel Renaissance (Othello) River Rescue Road Race Robot Panic Robotron 2084 Scott Adams: Adventure Land Scott Adams: Mission Impossible Scott Adams: Pirate's Cove Scott Adams: The Count Scott Adams: Voodoo Castle Sargon II Chess Satellite Patrol Scorpion Sea Wolf Seafox Serpentine Shamus Sir Lancelot Skibbereen Skyblazer Space Ric-O-Shay Spider City SPIDERS OF MARS Spike's Peak Spills and Fills Squish'em Star Battle Star Post Star Trek - Strategic Operations Simulator Submarine commander Super Amok Super Slot Super Smash Terraguard The Sky is Falling Threshold Tooth Invaders Topper Trashman Turmoil Tutankham Type Attack Typo Video Vermin Videomania Visible Solar System You can purchase the Behr-Bonz VIC-20 Multicart for $30 US plus $8 shipping to the US (shipping charge the same up to 10 carts). For postal fees to ship to other countries and other questions about the Behr-Bonz, inquire with eslapion(at)videotron.ca Paypal to eslapion(at)videotron.ca Other ROMs and services are available from Eslapion, too; just ask. I'm getting my Behr-Bonz VIC-20 Multicart right away! Truly, Robert Bernardo Fresno Commodore User Group http://videocam.net.au/fcug The Other Group of Amigoids http://www.calweb.com/~rabel1/

18 years, 2 months

div by 10 on Z80

by cclist＠sydex.com

On 23 Jan 2008 at 19:16, Brent wrote: > Of course, from a clarity-is-all-important modern software design > perspective, we should all be shot. Naw, not even. "Obscure" is miles of spaghetti code twiddling bits seemingly at random in a word, then finally using a "count the 1 bits" instruction on said word to index into a jump table... > If I were an economist, I would predict that at this rate, in another few > weeks the routine will be down to 1 byte. Good thing for us that you're not an economist--you belong in management. Cheers, Chuck

18 years, 2 months

BTI 8000

by cclist＠sydex.com

> Date: Wed, 23 Jan 2008 10:24:27 -0800 > From: Al Kossow <aek at bitsavers.org> > In Aug, 2004, Jim Battle wrote: > > > Speaking of core memory, I used to work for a company that was still > > shipping core-based systems in 1985, when I first joined them right out > > of college. > > The machine was the "BTI 8000", made by BTI Computer > Systems, based in > Sunnyvale, CA. I worked there for only a year, but I > have some > recollection of the machine. > > > I turned up a brochure and technical summary last night, scans up under > http://bitsavers.org/pdf/bti Holy cow--3.5 years to respond to a message! I'm not certain, but I think I may have a boot disk for the 8000, should anyone run into the real thing. Cheers, Chuck

18 years, 2 months

Need 28VDC 4Amp PS...

by cclist＠sydex.com

> Date: Wed, 23 Jan 2008 16:52:23 -0500 > From: "Bill Sudbrink" <wh.sudbrink at verizon.net> Give http://www.jameco.com a shot--they have a bewildering thicket of power supplies in stock. The hardest part is getting through their inventory listing. Cheers, Chuck

18 years, 2 months

Grid MS-DOS 3.3

by cclist＠sydex.com

If anyone else needs MS-DOS 3.3 for the Grid PC, I've put it up at http://www.sydex.com/temp/griddos.zip. Two self-extracting 720K diskette image files and Grid PCMASTER and PCSLAVE data transfer programs. Note that this version of MS-DOS includes enhancements for the Grid PC. I'll leave it up until Friday. Cheers, Chuck

18 years, 2 months

My reply - Re: OLD Computer Magazines to go

by FJGJR1＠aol.com

Dave, Thanks for replying to my other email. I am preparing a detailed reply, but have been busy with some other high priority projects. Overall, you seem to be the best source for and to send to such magazines! I am developing a list of sites related to Kaypros and other older computers I have found and will post it on several websites when I get it done. Those are areas to explore, but you probably know of most of them already. Some of these sites may be good candidates for such magazines. It is a shame all this cannot be saved by someone or some organization, but you just cannot save everything. Once they are gone, you cannot get them back. All the best! Frank **************Start the year off right. Easy ways to stay in shape. http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489

18 years, 2 months

Dead IBM PC 5150

by cclist＠sydex.com

On Tuesday 22 January 2008 22:53:42 Chris M wrote: > what examples could you give as a not so conventional > 8088 board? The console control in the Ruffatti pipe organ at St. Mary's Cathedral in San Francisco? (I don't recall exactly--could be an 8086). Cheers, Chuck

18 years, 2 months

Subject: Re: div by 10 on Z80 was RE: Reading Polymorphic

by cclist＠sydex.com

> Date: Mon, 21 Jan 2008 18:30:10 -0800 > From: dwight elvey <dkelvey at hotmail.com> > I think the restore operation will cause a carry meaning I need > to clear it here with something like: > > ora a ; or other carry clearing instruction I don't think so--let's consider a simple case, using 8 bits and -10. -10 = 0xf6 Our code looks like: add -10 to dividend skip next instruction if carryout subtract -10 from divident The question is "what is the value of the carry bit here?" Let's try some sample values. 0 + 0xF6 = 0xF6, no carry, subtract 0xF6 = 0, no carry/borrow 9 + 0xF6 = 0xFF, no carry, subtract 0xF6 = 9, no carry/borrow 10 + 0xF6 = 0x00, carry; skip the subtract 11 + 0xF6 = 0x01, carry; skip the subtract So the "ora a" to clear the carry shouldn't be required. Saves a few more cycles. For those porting this method to other platforms, be aware that the 6502/PIC subtract works differently than the x80; the carry bit represents "not borrow" instead of "borrow". The same algorithm can be implemented nearly as efficiently on the 8085 by using the "undocumented" instructions, as it includes a double-precision subtract (as well as a 16-bit arithmetic right shift) as a 1-byte instruction. Note that the BC pair must be used in place of DE to use this instruction. It might be possible to implement the algorithm efficiently on the 8080 by letting BC = -DE and using an ADD HL,BC instead of a SBC HL,DE. One is left without a loop counter register however--but then one could "prime" the A register with a 1 and iterate until the 1 migrates to the sign bit of A, then mask it out as part of the exit code. Cheers, Chuck

18 years, 2 months

the PAL

by chrism3667＠yahoo.com

16L8ACN. This is the PAL aboard the Acculogic sIDE-1/16 XT-IDE controller I mentioned. Someone asked :) ____________________________________________________________________________________ Never miss a thing. Make Yahoo your home page. http://www.yahoo.com/r/hs

18 years, 2 months

Dead IBM PC 5150 motherboard - help troubleshooting

by daviderhart＠oldzonian.com

> >You should indeed have activity on the address lines, take another look as the >machine comes up, they should be toggling, even briefly. Could be that data >lines are stuck, and/or it is getting a halt somewhere. Another trick would >be connect a 1k to +5, and touch it to the reset line, you should see the >address lines blip a little then. If they never change state the processor is >dead or the mux buffers stuck (74245's?) . > >If you can build a little proto board to plug into the processor socket so you >can disconnect the address lines from the board, you should be able to 'free >run' the processor, and see activity. If those address lines dont toggle with >clock, power applied and reset low, I would suspect the processor. > >Randy > > >> Date: Tue, 22 Jan 2008 19:26:49 -0800 >> From: jwstephens at msm.umr.edu >> To: >> Subject: Re: Dead IBM PC 5150 motherboard - help troubleshooting >> >> Richard Beaudry wrote: >> > <snip> >> > 6) One thing that seems odd is that the ADxx (Address/Data) lines seem >> > "stuck". The scope does not show a waveform, and measuring with a meter >> > shows some lines right at +5VDC, some at about +4VDC and some at 0VDC. >> > Perhaps the processor is indeed HALTed??? >> > >> On several of the CPU's if you hold the processor reset, you actually >> get the reset vector address out. So on the 8088 8086 80186, you get >> FFF0 out. I don't know if 8088 has all 16 lines out, or is multiplexed, >> but on the 186 we could troubleshoot a board we had with a 186 on it for >> a support processor by setting a flipflop that held it reset, and then >> look at the lines with a scope. >> >> Jim > I did some troubleshooting of some of my 5150's using the "Sam's IBM PC Troubleshooting and Repair Guide Book". I noticed that there is one on eBay right now, item #190193033366. Might help. david.

18 years, 2 months

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test-drb