test-drb

test-drb@ccmp.vtda.org

101090 discussions

by rigdonj＠intellistar.net

At 10:18 AM 4/14/99 -0700, Sellamou wrote: >I don't know about Australia, but here in the States the 9121 drives are >fairly common at ham fests and surplus shops. Someone may correct me but >I believe this is the type of drive that will work with the HP150. Yes, that's correct. Some will work with the double sided 9122 drives also. It depends on which ROMs they have. Joe

26 years, 8 months

Pink Screen of Death? (was: Re: Hallelujah!)

by cisin＠xenosoft.com

> > But what kind of computer would a satellite software company have been > > planning to run that program on before they ported it to the real world? > Hal ?? I can imagine some nutty fanatical CS prof (like me) saying, "If you want TRUE platform independence, then IGNORE all realities of the computer; write your program for an imaginary computer that would be perfect for your needs; then map the keyboard, etc. over to the layout that is present on the real world computer." Is that the way that it happened? Or was there some computer that actually HAD those goofy keys? (There were eventually some aftermarket add-on keyboards for the PC for WordPervert.) Please do NOT interpret this as a defence for MSWeird!

26 years, 8 months

IBM Programmed Symbols Adapter

by Philip.Belben＠pgen.com

>> I just picked up an IBM 3270 Personal Computer Programmed Symbols Adapter >> card in the box. The box says that it's "an option that provides the >> storage and controls for displaying an APL font and six additional >> programmable fonts." It's a full length 8 bit card with two sockets on the >> to edge. There is also two jumpers in the box that I assume are used to >> jumper this card to another card. I didn't get any instructions or >> software with it. Does anyone know how to use it or have instructions etc >> for it? >> >> Joe >> > That sounds like a card which could enable my otherwise useless IBM > monitor meant for the 3270XT. There was a previous discussion on this > machine a while back. I think there were something like 5 cards in the > total array which didn't leave much for peripherals in the XT. On the > other hand I might be thinking of the Epson QX-10 Valdocs :^)) Like Sam, I think of three cards in this connection, but I also recall that not all machines had all cards. The 3270 card may not have been the same card as the display adaptor... On the display side, there was a display card, which may or may not have been part of the terminal card. Without it, you can't drive the 5272 monitor, I'm afraid. In addition, you could get the All Points Addressable (APA) card, which emulated the CGA graphics modes (but note that the 5272 only displays 8 colours), and the PS card, which you have, which emulated the graphics and programmable character set modes of the 3279 terminal. I'm afraid the card on its own won't be of much use... Philip.

26 years, 8 months

More odd things: HP150

by karlm＠blitzen.canberra.edu.au

Today I dusted off the HP150 I picked up the other week, when I saw it I actually believed it was only a terminal, but it had a HP-IB interface which made me pick it up. Discovering that it is a non-IBM compatable 8088 based machine with a touch-screen was nice :-) Not having any drives with it renders it useless as a computer, but I am interested in getting it working as a touch screen terminal, does anyone have the docs for this? or be able to tell me what "Power-on error 1000" means? and how to test out the touchscreen? Megan: I haven't forgotton about the VSV-11, I have holidays next week so I'll fire it up and see if it still works for you, been a busy fortnight :-) Cheers Karl ------------------------------------------------------------------------------ Karl Maftoum Computer Engineering student at the University of Canberra, Australia Email: k.maftoum(a)student.canberra.edu.au

26 years, 8 months

stepping machanism of Apple Disk ][ drive (was Re: Heatkit 51 /4

by Philip.Belben＠pgen.com

>> > Then there was the Tektronix 'almost 6800' used in the 4052, etc. It was >> > a board of 2901's, etc and ran an instruction set that was almost upwards >> > compatible with the 6800 used in the 4051 (IIRC the DAA instruction was >> >> The moto 6800 was protoed using 2901s. It would only need two. > > The Tektronix used 4 2901's and was actually a 16 bit processor (for > address calculations, etc). Just that user data was only calculated using > 2 of the chips ;-) Hey, Tony, why the winking smiley? That's no joke, it's really true! Four 2901s and a lovely 16bit architecture, and then they go and implement a 6800 on it. :-( :-( :-( Philip.

26 years, 8 months

What if,... early PCs (was: stepping machanism

by Philip.Belben＠pgen.com

> RS is colloquial for "Rat Sh-t" in Oz, They don't market under that name > here, but as Tandy or Micronta. > (Accurate product description though isn't it?) :-) In the UK they are also generally known as Tandy. RS is a big company (originally Radio Spares) selling electronic components to the trade. Philip.

26 years, 8 months

VERY OT: Win'98 splash screen

by roblwill＠usaor.net

Me, too, but you don't know my dad... He has his computer in the living room, with the screen facing the window, and he says that he wants it to look nice when it's booting (don't_ask)... I think he deleted the spare one, too. I did a search, and can't find it anywhere. Either the computer didn't come with a copy of the CD on the HD, or my dad deleted the copy, because I can't find that, either. I told him he'd be better off to just put DOS back on the thing.... -- -Jason Willgruber (roblwill(a)usaor.net) ICQ#: 1730318 <http://members.tripod.com/general_1> -----Original Message----- From: Paul Braun <nerdware(a)laidbak.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Tuesday, April 13, 1999 5:26 PM Subject: Re: VERY OT: Win'98 splash screen I'd be thankful. Most people, myself included, use TweakUI to make it go away.... Paul Braun NerdWare -- The History of the PC and the Nerds who brought it to you. nerdware(a)laidbak.com www.laidbak.com/nerdware

26 years, 8 months

OT: VAX 4000/300

by CLASSICCMP＠trailing-edge.com

>Hello. This 4000/300 has been dominating my computer room for a while, >and I love how it looks, but it'd be great if it worked. > >The boot-diagnostic LED on the inside panel is stuck at 'F'. I don't have a >field service manual, so I don't know the exact meaning. I've checked all >of the boards inside to make sure they're snug inside, but no luck. Nothing >shows up on a terminal hooked up to the MMJ jack. The drives seem to >power up. This means that the DC OK signal on the backplane isn't being asserted. If the Q-bus consists of more than one box chained together, this typically means that at least one of the boxes' power supplies either isn't working or has a sick DC OK signal. -- Tim Shoppa Email: shoppa(a)trailing-edge.com Trailing Edge Technology WWW: http://www.trailing-edge.com/ 7328 Bradley Blvd Voice: 301-767-5917 Bethesda, MD, USA 20817 Fax: 301-767-5927

26 years, 8 months

Description of 11/44 Installed Board Set

by hhacker＠home.com

Mitch: Don't know if I have a printset. I will look into that question. Zane: The comment on storage capacity was intended to come across as sarcastic. Also, as a comment on the size of hard disk drives now being sold. I mean, I saw a 20GB IBM (I believe) for under $350.00US at Fry's last week. William R. Buckey

26 years, 8 months

Pink Screen of Death? (was: Re: Hallelujah!)

by fpp＠concentric.net

> Well, I don't know. However, MS Word/Windows and /Macintosh has a strange > option: to have large white letters on a blue background instead of black > on white. This has nothing to do with any color settings, and no other > colors can be used in a similar way. This may have classic reasons. Anyone > know? >Don't know the exact reason but that was the default color >combination of the DOS version of MS Word (and every day I use >the current version, I long for the old one). Well perhaps it is because the de-facto standard DOS wordprocessor was Word Perfect. Their system was default blue screen and white letters. A long long time ago in a system far far away Microsoft was just another software company and they 'adopted' WordPerfect's colors and emulated WP commands. Paul

26 years, 8 months

Computer Storage

by Philip.Belben＠powertech.co.uk

Dear All I am thinking of renting a building in which to store my computer collection, together with that of a friend who has gone to Canada [Bob Manners, for P850UG people]. The building is very simply constructed - single brick walls and sheet asbestos roof - and currently has no supply of electricity or gas, but appears fairly dry (at least at present). Do people on either of the two lists have suggestions for: What precautions should I take in storing computers here? Do I need to insulate / heat the building? Should I install a dehumidifier (I think I can get hold of one)? Do I need (for example) to wrap each computer up in plastic with a packet of silica gel? The rent is very cheap - L2 (about $3.30) per square foot per year, and the building is only 10 min walk from my house. With luck, this will mean that I shall soon have a house with room for me as well as my junk... Philip. <><><><><><><><><><><><><><> Philip Belben <><><><><><><><><><><><><><> Bloedem Volke unverstaendlich treiben wir des Lebens Spiel. Grade das, was unabwendlich fruchtet unserm Spott als Ziel. Magst es Kinder-Rache nennen an des Daseins tiefem Ernst; Wirst das Leben besser kennen, wenn du uns verstehen lernst. Poem by Christian Morgenstern - Message by Philip.Belben(a)powertech.co.uk ********************************************************************** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept by MIMEsweeper for the presence of computer viruses. **********************************************************************

26 years, 8 months

Compupro and DG question

by rigdonj＠intellistar.net

Went scrounging again today. Picked up some good HP stuff. Also found a Compupro 8/16 chassis with no cards or top cover. Also found a Compupro Hard Drive Subsystem chassis. It had one 5 1/4" and one 8" floppy drive. The hard drive and top cover were gone. Is the 8/16 an S-100 chassis? Anyone need this stuff bad enough to pay shipping and a scalper's price for it? Also found a DG hard drive. Looks like a 14" in a clear cover. I think the model number was 3462. Looks too heavy to ship unless someone REALLY wants it. Joe

26 years, 8 months

stepping machanism of Apple Disk ][ drive (was Re: Heatkit 51/4 floppies)

by edick＠idcomm.com

I knew somebody woudl come up with a good example. That 6809 code is probably the closest thing I've seen in a micro. The 8051 uses a similar approach, pointing to the table with the datapointer and uses the accumulator as an offset. It does make it a bit awkward passing a parameter in the accumulator, though. In this case, the accumulator is occupied by what's really the only value you'd want to pass anyway under the circumstances. They (DEC) did make the uVax-II as a chipset for interfacing to their BI-bus, I believe, so that might qualify as well. The DEC chipset probably didn't sell for what a 6809 costs, even the faster part, and certainly not the $0.86 I last saw on the 4MHz Rockwell 65C02. The 6502 and its scions save a clock tick every time they loaded an address because the indexing or whatever arithmetic could be done on the low byte while the high byte was being fetched, leaving the carry set or cleared as was required, for the arithmetic on the next byte as was appropriate. Note that the carry was generally irrelevant, as most instructions requiring indexing simply wrapped the PC, but not in all cases. I thing indexed mode addressing was a case where an index could cross a page boundary. The MOT processors could often do the same thing, but they needed to add a clock tick to order the bytes and another to propagate the carry if appropriate (I think). It wasn't that sort of hair-splitting I was after, but rather, a contrast between the simple, elegant instruction set of one processor, versus the not-so elegant instruction set of "the other" meaning the intel/zilog clan. I'm not surprised that it was in the 6809 that this instruction came up. The 6809 showed lots of promise at first, but once it was in hand, one clearly could see that it would be MUCH easier going with the MC68008 if one had to use an 8-bit bus. I never had the opportunity to write in a high-level language for the 6809, but I was told it should have been quite easy to write a high-quality efficient compiler for it because of its repertioire of instructions and addressing modes. I turned out literally tens of thousands of lines of assembler code for it and never used this feature, though. It's likely most of my code would have run on a 6802 or 6803 just as easily. Dick -----Original Message----- From: Sean 'Captain Napalm' Conner <spc(a)armigeron.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, April 10, 1999 1:27 PM Subject: Re: stepping machanism of Apple Disk ][ drive (was Re: Heatkit 51/4 floppies) >It was thus said that the Great Richard Erlacher once stated: >> >> At the risk of becoming the resident infidel . . . >> >> The 6502, particularly in its later incarnation by Rockwell embodied the >> cleverness fostered by its earlier versions and the non-Intel family of >> processors. How the elegance of their instruction set became lost is a >> mystery to me. > > I've never been a real fan of the 6502, it seemingly geared more towards >embedded systems than for a general purpose computer. But that's just me >8-) > >> On a 65C02 from Rockwell (making the distinction because there were several >> CMOS 6502's, all slightly different) you load the input value into an index >> register and then jump, indexed indirect, to the routine which is >> appropriate for that pattern of inputs. This requires, then, that you have >> a table with 256 bytes, more correctly 128 words, with each word the >> address of the routine which is used to process the left-justified ASCII >> data. >> >> This is tremendously fast! It requires no STACK, and it requires only two >> instructions. Another way of doing this involves building a stack frame and >> loading the return address with a value looked up in a table, then executing >> a return. This can be done with any number of processors. On a Z-80 you >> can jmp HL, and I'm sure there are other neat ways of doing this simple >> thing. I've never seen anything more elegant than that simplistic sequence >> on the 65C02. How the MOTOROLA people let this go by the wayside in the >> design of their 6809, 6801, 68K family, and countless others puzzles me. >> I've not made an extensive study of other processors, but I have looked at a >> few. The only processor I've used which has a similar mechanism at its >> disposal is the 8051 core. It has a data register which can be used as an >> offset for a jump instruction. > > If I understand the problem correctly, then what you want can be done on >the 6809 as two instructions as well (okay, three, but the first one is only >there for setup): > > LDX #JMPTAB > MAIN: LDA UART > JMP [A,X] > > > As long as X is unchanged, your overhead is two instructions. Also, if >you want to use X for something else, you still have Y or U for use as well >(okay, you can use S, but then it gets a bit harder 8-) > > But if you want elegance, go with the VAX---one statement: > > caseb uart,0,255 > jmptab: .word c00 - jmptab > .word c01 - jmptab > > ; ... > > .word cff - jmptab > > And with this, you don't even have to jury rig a special UART. > > In fact, the VAX is about as elegant as they come---you have 16 general >purpose registers and the PC is one of them (R15). Not only that, but all >addressing modes work on all instructions---it's very regular and with some >practice you can probably end up reading hex dumps directly. It's a very >nice assembly language. > >> Now, I doubt that anything that simple can be used to discriminate between >> what's "best" and what's not, but it's for certain that it's a nice feature >> not available on the 6809. I used the 6809 extensively while I was in the >> aerospace industry, and found it fairly friendly. BUT, it still is >> relatively slow, as compared with processors of the same generation from >> sources clever enough to arrange the bytes the other way around in memory so >> you didn't have to fetch and the discard a high byte when there wasn't one. >> Fortunately, many tasks don't require a really fast processor. > > I don't follow. You either care about a 16-bit quantity, or you don't, >but I may be biased---my first CPU was a 6809 and when I switched to the >Intel x86 architecture, I didn't like the little endianess of it at all, but >I never found the bigendianess to be a real problem. > > -spc (Then there's the ARM ... ) > >

26 years, 8 months

Big Iron

by mbg＠world.std.com

I've got the pictures of the KS10 systems up on my web page... For anyone interested... http://world.std.com/~mbg/home_systems.html#ks10s to read a little about it.... Megan Gentry Former RT-11 Developer +--------------------------------+-------------------------------------+ | Megan Gentry, EMT/B, PP-ASEL | Internet (work): gentry!zk3.dec.com | | Unix Support Engineering Group | (home): mbg!world.std.com | | Compaq Computer Corporation | addresses need '@' in place of '!' | | 110 Spitbrook Rd. ZK03-2/T43 | URL: http://world.std.com/~mbg/ | | Nashua, NH 03062 | "pdp-11 programmer - some assembler | | (603) 884 1055 | required." - mbg | +--------------------------------+-------------------------------------+

26 years, 8 months

DG AViion stuff

by geoffrob＠stmarks.pp.catholic.edu.au

Someone wanted stuff for the M88K Data General Aviion's running DGUX. There is a fair bit at this site.. http://ftp.avlib.clemson.edu/avlib/pub/88k/ Hope this helps Cheers Geoff Roberts Computer Systems Manager Saint Mark's College Port Pirie, South Australia. Email: geoffrob(a)stmarks.pp.catholic.edu.au ICQ #: 1970476 Phone: 61-8-8633-8834 Mobile: 61-411-623-978 Fax: 61-8-8633-0104

26 years, 8 months

Trenton Computer Festivalt

by museum＠techniche.com

Can either of you supply any details? Date? Times? Specific location? >> I'm thinking about attending the upcoming Trenton Computer Festival. >> Unfortunately, if I do go, I won't be able to make it until Sunday. Any >> opinions on whether or not the second day of the TCF is worth a two and a >> half hour drive? >> >> Thanks. >> >> Tom Owad > >In the old days it was bargain and dumpster dive day. >TCF was a lot like what the VCF sounds like. (Except with a mix of some of >the classic stuff with some of the newer computers.) > >PDP 8's, and PDP11's as well as S100 stuff was common. Now there's some >Sun, Vax, HP Unix stuff, some older S100, H89, H8. Some CP/M (rare) >some Macintosh and Apple II/III... But it's becoming more and more >a Windows and PC kind of show. > >I don't know what it'll be like this year with Ken Gordon running the show >on contract (but I fear the worst). > >Bill >--- > bpechter@shell.monmouth.com|pechter@pechter.dyndns.org > Three things never anger: First, the one who runs your DEC, > The one who does Field Service and the one who signs your check. >

26 years, 8 months

TRW Swap & Vintage CompuCrawl(tm)

by jpl15＠netcom.com

A Reminder: Saturday, April 24th.. for all listmembers who will be in the Southern California area - The TRW Ham Radio and Electronics Swap Meet will be heald on the morning of the 24th, from 7:30 to 11:30, in the southernmost parking lots of the TRW plant in El Segundo, CA. From the 405 (San Diego) Freeway, take the Rosecrans exit west, go west on Rosecrans about 1 mile to the intersection of Aviation, then left at Aviation (under the Metrolink bridge)... proceed south on Aviation 1/2 mile, the swapmeet will be in the parking lots on the right, before Marine avenue. After the swapmeet, there will be the customary CoCo's Brunch 'n Brag, from noonish until one-ish. THEN: I will host a Vintage Computer Open House CompuCrawl. Listmembers and interested persons are invited to my place to look at / play with / make scurrilous jokes about my motley collection. I have four DEC machines running and a Pr1me 2550, as well as various micros, etc. This event will last until whenever Saturday night. Persons needing advance directions to my residence are encouraged to e-mail for directions. I *do* live in a rural area so directions are recomended. I believe some persons from outside the SoCal area expressed interest in showing up, so e-mail me privately for contact info. Cheerz John

26 years, 8 months

Sigh. Bringing up a PDP-8/M

by allisonp＠world.std.com

<OK... First thing is to clean out the backplane in the 8/m. Use a vacuum <cleaner to remove loose dust and then squirt isopropyl alcohol <(propan-2-ol) into the connectors. Dry it well before powering it up. Also make sure there are no shorts under the backplane to the outer case from foreign objest like screws. <Then, if it still doesn't halt, check the power supply. I can't remember <what the power good line will make the CPU do if it's in the wrong state, <but I don't think it forces the CPU to the RUN state (unlike the 11/45...) It does have power fail and if it's in the "wrong" state the machine it halted. Look for obvious stuff, shorted wires or other conductors (even on boards) and leads floating loose or misconnected. CHECK all three voltages because if any are missing it will do nothing intelligible. Allison

26 years, 8 months

VERY OT: Win'98 splash screen

by fpp＠concentric.net

>Me, too, but you don't know my dad... >He has his computer in the living room, with the screen facing the window, >and he says that he wants it to look nice when it's booting (don't_ask)... >I think he deleted the spare one, too. I did a search, and can't find it >anywhere. Either the computer didn't come with a copy of the CD on the HD, >or my dad deleted the copy, because I can't find that, either. >I told him he'd be better off to just put DOS back on the thing.... If he did not get the Windows CD then perhaps you have a bootleg copy of Windows. All new PC's have a CD copy and Microsoft certificate of authenticity.

26 years, 8 months

Restoration of an 11/34a

by mbg＠world.std.com

>You did remember to cut the NPG jumper on the slot that you stuck the >RL11 in, I hope... Thanks... I did forget (I've done mostly Qbus for quite awhile... so the UNIBUS specific stuff may slip my mind for a bit) >That's the most common 11/34 problem, assuming you're using an M9302 >terminator. You have a grant open somewhere (either you're missing an >continuity card or you've got an NPG jumper missing). THe M9302 then >asserts SACK, the CPU tries to remove the asserted grant line but can't, >and it locks up. Aha... right... I'll have to check the backplane... there were a number of boards in it, some were probably DMA devices... (as I said, it may take a little time for it to come back to me...) Megan Gentry Former RT-11 Developer +--------------------------------+-------------------------------------+ | Megan Gentry, EMT/B, PP-ASEL | Internet (work): gentry!zk3.dec.com | | Unix Support Engineering Group | (home): mbg!world.std.com | | Compaq Computer Corporation | addresses need '@' in place of '!' | | 110 Spitbrook Rd. ZK03-2/T43 | URL: http://world.std.com/~mbg/ | | Nashua, NH 03062 | "pdp-11 programmer - some assembler | | (603) 884 1055 | required." - mbg | +--------------------------------+-------------------------------------+

26 years, 8 months

CLASSICCMP digest 734

by mtapley＠swri.edu

>From: Dwight Elvey <elvey(a)hal.com> ... > There were several Forth machines done over the years, ... >Harris made one that was used quite >often for space applications because it was fast >and could run with smaller amounts of code ( a feature >of Forth ). Still makes, the RTX2010. The IMAGE mission that I'm working on will have three of them aboard, running 3 of the 6 instruments, when it lifts off in early 2000. - Mark

26 years, 8 months

WTB: TRIMM DA523-331

by jhfine＠idirect.com

I am not positive if this is the correct part number. Have you ever seen a PDP-11/34 top loading rack mounted box? About the same size! Also top loading. About 10 1/4" high and a 19" rack. BUT, this is for a Qbus back plane with at least 10 slots (there could be as many as 16). And I suspect that the first 3 slots may be ABCD like the BA23 box and the rest are AB/AB also like the BA23 box. Sincerely yours, Jerome Fine

26 years, 8 months

Computer Storage

by allisonp＠world.std.com

<What precautions should I take in storing computers here? < <Do I need to insulate / heat the building? Within bounds no. Most componenets will take 0-50C as commercial temperture range. Sharp changes in temperature are not beneficial so if cold leave it that way, if warm don't shock cool it. If you can stay within 10-40C there should be no problem. Electrolytic capacitors however, dry out of kept too hot for too long. <Should I install a dehumidifier (I think I can get hold of one)? Moisture is the enemy during the seasons where you get the greatest cyclic temperature changes. And most winters. <Do I need (for example) to wrap each computer up in plastic with a packet o <silica gel? If it's a sealed bag aroung the equipment, that works very well. the bag has to be sealed or the silica will saturate quickly. the silica can be dried in a warm oven to drive out the moisture and render it effective again. Also the package (system, box, rack) should be made vermin proof as insects can leave deposits and rodents can chew, nest or soil things. Allison

26 years, 8 months

Commodore vs Apple [WAS: Re: stepping machanism of Apple Disk

by allisonp＠world.std.com

<This must have varied significantly with geography. In Ontario, Canada, <where I grew up, Commodore was king, both at home and in schools. Most <schools' first computers were PETs, either alone or in clusters, followed I'd say so. I'd see one school district with TRS80 and the next one over apples or commies. Made teachers nuts. Allison

26 years, 8 months

z80 timing... 6502 timing

by allisonp＠world.std.com

<the relatively short memory access strobe, while I was talking about the <frequency at which they occur, as defined in the spec. I agree completely Yes so? Often the z80 is moving 16bits, with 8bit wide memory it's going to take several cycles. If it were a z280 that would be even more biased as it uses fewer "ticks" per cycle and the bus is 16bits wide. Counting ticks or whatever as I've repeatedly stated meaningless save for discussions of how memory is used and not who is faster. An aside at this point, the z280 runs different cycle timing as @4mhz would be the base z80 of the same speed and the z380 (in z80 native mode) beats that as the cycles have been shortend again. <personal. The fact remains, that the memory CYCLE is three clock ticks <long, as defined in the spec (though I haven't looked at it in 15 years or It is not and Like I said the spec is infront of me as I type. Worst case its 2. But that in itself is again meaningless. <so since I haven't yet unearthed my Zilog or Mostek data books) and if you <look at the pictures you saw with your logic analyzer, you should have see <two read pulses of whatever lenght they were, spaced at very nearly 750 ns <each time you saw the execution of an absolute jump, or any other <instruction which consists of an opcode followed by a 16-bit address. The <same is true of writes. They take one memory cycle, which is three clock <ticks long, for each byte, although the memory write strobe is a mite <shorter than the read strobe, IIRC, which I might not, but . . . Your memory is faulty. and that 750ns bumber is still meaningless. they only number for comparative purposes is the amount of time it takes to do an absolute jump. For Z80 @4mhz that will be 2.5us. It will require memory in the 250ns range to do it. <were inserted as they often were for M1 cycles. Nevertheless, commonly use <instructions were MUCH faster on the 2 MHz 6502, than on the 4 MHz Z-80. A 2mhz 6502 executes a 1byte (say INX) instuction in 2 machine cycles and that takes 1uS. A 4mhz INC B (any register) takes 4 z80 clocks at 4mhz... damm if that doesn't happen to be 1uS! Where is the speed difference? According to my book a 6502 absolute jump takes 3-5 cycles and in the 5 cycle case its 2.5 us. <probably measure three microseconds for those twelve clock ticks (T-states <which is EXACTLY how long a 1 MHz 6502 takes to do that. Hence, I conclud Exactly my point. The 6502 is not faster, it only marches to a different drummer. <I've concluded that most code I've seen underutilizes the internal resource <and overutilizes the external ones. Code like that favors processors with <more time-efficient use of the external resources. Hence, my assertion tha <there's reason to believe the 6502 at 2 MHz could outrun the 4 MHz Z-80 in <more or less typical code and in a more or less typical hardware No again. It can match the z80 and in some cases it's better or worse. <environment. Code written to make better than average utilization of the <internals of a Z-80 might fare better against equally well-written code on <6502. I'm comfortable with the reality that I'll probably never know for <certain. Since neither processor is particularly important these days, no <terribly important to me either. Agreed well written code is essential for either to do useful work. <None of this is really worth getting all excited about because, by the way <in spite of its "better" performance, (by my assessment) the 6502 didn't <accomplish more useful work on MY behalf, because I used a Z-80 running CP/ <every chance I got due to the abundance of really decent tools and office <automation software. Therein lies the key. A good system is not always defined by it's hardware. Systems are a combination of practical hardware and functional software. This account for why despite their flaws the TRS80, Apple II, Z80 CPM based as well as others florished. Most people didn't program 8080z806502ti990018028085680980886800065815 they ran basic or a word processor. the run on of part numbers was deliberate as to most people the cpu used was just a number. Allison

26 years, 8 months

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test-drb