test-drb June 2000

test-drb@ccmp.vtda.org

160 participants
580 discussions

by allisonp＠world.std.com

>of "better" that you use. I've recently been fiddling with techniques for >taking what was, back in 1982, considered a pretty good implementation of >the general case of Z80 application, e.g. the Ferguson Big Board, which used >the standard Z80, and NOT the Z80-A which ran at 4 MHz instead of the >standard Z80's 2.5 MHz. I've got a number of these boards so I can test the In 1982 that was a low end example. DECs VT180 was a 4 serial port, 4mhz, no wait states With DD floppy design. It was ment to go in a VT100 so video was not needed. My NS* S100 crate in 1978 was running at 4mhz even. In the z80 world there were those that used Z80 peripherals and live with the limits they imposed and those that went with other parts. What was the limits? Price, they were not cheap and they were SLOW. By 1982 a Z80 not running at at least 4mhz was considered slow and by 1983 that would be 6mhz. Parts existed to do that. >in place of potentially better chips because they did make the design dirt >simple and the supported some features that other devices didn't support, >e.g. Z80 mode-2 interrupts. Mode 2 was supportable without Z80 parts, easy and cheap to do. >the Ferguson BigBoard, i.e four parallel ports four serial ports, local >video and using a parallel keyboard rather than a terminal, using a single >device, i.e. an FPGA or CPLD (take your pick)and one memory IC. When you're >done, you 'll have a CPU that operates at about 25 MHz, a double/single >density FDC, the parallel and serial capabilities and other features of the >Ferguson board. I don't know whether the result will be better. Try a Z180 part at 33mhz, SCC or other all on one chip like the SMC92667 and static ram on a 3x4" board. Takes very little glue to do that. The question goes mroe to price and creative engineering. Allison

24 years, 6 months

Building a better "old" computer

by allisonp＠world.std.com

>Based on what the current computer industry knows about building computers, >would it be possible to build a better Z80 based computer today, using the >same chips that the builders in, say, 1979 had available? Yes. Though finding the parts would be hard. >I heard someone say that the manufacturers did the best they could with what >they had to work with "back then," and I started to wonder if we could do it >better today. Has our understanding of how it all works improved enough to >do it better now, using the same chips, etc.? For pre micro processor... there were designs that did thig with transistors and later SSI that were way ahead of the pack so the answer was yes and no also. For the z80 case: Yes and no. Some designs the designer was doing the best they could though the parts were more capable. Many cases the goal was to meet a price so that limits you. There were some very capable designs. But, using the same parts you could have done better then assuming the budget (size, power, $$$$) allowed it. Can you do better now using current parts and reusing old z80s, yes. Allison

24 years, 6 months

RA81 problem :(

by peter＠joules0.demon.co.uk

I haven't used my MicroVAX II in some time, and one of it's RA81s wont spin up. It starts to spin, for about 1 second, and then cuts out and, after pressing the 'fault button' it leaves the fault light on and the 'B' light flashing. According to the RA81 user manual the cause is 'spin error' (I could probably have told _them_ that ;-). Can anyone give me any advice on whether it is possible to resurrect the HDA? If not, I have another drive which has no fans so I can make a good one out of the two but the one which has gone down contains my only copy of VMS. Is it drag in the bearings which is causing it to cut out whilst the motor is accelerating it? If so is it possible to lubricate them without opening up the HDA? -- Regards Pete

24 years, 6 months

DD disks and HD drives (was: Where can I find...)

by allisonp＠world.std.com

Well you left out all the caveats. I do it all the time, no problem. Key thing is while the drives are HD capable (TEAC FD55GFV) I happen to have them jumpered as required to properly run DD mode. In this mode they are plain DD, DS 96 TP! drives. Allison -----Original Message----- From: R. D. Davis <rdd(a)smart.net> To: classiccmp(a)classiccmp.org <classiccmp(a)classiccmp.org> Date: Saturday, June 24, 2000 11:06 PM Subject: DD disks and HD drives (was: Where can I find...) >On Sat, 24 Jun 2000, Tony Duell wrote: >> DD drives or that DD disks can be used in HD drives _as HD disks_ (most >> HD drives can also handle DD disks, but only to store the amount of data >> that you'd get from a DD drive anyway). > >One word of caution regarding the use of DD disks in HD drives: it's >been my experience that which this may appear to work, problems >sometimes arise when one attempts to read the data written in a DD disk >by an HD drive. It's only reliable as long as you're using the same >drive; on quite a few occasions over the years I've had this happen when >attempting this. So, it's safest to write to DD disks with DD drives, >although this should be readable by any HD drive. > >-- >R. D. Davis >rdd(a)perqlogic.com >http://www.perqlogic.com/rdd >410-744-4900 >

24 years, 6 months

Question about TK50Z-?A

by allisonp＠world.std.com

>I would appreciate some help from anyone who knows >about the difference between a: > >TK50Z-GA and a TK50Z-FA. The long and short of it is nearly none and everything. the are the same mechanically, same boards, same drive same for everything save two things... SCSI address and one does not talk modern SCSI software protocal. IE: the difference is firmware on the SCSI to TK50 board. FYI: one is specifically for MV2000 and the other is useable on many later SCSI systems (other than MV2000). What I've forgotten is which is which. Allison

24 years, 6 months

Where can I find 5.25 DS/DD disks?

by allisonp＠world.std.com

>First, where is the best place to buy some new ones? I don't know, I have enough to keep me going for years. >Second, does any manufacturer still produce this media, and what is the >shelf life? Basically, what I'm asking here is, will our 5.25 drives become >useless before too much longer? Not likely. I have 5.25 media that is 20+ years and still good. It's likely you have things reversed, the drive may fail first. ;) >I remember a discussion on the group a while back regarding the use of HD >media in DD drives. After reading about two thousand messages more >complicated than quantum mechanics, I gave up trying to figure it out :-) >So now I've resigned myself to seek the newest 5.25 DS/DD disks that I can >find. Any help appreciated! Long live my Commodore 128! NO majik, the darker HD media is for 1.2mb use and the ligher brownish media is for all others. the other half is do not use 96tpi drives to *reliabily* write 48tpi media or the reverse (special projects and emergency cases may be a reasonable exception). If all else and it's possible, upgrade the drive used to a 3.5". Some systems can do this easily some can with some programming work, some cannot easily be modded. Above all else keep media in a cool dry place, avoid direct sunlight. Allison

24 years, 6 months

TI-99 power, voice synth

by mrdos＠swbell.net

I think that the original idea behind that compartment was that TI would release vocabulary modules that would fit in there, but I could be wrong. I saw a working TI-99 at a thrift store yesterday. It has a power supply, but I didn't get it because I already have one. I'll see if I can pick it up tomorrow. If so, you can have the power supply. -----Original Message----- From: Marion Bates <Marion.Bates(a)dartmouth.edu> To: classiccmp(a)classiccmp.org <classiccmp(a)classiccmp.org> Date: Saturday, June 24, 2000 2:03 PM Subject: TI-99 power, voice synth Heya, I recently picked up a TI-99/4A at the local thrift store, but couldn't find the power cable. Anyone got a spare or know where I might look online to find one? Also, I found with it the voice synthesis module. Like the Intellivision, it's a pass-through cartridge thing, but there's a flip-up door and some sort of compartment in it -- what the heck is THAT for? Thanks... -- MB

24 years, 6 months

Question about TK50Z-?A

by jhfine＠idirect.com

I would appreciate some help from anyone who knows about the difference between a: TK50Z-GA and a TK50Z-FA. I am able to get a TK50Z-GA working under a SCSI host adapter (CQD-220/TM) on a Qbus system (I set the SCSI ID=4) and I see a standard TK50 tape drive under RT-11. But, I also suspect that the TK50Z-FA is probably broken. Sincerely yours, Jerome Fine

24 years, 6 months

Licenses (was Re: Should I add a "Micro" PDP11/73 to the Herd?)

by allisonp＠world.std.com

>Would that mean that a "shared" (I realize that back in 1988, shared disk >drives were probably not generally available - and if they were would probably >have cost more than extra distributions of the software) disk drive could have >been used at one location connected by "short" cables to many computers? Ah but, they were available, LAPLINK, lantastic and ohers were around. It wasn't cheap but the SHARE.EXE was part of dos 3.3 and later. Compared to the costs of large disks then the price was appealing. >OR as an alternative, it would seem to be very possible to use a server >which had the only disk copy and execute the software on each local >computer by the many students reading the book from different positions >at the same table? Overhead projector? Schools used them. >But aside from such considerations, the general substance of the license >was that Borland, even in 1988, was trusting large companies to have >purchased sufficient copies of the software. PLUS, once purchased, there >was no attempt of any kind to prevent a user from transferring the right to >use the software to a different user on either the same hardware - if the >computer system was sold - OR on even a completely different, but >compatible, computer system so long as the original software was no >longer installed and being used on the first computer system. True but you left out one thing. Their total goal was a Plain Engilsh license. I read the DELPHI-5 (current) and it's understandable. Read some of the MS licences or others and time for an asprin. >For instance, if Microsoft had gained monopoly control of the internet via its >browser and wanted to stop a boycott of its operating systems, all email >urging such a boycott could end up being "lost" for some unexplained "reason". They are close with MSN being a backbone and IE being part of the OS. For some here that may remember. Back when, There was ABC TV, ABC FM radio and even ABC AM radio, all one company and network (same for NBC, CBS). The FCC saw fit to break that up as it represented a monopoly on communications. Yet we have MS (OS, APPS, content and Browser), MSN their network, and so on. Think about it. As to Mentec, a simple low cost non commercial license for what ever OS/Apps they currently own copyright to would be nice. Further a package of media, manuals and license for current (or one back versions) non commercial without support for a reasonable price would be attractive. then again I have no idea of the current price of a copy of RT-11 (Docs, media and commercial license) goes for. Allison

24 years, 6 months

Should I add a "Micro" PDP11/73 to the Herd?

by allisonp＠world.std.com

>Zane replied to Allison: >> Do you have any understanding of the computer industry? Do you have any >> understanding of computers larger than your Windows box? Do you even look >> at the licenses of any software you have purchased? I'm fairly sure you >> don't remember the days when you didn't even own the computer, you rented >> it, or rented time on one. I didn't write that but I essentially agree. Consider this you buy a book, you own it to dispose of how you wish (sell, give or burn). You don't buy a license to read it or X many friends to read it. It is property. The copyright means you can't make copies of it (other than limited amounts for reference with attribution) to sell or give away without expressed permission. Software is going the route of, you pay for the media, manuals and support(optional) and also for rights to use under specified conditions as a CONTRACT. There lies the difference. the manuals are property (usually) but the software is provided under some stipulation (even freeware!) regarding it's use. >vendor, you got the software for FREE from the vendor. Allison correctly >pointed out that before some point these damn software licenses didn't >exist. The idea of XYZ Co OWNING the software (copyrighted) is quite old and may preceed the 1960s! At one time computers were only rented. DEC was one of the first to alter that by selling machines outright. Allison

24 years, 6 months

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test-drb June 2000