test-drb November 2010

test-drb@ccmp.vtda.org

162 participants
241 discussions

by lynchaj＠yahoo.com

SCSI to IDE joe lobocki jlobocki <mailto:cctalk%40classiccmp.org?Subject=Re%3A%20SCSI%20to%20IDE&In-Reply-To= %3CAANLkTinO5OZGqmp_tiokWNnqYD_e7AAwKDE7ALoG2_8%2B%40mail.gmail.com%3E> at gmail.com Fri Nov 26 10:48:01 CST 2010 * Previous message: AT <http://classiccmp.org/pipermail/cctalk/2010-November/294377.html> &T 3B1 Unix PC Boot ROMs * Next message: SCSI to IDE <http://classiccmp.org/pipermail/cctalk/2010-November/294385.html> * Messages sorted by: [ date ] <http://classiccmp.org/pipermail/cctalk/2010-November/date.html#294382> [ thread ] <http://classiccmp.org/pipermail/cctalk/2010-November/thread.html#294382> [ <http://classiccmp.org/pipermail/cctalk/2010-November/subject.html#294382> subject ] [ author ] <http://classiccmp.org/pipermail/cctalk/2010-November/author.html#294382> _____ Ok, so I have been doing research, and this affects everyone here who collects SGI, apple, and anything using scsi. in the near future, the supply of smaller SCSI drives will eventually dry up, due to failure from age and lack of supply, as I believe they are no longer manufactured, unless for the industrial/server market. I could be wrong on that part, but I take it as such because my searching for them brings up nothing new. what does that mean for collectors? it means that your neat little apple or SGI or etc will run, until the scsi disk dies, then we will be left cannibalizing machines for disks, paying ridiculous prices for leftover scsi disks, which will skyrocket because of the small supply. So what is our option? I have seen SCSI to IDE adapters around, but they go up into the $100's to $200's, say you have a minimum 10 machines, that leaves you somewhere between $1,000 and $2,000 total, before the disk or devices. If we could design a simple SCSI to IDE interface, we could be set for a good long while on storage for these devices for a decent amount of time. There are all sorts of adapters to IDE, there is CF to IDE, SD to IDE, SD to CF which could be placed in a CF to IDE adapter if need be, i'm sure one could also rig up a USB drive to SCSI if one tried, but I could be wrong. Having said that, I know nothing about programming microcontrollers or simple processors, but I have seen people on the board who do. I'm sure if we can find a chip capable, and lay out a schematic, source code, and possibly a board layout, members could source their own boards and components to build their own devices at home (given they have a chip programmer), so no one person has to take on the responsibility of supplying parts, kits, finished devices unless they so choose to. This is just an idea, if nothing becomes of it, no big deal, just putting it out there.... -Joe _____ * Previous message: AT <http://classiccmp.org/pipermail/cctalk/2010-November/294377.html> &T 3B1 Unix PC Boot ROMs * Next message: SCSI to IDE <http://classiccmp.org/pipermail/cctalk/2010-November/294385.html> * Messages sorted by: [ date ] <http://classiccmp.org/pipermail/cctalk/2010-November/date.html#294382> [ thread ] <http://classiccmp.org/pipermail/cctalk/2010-November/thread.html#294382> [ <http://classiccmp.org/pipermail/cctalk/2010-November/subject.html#294382> subject ] [ author ] <http://classiccmp.org/pipermail/cctalk/2010-November/author.html#294382> _____ More information <http://www.classiccmp.org/mailman/listinfo/cctalk> about the cctalk mailing list _____ -----REPLY----- Hi! I am willing to make a PCB and offer it as part of the N8VEM home brew computer project. If someone would send me a design I will be glad to make a schematic, PCB layout, and get a small number of prototype boards. This could be a simple circuit comprised of a Z80 with three 8255 PPIs, RAM and ROM (one 8255 for IDE, two 8255s for SCSI-2) or a more complex microcontroller scheme. Please contact me if interested. Thanks and have a nice day! Andrew Lynch

13 years, 5 months

cctalk Digest, Vol 87, Issue 54

by shawn.t.rutledge＠gmail.com

> So what is the Z80 card for? Apparently for running CP/M on a PC. http://books.google.com/books?id=gD4EAAAAMBAJ&pg=PA1 http://books.google.com/books?id=NjAEAAAAMBAJ&pg=PA1 http://pctimeline.info/ibmpc/index.htm 1982 March Xedex introduces the Baby Blue card (a Z80B processor on a plug-in card), allowing the IBM PC to run standard CP/M programs. Price: US$600. [346.92] [396.10] (April [9]) (Vendex company[346.93])

13 years, 5 months

Update on Epoxy Potting Removal

by scanning.cc＠gmail.com

Now that I have access to the main unit the plot thickens. All of the outputs of the potted brick go to full-wave bridge rectifiers in the main unit such that you get a plus and minus voltage reference to the CT ( center tap ). That big potted POS is nothing more than a big friggin transformer ! The main output leads ( 1 2 and 3 ) have 28 VAC coming out of them. I put a Variac on the " transformer " and turned it up very slowly. At not much voltage it gets very HOT ( I suspect shorted windings or a whole shorted primary on the input side. The 28 VAC output figure came from estimating proportionally what the output voltage would be with a full 115 VAC on the input primary. I own this puppy now !! Best regards, Steven

13 years, 5 months

MEK6800D2 restoration

by wim＠hackbox.be

> As somebody elase said, I think you have to read the data regiater too. Ok, I improved my test program to read the data reg and also give some visual feedback: LDAA #$10 ; like in JBUG STAA $8008 ; ACIA control STAA $8022 ; enable 1 digit leds LOOP LDAA #$7F STAA $8020 ; clear display READ LDAA $8008 ; ACIA status ASRA BCC READ ; data ready? LDAB $8009 ; ACIA data STAA $8020 ; display status LDX #$0100 ; delay DELAY DEX BNE DELAY CMPB #'G ; EOT? BNE LOOP SWI The idea is to light a digit for a brief period when a byte is read and have the segments show the status register. Also it should exit if it received the "G". Ok, the G may be *in* a data block but I hardly ever found a G anyway. At least it allows me to tune the volume until I receive something. But it looks random and looking at the leds, like half of the bytes read are framing errors. Obviously, I varied what I could think of (delay, "G", ...) used several recorders (2PCs with audacity, a real cassette deck and two audio cables) > I assume you have the manual for this evaluation kit. It's on bitsavers > if you don't. It explains how the cassette interface circuitry works in > some detail, and is well worth reading. Yes, I have the manual and read it through. > I asusme you intiialising the 6850 correctly, and that you're settign > that 4053 analoge switch properly,. If not, it can never work. I'm initialising it by writing $10 in the control reg, which I copied from the JBUG listing. I don't find any reference of a "4053" or similar in the docs of the kit. > Do you have a (real [1]) tape recorder? If so, try saving something. > Listen to the recording, does it sound like the typical 'burble'? And try > loading it. Point being if there's something wrong with how you're playing > the audio files you could have problems. Yes, dug up my Realistic cassette recorder that came with my TRS-80 but it didn't help. The samples I'm trying to load are recorded with the kit itself. They sound typical and I was able to decode them to binary. As a test, I decoded the jbug rom and compared it to the file from bitsavers. It matched! (except for 4 bytes near the end which are zero on bitsavers an are actually different on my rom). That made me conclude that the 'punch' function is working and the samples I'm using are good. I would like to test with a known-good audio file but I can't find any... I must point out that the kit is expanded and I haven't figured out what it is exactly. The wirewrap area on the processor board has two extra ACIAs and a crystal. I understand the original was a 614.4, this seemed to be replaced by 1MHz and the 614.4 used for the other ACIAs. Anyway, I already swapped them (which did make me type less double characters since I guess the keyboard scan delay is chosen for the original clock speed). The kit came with a Philips Mini-DCR and the cables seem to be made to connect that on the J1 I/O connector. I could go the route of restoring that, but it seems more challenging and it wouldn't allow me to transfer data with the outside world. But I'd like to get at least to the point that I can load and run a program without having to type it in... I also read that the kit allows to connect RS-232, that would be ideal but I don't see how that's possible without adding components and wiring. Wim.

13 years, 5 months

Another Crazy Idea: disc drive controller swapping

by classiccmp＠philpem.me.uk

Here's another idea that'll get me a place in the Loony Bin. A little while ago I picked up a couple of Amstrad EME232 double-sided 3-inch floppy drives. Out of the three I have, two have had their read-write ASIC zapped by someone (in one case myself, in another an ebay seller) plugging them into a PC power supply to "test". Net result: the ASIC goes completely deaf. Let's assume for a minute that the heads in the EME232 drives are undamaged. That means all the issues are related to defective circuitry on the PCB. So, how about this for an idea: move the controller chip and surrounding circuitry (or even the whole board) to the EME232, then wire it into the existing drive mechanics. This would -- in theory -- allow the two dead 232s (and possibly the EME156 single-head drive) to be resurrected. Anyone care to comment on this idea and its possibility or absurdity? The other option would be to get a new read-write ASIC for the Amstrad drives, but those seem to be like hen's teeth. Part number is M51017AP (made by Panasonic but if memory serves they're not marked with a logo or manufacturer designation) if anyone wants to check.. :) Thanks, -- Phil. classiccmp at philpem.me.uk http://www.philpem.me.uk/

13 years, 5 months

NCR stuff on ebay

by wmaddox＠pacbell.net

Mixed in these lots, there appear to be boards and test fixtures for a 16 bit mini of some kind. Anybody recognize this stuff? http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=280592757605 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=280592443576 --Bill

13 years, 5 months

Xedex Z80 ISA card and other stuff on ebay

by shawn.t.rutledge＠gmail.com

The Xedex board is part of this auction: 260696713390 and there is other old PC stuff in my other auctions, digiboards and HUB6 serial boards.

13 years, 5 months

HP computer rescue?

by charlesmorris800＠centurytel.net

There is an HP9845B computer with a large hard drive available for pickup in northern Maine. ***Contact the owner (Terry Helms) directly at: mainehiker at gmail.com; *** Please don't email me, I just told you everything I know about it :) Here is the picture he sent me. http://i1181.photobucket.com/albums/x426/DrCharlesMorris/IMG_4102HP9845Bcom… Hope someone in New England can rescue this interesting looking system. thanks Charles

13 years, 5 months

AViiON and Microdata 1600

by mcguire＠neurotica.com

Well, I've unpacked the AViiON and the Microdata 1600 inside, but it looks like I won't be able to look at them for at least a week or two. My lady and I are leaving in moments for YET ANOTHER trip up north (we've been home for less than a week!) due to someone's passing. I love driving, but enough is enough. My cats will never forgive me. Maybe some new goodies will come my way on this trip like last time. I'll be going up 95, then into West ("By God!") Virginia and staying there for several days, perhaps a week. I'll be driving a mostly-empty car. ;) -Dave -- Dave McGuire Port Charlotte, FL

13 years, 5 months

AT&T 3B1 Unix PC Boot ROMs

by classiccmp＠philpem.me.uk

Hi guys, Here's a treat for the 3B1 owners in the audience: images of the two Boot PROMs... <http://www.philpem.me.uk/code/3b1emu/3b1_roms.zip> Thanks are due to Michael Lee for providing the ROMs, and to Steven Hirsch for scanning the 3B1 TechRef, which started me out on this nutty little "write a 3B1 emulator" project... Enjoy! -- Phil. classiccmp at philpem.me.uk http://www.philpem.me.uk/

13 years, 5 months

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test-drb November 2010