test-drb

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101090 discussions

by hachti＠hachti.de

Hi, I have a TC02 DECTape controller for pdp15 available. Reasonable offers welcome. Regards, Philipp -- http://www.hachti.de

15 years, 10 months

Floppy disk data separators...

by herby1620＠yahoo.com

While I do understand that an external data separator is a good thing, I was one of those who did a design using the internal data separator using the WD1771 (and later National) chip. It was on a M6800 system I did some work on, and it seemed to work OK for me. I was using (originally) 35 track Seagate drives, but later used 40 track ones. I used 256 byte sectors (10 per track). If I git an error, I just did a retry. No real problems. Just my experience. I still have a system operational (I haven't turned it on in a few years, but may soon). I also interfaced various hard disks. What fun. It was 1976 and also worked on Qume (daisywheel) printers (it only takes a single PIA to interface to them!). I'm sure that others will have different views on data separators. My experience was a bit different, I don't know what I did different (maybe it was something!).

15 years, 10 months

amiga floppy disk reading experience

by keithvz＠verizon.net

The last two nights I've been busy archiving some of my Amiga floppy collection. Most disks were written over 20 years ago. On a sample size of about 150 floppies, most of them were perfectly readable by my homegrown usb external amiga floppy drive controller. I paid very close attention to the failures or ones where my controller struggled. Without sounding too obvious here, the time between the pulses (which more or less define the data) were grossly out of spec. The DD pulses should nominally be 4us, 6us, and 8us apart before pre-write compensation. Most good disks are slightly faster, and normal times for these ranges are: 4us: 3.2-4.2us. Many around 3.75us 6us: 5.5-6.2us. 8us: 7.5-8.2us (notice margins around 1-1.3us) My original microcontroller implementation was 3.2-4.2, 5.2-6.2, and 7.2-8.2. When my current FPGA controller would have a problem, I'd notice that there were problems right on a boundary. So maybe pulses were coming in at 3.1us apart instead of 3.2. Or maybe 4.3 instead of 4.2. So I kept bumping the intervals apart, making a larger range of pulse times acceptable --- the XOR sector checksums were passing, so I was likely making the right choices. The bits were ending up in the right buckets. But as I went through some of these disks, I ended up with the difference between ranges(and basically my noise margin) being reduced smaller and smaller. Some to the point where an incoming pulse time might fall darn smack in the middle of the noise margin. Which bucket does THAT one go into? My approach has been very successful(easily 95%+), but it makes me wonder about Phil's DiscFerret dynamic adaptive approach where a sample of the incoming data defines the ranges. Some disk drives and controllers might be faster or slower than others, and if you create custom ranges for each disk (each track?), perhaps you'll have better luck. Keith

15 years, 10 months

6809 transistor count?

by mcguire＠neurotica.com

Can anyone tell me the approximate transistor count of the 6809? -Dave -- Dave McGuire Port Charlotte, FL

15 years, 10 months

Emulex UC17 UNIBUS SCSI boards

by harry＠systemresale.com

I have a customer who may be interested . How much would you like to sell them for? -- *Harry McMaster* President P 519-763-3391 ext:223 F 519-763-9241 C 519-841-3391 www.systemresale.com <%3Fwww.systemresale.com%3F>

15 years, 10 months

asteroids board

by rdawson16＠hotmail.com

Hi Dan, If you still want to get rid of an non working asteroids board, count me in! I can fix the others too, if you wish. The problem for most folks is that they will need a vector type monitor, thats a little harder to find, but I see them out there for about $300. Wells Gardner if I recall. Here's a interesting page on the vector generator... http://jmargolin.com/vgens/vgens.htm Randy Dawson _________________________________________________________________ The New Busy is not the old busy. Search, chat and e-mail from your inbox. http://www.windowslive.com/campaign/thenewbusy?ocid=PID28326::T:WLMTAGL:ON:…

15 years, 10 months

DEC RQZX1 and KDJ11-E boot problem?

by bqt＠softjar.se

All right. Time to clear up some misconceptions, I see... :-) Nigel Williams <nigel.d.williams at gmail.com> wrote: > On Sun, Jun 13, 2010 at 3:11 AM, Zane H. Healy <healyzh at aracnet.com> wrote: >> Of course you may simply have some sort of hardware issue going on there as >> well, I'm not familiar with the RQZX1. > > The drives passes the built-in RQZX1 diagnostics, which includes > read/write/verify tests etc. I formatted the SCSI drive via the RQZX1 > too (prior to using the drive on Linux via SIMH to install RSTS/E), > just in case the format process was doing something special (although > I can't imagine what since I understand MSCP masks drive specifics). Well, when you format the drive on the RQZX1, the controller might put down some special information on the disk. But once you move that drive over to your PC, you are no longer talking MSCP, nor are you aware of any special areas set aside by the RQZX1, so you will most likely overwrite any such information making the formatting pointless. Ie, if the RQZX1 is putting some special information on the disk during the formatting, you cannot then take the drive to some other system and connect and use it there expecting things to not become messed up. However, if the RQZX1 does not put down any special information on the disk, what you do should work fine. But in that case, a formatting will not make any difference either. MSCP in a way do more than just "mask drive specifics". I don't have my RQZX1 manuals anywhere near, so I can't say more about any RQZX1 specific things. Sorry... > A next posible step is to use this source-code for a MSCP boot so I > can catch the initial boot load and see what is in the first disk > block (containing the next level bootstrap): > > http://www.slowdeath.com/AK6DN/PDP-11/M9312/23-767A9/23-767A9.lst I doubt that will help. I suspect that it is the controller which just throws an error back at the boot code when it tries to read the boot block. So nothing will be read. > I will also try a different model of SCSI drive too - perhaps the > Quantum Fireball is too much of a good thing (4200RPM 2.1GB); I have > an old clunker of a Quantum ProDrive 80S (3600 RPM 80MB!) > > Does anyone know how SCSI ID's are mapped to MSCP LUNs? so far the > RQZX1 appears to map the first SCSI ID (in my case #4) to LUN 0 (which > is what I want) - I am assuming it just does them in sequence. I would have thought that SCSI id #0 should map to LUN 0. #4 have traditionally been reserved for tapes (or was that CD?), although that could also have been #5 or #6. Johnny

15 years, 10 months

Cromemco Z2-D system and accessories in Seattle, WA - Wish to donate

by wysoft＠hotmail.com

I would like to note to all that the system has been claimed and given a new home. Thanks to all of those who responded. Jeff ---------------------------------------- > From: wysoft at hotmail.com > To: cctalk at classiccmp.org > Subject: Cromemco Z2-D system and accessories in Seattle, WA - Wish to donate > Date: Fri, 11 Jun 2010 20:02:41 +0000 > > > Greetings, > > I'm posting here to inquire about the possibility of someone wanting to take this old Cromemco off my hands. I appreciate all that it is, and it has some family history behind it, but no one else in my family seems to want it, and it's far beyond my era of interest, so... Here we are. > > The system itself is in good physical shape - no damage, structural or cosmetic. My late uncle also built a wooden rolling base for the system, which includes additional power outlets for peripherals, and a remote reset switch. He developed software for Boeing on this machine, and I imagine it was pressed a lot. > > Based on the advice of others, to avoid damage to the unit I have not powered on the unit or plugged it in. > > Hardware installed in unit: > CPU board, 4FDC, 8PIO, two 64KZ boards > > Additional hardware, still in boxes: > 16-FDC, four 16KZ boards, two WANGCO floppy drives > > Zenith Z-29 terminal is also included if you wish, though I had originally intended to keep it. I used it over a year ago to do VAX stuff, and it still worked. There is also a printed manual. > > Printed and bound documentation: > Word Processing System, Cromix Operating System, Database Management System, Cromemco Extended BASIC, Z-80 Macro Assembler, Link and Lib, CDOS, FORTRAN IV, Cromemco System & Components, Cromemco Trace System Simulator, Zilog Z-80 Tech Reference > > There's also a huge stack of assorted manuals, catalogs, etc. My uncle really kept everything. Also included are a fair amount of my uncle's scribblings and notes, some of which might be helpful to you. > > Software (almost too much to list): > CDOS 2.36, CDOS 2.54, Z80 Macro Assembler, Word Processing System 4.06 & 6.0, FORTRAN & utilities, CROMIX, Database Management System 3.05, Database Report Language 1.0, Relocatable Assembler, BASIC 5.2, 16K Extended BASIC, COBOL, Database 0.02 (?), Drivers (?) > > I'll gladly snap photos if you wish. > > I would really, really like to avoid having to dispose of this stuff. I never knew my uncle, but if I hadn't taken this stuff from where it sat for the past twenty years in my grandmother's basement, it would have ended up in the trash. Hopefully someone here can make good use of it. > > I'm in Bremerton, WA. I'll drive to meet you within a reasonable distance. Please let me know if you have any additional questions. > > Thanks, > Jeff > > > _________________________________________________________________ > The New Busy think 9 to 5 is a cute idea. Combine multiple calendars with Hotmail. > http://www.windowslive.com/campaign/thenewbusy?tile=multicalendar&ocid=PID2… _________________________________________________________________ The New Busy is not the old busy. Search, chat and e-mail from your inbox. http://www.windowslive.com/campaign/thenewbusy?ocid=PID28326::T:WLMTAGL:ON:…

15 years, 10 months

Making Amiga Disks...

by alhartman＠yahoo.com

I recently picked up an Amiga 500 on eBay. I may have some Workbench disks that will work with it. In case I don't. Does anyone have advice on how I can get disk images and make floppies from them readable by the A500? I have PC's and Macs with floppy drives available to make the disks. Thanks! Al

15 years, 10 months

Any HP80-seires experts around?

by ard＠p850ug1.demon.co.uk

Are there any HP80 seires experts here? I've got a curious quesiton. I am looking at the HP82909 128K RAM module (for the HP86/87 series). There are several places on the PCB that are not used -- from memory, thre are 4 locations for 14 pin ICs. More curiously, there's a place for a rssistor and transsitor to drive the ROMDIS/ line on the computer connector. I am pretty sure the 'missing' chips are simple logic functions. One is very probably a '74. Another may well be a '30. But I haven't worked out the details yet. My guess is that some HP product actually used this extra logic. So my 'curious quesiton' is : What product was it? -tony

15 years, 10 months

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