test-drb November 1999

test-drb@ccmp.vtda.org

211 participants
749 discussions

by edick＠idcomm.com

Please see embedded remarks below. Dick -----Original Message----- From: Tony Duell <ard(a)p850ug1.demon.co.uk> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Tuesday, November 30, 1999 2:16 PM Subject: Re: Needed: 1 IBM 8" alignment disk. >> It's search algorithm is really funny too: >> >> Read Sector <------------- >> If requested Sector <> address then | >> If CRC not okay then ---------------------| >> It's not as odd as you may think. The CRC is for the ID field, so it's got to keep trying to read the ID before it can determine whether it should read the following data field. The controller doesn't have a fixed number of retries, since the infinite loop, in the designers' opinion, allowed you to poke around with your instruments looking for the problem, and is probably as good as any other alternative. Remember, there's a CRC field after the ID field, AND one after the data field. They both must pass check before you get a valid sector. This behavior is, however, quite consistent with a misadjusted PLL, or whatever other mechanism they're using to extract the clock e.g. one-shots. If someone has fiddled with the pots on the device, all bets are off as to its ability to lock on the data. Since the data is synchronized differently on every sector, it should be easy enough to determine whether lock occurs just by triggering on the data stream while observing the PLL's oscillator. Each sector should show a discrete and easily visible acquisition window. Of course, that won't be the case with a naked but formatted diskette, since its data and ID fields were written in one fell swoop, with no asynchronism between sectors. However, if you format a new diskette on some OTHER and WORKING compatible machine, writing a file to it will be a sector-by-sector operation which will ostensibly have at least a short transient of phase change reflecting the difference in phase between the relative position of the diskette during formatting and during writing not to mention the minor speed variations. In any case, you should, with your oscilloscope set up properly, be able to watch a consisten acquisition of the data for each sector. If you're not getting that, which is what I suspect, then your error lies in that, the most basic task of a disk interface, without which NOTHING else having to do with data transfer will work properly. >> (you get the idea.. and infinite loop for most errors) > >Well, assuming it's getting into that loop, there's something to look at. >Does it find a sector address? Does it match (and should it match -- >don't overlook a possible comparator problem). Does the CRC match? Should >it? (again, don't overlook a possible problem with the logic here). > >Basically, you're in a loop (presumably stuck in some state(s) of a state >machine). You should be thinking about the following : > >What signals can get it out of those states? >Are they ever asserted? > >What events would cause them to be asserted? >Do those events ever occur? >What about the logic that detects said events and turns them into signals? > >-tony >

25 years

Obsolete media (was: Whats the screwiest thing you collect?)

by mbg＠world.std.com

>IMHO, it makes little sense to retain media for washing-machine-sized >disk drives if you don't retain the drives and maintain them in order to >retain the value of the media. Hindsight is always 20/20, but wouldn't >it make sense to archive data/software on an archival medium, likely, we >hope, to remain useable over time, rather than to store it on what's >intended for on-line storage, and is likely to become obsolete within a >couple of years of when it was developed? Unless there is no equivalent... I've got the exact problem with the DECsystem-10 I got earlier this year... it came with two RP06 drives. They are 3-phase drives. We don't yet have three phase power (or a close approximation of it), so cannot run the drives. Without the drives, we cannot even load the microcode for the machine, so it is a very large paper-weight. I've been looking of a non-three-phase replacement for the drives, but we still would need three-phase to get the data off the disks I have. We have, however, been getting all the data off the tapes so as not to lose it. It would be great if there was a massbus interface for a more recent tape drive, and the same for a disk... it would be neat to be able to have a DAT tape acting like a TU77 or something supported by the machine, and a couple of SCSI or even IDE disks acting as RM03 or RP06 disks... (anyone know of any? Anyone up for the challenge of designing one?) 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 | +--------------------------------+-------------------------------------+

25 years

Meshna

by dirtworks＠globalnetisp.net

Hi, My name is John Meshna. The son of the late John J. Meshn Jr., the Surplus mogel. I saw your post. I'm flattered that my father's memory lives on. We closed the company around 1988. He died in 1982. Thanks for keeping his memory alive. John > Home | Collection > > > > Software | Mailing Lists > > > > ------------------------------------------------------------------------ > [Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] > > Re: Keyboards > > ------------------------------------------------------------------------ > > * To: "Discussion re-collecting of classic computers" <classiccmp(a)u.washington.edu> > * Subject: Re: Keyboards > * From: Frank McConnell <fmc(a)reanimators.org> > * Date: 06 Dec 1998 15:57:48 -0800 > * In-Reply-To: Stephen Dauphin's message of Sun, 6 Dec 1998 13:13:21 -0500 (EST) > * References: <Pine.SUN.3.91-FP.981205235650.3615A-100000(a)osfn.org> > * Reply-To: classiccmp(a)u.washington.edu > * Sender: CLASSICCMP-owner(a)u.washington.edu > > ------------------------------------------------------------------------ > > Stephen Dauphin <ai705(a)osfn.org> writes: > > On a related note, wasn't there a electronics surplus dealer of some > > sort, perhaps based in Massachusetts, called "Meshna"? I'm wondering if > > someone knows whether they are still in business. Any web search turns > > up nothing. > > Here's info from one of their 1988 catalogs: > > John J. Meshna Jr., Inc. > 19 Allerton Street > Lynn, MA 01904 > Tel: (617) 595-2275 > > -Frank McConnell > > ------------------------------------------------------------------------ > > * References: > o Re: Keyboards > + From: Stephen Dauphin <ai705(a)osfn.org> > > * Prev by Date: Scanning Fiche > * Next by Date: Re: x86 OS's > * Prev by thread: Re: Keyboards > * Next by thread: Re: Keyboards > * Index(es): > o Date > o Thread > > > > > Created by: Kevan Heydon on Monday, 07-Dec-1998 15:10:16 PST

25 years

Frame buffer PMAGB-BA for DECstation

by hofer＠wgh.ch

Hello, I am looking for an inexpensive framebuffer PMAGB-BA for a Personal DECstation 5000/20. Some advices about good sources of DEC surplus ? Regards. J.-P. Hofer

25 years

TI Silent 700

by tom＠automatedtech.com

I'm working with a device which has poor documentation but it says the printer port is compatible with a TI Silent 700. Do you know what baud rate, character length and parity the Silent 700 used ? Tom Hickerson tom(a)automatedtech.com

25 years

Looking for Heath H89 software and some advice

by dmb＠itasoftware.com

I just got two Heath H89's to replace the one my parents took to the dump 10 years ago while I was away at college. Both these machines seem to work fine -- they will boot CP/M and I can run programs, etc. One of them is in absolute mint condition -- a real beauty. However, the vast majority of the disks I have (circa 1979) are HDOS disks. I would like to be able to read these disks and use the software (e.g., Walt Bilofsky's C compiler), but I can't get any of my bootable HDOS disks to boot. Would anyone be willing to make me a bootable HDOS disk and mail it to me? If so, I would greatly appreciate it. Let me know by email (dmb(a)ai.mit.edu) if you would be willing to volunteer. :) I'm also looking for any of Evryware's interactive fiction (text adventure) games for the H89. They had a whole series of these games (starting with "A Remarkable Experience") and I would like to resurrect them by porting them to a modern platform. (Yes, there are still people who like text adventures. See the Usenet newsgroup rec.arts.int-fiction for ample evidence of this!) Back in 1994, I ported Crowther & Woods' Adventure >from the original FORTRAN source (for PDP-10, I believe) to an object oriented language called TADS that was developed specifically for text adventures. This port was quite popular with the rec.arts.int-fiction crowd, and was itself ported to various other platforms, including Infocom's Z-Machine. I actually contacted one of the Evryware founders -- they're still making games -- but they said they don't have any copies of their H89 stuff anymore. So if anyone has them and would be willing to furnish copies, please let me know. Finally, does anyone know if it's possible to read/write H89 disks in a PC? I mean, I know that the disk format is radically different, but are PC 5 1/4" drives even physically capable of doing this? It would be very nice to have a PC-based program that could create H89 disks from disk images, and I'd love to write one, but frankly I'm a software guy and have no clue about the hardware side of floppy disk formats. If anyone has any sage advice, I'd be much obliged. Dave Baggett dmb(a)ai.mit.edu

25 years

Needed: 1 IBM 8" alignment disk.

by edick＠idcomm.com

please see comments embedded below. Dick -----Original Message----- From: Tony Duell <ard(a)p850ug1.demon.co.uk> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Monday, November 29, 1999 7:45 PM Subject: Re: Needed: 1 IBM 8" alignment disk. >> It isn't alignment as I can manually move the head very slightly back and >> forth which does affect the data coming into the controller assembly but >> does not help it find the actual sector... Therefore, hardware or an anlog >> adjustment >> >> I would like an alignment disk so I can use "their" tuning procedure to make >> this drive work quickly. It has a number of adjustments including : Clock, >> window, gap, etc... > These are not the usual things for which you'd want an alignment diskette. > >Most alignment disks do not include such tests (I am not saying that the >IBM one you asked for doesn't). They're just raw drive alignement disks >with catseye patterns for aligning the radial position, an index timing >burst, etc. > >If you think there's an electronic problem then you don't really need an >aligment disk. Start with the spindle speed, which I assume is right >since it almost certainly uses a mains-powered induction motor. Still, it >can't hurt to check that the index pulses occur at the right frequency. > >They'll be a master clock, probably also used for writing. Check this >with a 'scope or frequency counter. If it's incorrect, find out why. > Generally, there isn't a master clock. Among the drives I've been working on over the past months, none had onboard oscillators with the exception of the microprocessor-controlled Mitsubishi. That's why there are one-shots and the like. The writing is accomplished by using both outputs from a flipflop which is toggled by every positive edge on the data stream which is generated on the controller. > >Then take a formatted disk (format one yourself on your old CP/M machine >if you have to ;-)). Read a sector continously. Display the off-disk data >on one trace of a 'scope and the read clock on another. Does the read >clock seem to be the right frequency? Is it locked wrt the data? If not, >look at that read PLL (or whatever it uses). > Again, most drives don't have PLL's on them, but rather leave that to the controller. It does appear that this drive and controller may not be entirely separate. The adjustments for "window" and "gap" do sound like they are just trims on a one-shot, though. I've seen adjustments like that on old hard disks. As you may recall, almost all the early FDD's had FM clock/data separation on board. This drive is probably no exception. > >Index timing is either very important (if, for example, the controller >expects to see an address mark as the first thing after an index pulse) >or not at all important at this stage. > >At this point you should at least be recovering data bits from the disk. >So if it still can't find a sector, find out why not. Can it not find an >address mark at all?. Or can it not find the header you're asking for. >This is likely to be a digital problem. As I don't have schematics for >this unit I can't comment any further. > >-tony >

25 years

Needed: 1 IBM 8" alignment disk.

by dylanb＠sympatico.ca

-----Original Message----- From: Al Kossow <aek(a)spies.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Monday, November 29, 1999 10:05 PM Subject: Re: Needed: 1 IBM 8" alignment disk. >"I wonder if it really is working most of the way (i.e. it can read ID >marks and even data) but there's a problem getting that read data to the >CPU (shift registers, bus drivers, etc)." > >Are you trying this on your 8/I or 8/S ? The PDP-8i.. (it works the same on both units).. This drive has a dual buffer (50) and was made to be used on some of the slowest computers... The manual claims from high speed to "DC"... I have it on the 8i as I don't like to subject the 8/s to questionable hardware. > >>From memory, the Sykes interface is REALLY dumb. An 8/S might be too slow >to handle the data rates.. > It is... *really* dumb... Its got a 2 sector buffer option(claims it can do 2 things at the same time with the buffers) so I got a bigger really dumb controller. It's search algorithm is really funny too: Read Sector <------------- If requested Sector <> address then | If CRC not okay then ---------------------| (you get the idea.. and infinite loop for most errors) john PDP-8 and other rare mini computers http://www.pdp8.com

25 years

Needed: 1 IBM 8" alignment disk.

by dylanb＠sympatico.ca

-----Original Message----- From: Tony Duell <ard(a)p850ug1.demon.co.uk> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Monday, November 29, 1999 9:40 PM Subject: Re: Needed: 1 IBM 8" alignment disk. >> It isn't alignment as I can manually move the head very slightly back and >> forth which does affect the data coming into the controller assembly but >> does not help it find the actual sector... Therefore, hardware or an anlog >> adjustment >> >> I would like an alignment disk so I can use "their" tuning procedure to make >> this drive work quickly. It has a number of adjustments including : Clock, >> window, gap, etc... > > >Most alignment disks do not include such tests (I am not saying that the >IBM one you asked for doesn't). They're just raw drive alignement disks >with catseye patterns for aligning the radial position, an index timing >burst, etc. > I hear you. This particular drive claimed it did. >If you think there's an electronic problem then you don't really need an >aligment disk. Start with the spindle speed, which I assume is right >since it almost certainly uses a mains-powered induction motor. Still, it >can't hurt to check that the index pulses occur at the right frequency. > That's all working fine... It's controller has a serious status system in it where it monitors disk spindle speed, etc... >They'll be a master clock, probably also used for writing. Check this >with a 'scope or frequency counter. If it's incorrect, find out why. > One master clock.. 1Mhz, good.. A board dedicated to "data timing". >Then take a formatted disk (format one yourself on your old CP/M machine >if you have to ;-)). Read a sector continously. Display the off-disk data >on one trace of a 'scope and the read clock on another. Does the read >clock seem to be the right frequency? Is it locked wrt the data? If not, >look at that read PLL (or whatever it uses). > Good idea on the CPM unit. I rarely use/see one so I will format one and start that way. >Index timing is either very important (if, for example, the controller >expects to see an address mark as the first thing after an index pulse) >or not at all important at this stage. > Not there yet. >At this point you should at least be recovering data bits from the disk. >So if it still can't find a sector, find out why not. Can it not find an >address mark at all?. Or can it not find the header you're asking for. >This is likely to be a digital problem. As I don't have schematics for >this unit I can't comment any further. > It can't find a sector *most* of the time.. Once in a while I can get it to read and display a sector correctly... The rest of the time it is in an infinite loop. What bugs me is sometimes I can read a sector with a good CRC and the data is correct... probably *another* bad solder joint... this box has been filled with them so far. Thanks for the CP/M idea. >-tony > >

25 years

OT: Swords (was: Re: Whats the screwiest thing you collect?)

by Philip.Belben＠powertech.co.uk

>>>> >Wow. My collection of sharp objects are strictly modern >>>>reproductions. To >>>> >the point where I took them to the vet and had 'em xrayed to see if >>>>they were >>>> >correctly made. Some were, come weren't. Sold the ones that weren't. >>>> > >>>> >> Swords can be neat, I have a friend who recently sold a japanese >>>>sword for >>>> >> $40k to one of those roving sword buyers. Some local yard sale had a box >>>> >>>> This one was 650 years old, made by one of the best, and used in some major >>>> ceremony. My friend estimated it will sell for 4 times as much in Japan. >>> >>>One wonders where your friend got the thing. I was under the impression >>>they're >>>illegal to export from Japan. (not sure where I got that impression though) >> >>Apparently a lot of swords were lost in WWII and found thier way to the US. >>The Japanese families that lost these swords are willing to pay big bucks >>for them if they can be found. > > Japanese I believe sometimes would "surrender" their swords as a formal > gesture. GIs would also rob bodies, etc. Getting them back to Japan is a > fair sized industry. Wow! Quite a thread for one so far off topic. In no particular order: At the surrender at the end of WWII, swords were formally handed over by commanding officers (of ships etc.) as a gesture of surrender. This is a western custom as well as (rather than?) a Japanese one. Seems strange that they handed over valuable antiques, but it is the sort of extravagant gesture that goes with a culture that commits ritual suicide... I will admit to having two swords, but I am not a collector. One is a modern fencing foil with a rubber tip. The other, that I think of as "my sword" (even though my brother has an interest in it) is a bit more interesting. It is the sort of sword that officers in the Royal Navy wore with dress uniforms up to about 1914 (when the design changed slightly). It belonged to my grandfather, so I assume he was commissioned as a midshipman (US: ensign) at age 16 (in 1913). He may have upgraded later to the newer design, but if so, this went to the bottom of the sea with him in 1944. The sword was made by Wilkinson (lately of razor blade fame but in his time the UK's leading sword manufacturer) and sold by Gieves (a well known supplier of uniforms, known in the services as Thieves), and it bears the number (which may be a serial number) 56500. The test of such a sword was not whether a handkerchief would fall in two pieces if dropped on the blade ;-) - in fact, mine has never been sharpened - but whether you could bend the blade so that the tip would touch the forte just below the hilt. Swords that passed would have a "proof mark" set into the blade at that point. Wilkinsons reps used to demonstrate this, but it was said that Gieves' swords made by anyone else, although they bore the proof mark, would be damaged if you tried it... My sword is somewhat corroded. I got someone to clean off the worst of the rust; he cleaned of "as much as he dared", which unfortunately reduced the clarity of the designs etched into the blade, so this may have been a mistake. Nonetheless, for such a heavy piece of iron (though not relative to my computer collection!) it is amazingly well balanced. I wouldn't have any difficulty wielding it in a fight, even though the grip is a bit too small for me. FWIW I am told that swords should be preserved with suitable grease. Suitable = hydrophobic. In particular, lube oil / axle grease etc. are NOT suitable. Petroleum jelly is recommended; I have heard of olive oil being used; and I imagine silicone grease and some of the water displacing penetrating oils would also work. FWI also W I have some small skill in European fencing (although I haven't done any for a few years now), but have never studied Kendo... Philip. ********************************************************************** 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 for the presence of computer viruses. Power Technology Centre, Ratcliffe-on-Soar, Nottingham, NG11 0EE, UK Tel: +44 (0)115 936 2000 http://www.powertech.co.uk **********************************************************************

25 years

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test-drb November 1999