test-drb February 2013

test-drb@ccmp.vtda.org

185 participants
407 discussions

Garbage on screen when using real VT100 on emulated PDP-11

by earl＠retrobits.com

Also posted this question in the Vintage Computer Forums. OK, I'm stumped. I'd like to use a real VT100 as a terminal with an emulated PDP-11 running RT11. When the VT100 is connected to a real PDP-11, it works fine. When connected to the emulated PDP-11, garbage characters begin to appear on the screen when, say, doing a DIR command. The garbage always starts in exactly the same place in the DIR listing. After that, garbage characters (grey squares) become interspersed with the good text. I have tried this with SIMH under Linux, connecting the VT100 to the serial console port of the Linux machine. I've also tried it under E11, using that program's built-in serial terminal capacity. Same exact error in both cases. I've looked at the RT11 SET command for TT: to see if there are any applicable parameters. Can't find any. I've set the SIMH TTO device to all its possible settings: 7B, 7P, 8B, and UC. Same stuff in all cases. I've looked at the serial settings on the VT100 to ensure 8 bits, no parity, and correct baud rate. All good. The VT100 works fine with the Linux box doing Linux-ey things. No character corruption when doing a big "ls" listing, OK with vi, etc. The SIMH and E11 emulators work fine in their virtual consoles, with no character corruption when doing a DIR, etc. Any ideas? I'd really like to, for instance, get my Raspberry Pi to be a mini PDP-11 system, but I can't get past this character garbage when using the real VT100. Help appreciated! And thanks for reading! - Earl

11 years, 2 months

PDP8 Omnibus to USB interface

by hachti＠hachti.de

Hi folks, I'd like to introduce my newly designed Omnibus-USB interface. I designed a quite well working prototype of something that looks like a KL8E for the PDP8 and like a serial port on the PC - but is none of both :-) It ist not meant as a console terminal replacement (which it could be used as) but as an alternative IO device used to dump (archive!) and restore mass storage media. To the people who don't know the problems of having MASSES of disks and tapes to dump: Please don't flame. Pictures and some more information can be found on my website: http://pdp8.hachti.de?gallery/omnibus_usb My intention is to design an improved (probably full height) version and do a little production run. As I'm currently out of work, selling those boards could help a bit. I can do it only if I get enough preorders. So I ask everybody with serious interest to tell me how many boards he wants and how much he could spend. Based on that feedback I'll decide if I can do it and fix a price. It won't be cheap - but very helpful and cool! I'd really like to make some more. It would be great if there's enough interest to do it. If you have any suggestions, let me know! Kind regards, Philipp :-) -- Dipl.-Inf. (FH) Philipp Hachtmann Buchdruck, Bleisatz, Spezialit?ten Alemannstr. 21, D-30165 Hannover Tel. 0511/3522222, Mobil 0171/2632239 Fax. 0511/3500439 hachti at hachti.de www.tiegeldruck.de UStdID DE 202668329

11 years, 2 months

Strobe plotter documentation or information?

by Carl.Claunch＠gartner.com

I have it all worked out and tested. It was a parallel IO board using an 8255A, with TTL signals driving the two stepper motors and pen solenoid. TTL 5V signal to one of the four poles of the uniphase stepper motors moves it 3.6 degrees, the operator buttons are reported as inverted TTL signals, no protocols or intelligence at all in the plotter so my job was dead simple. The 20 wire ribbon cable is the six button inputs, the eight stepper motor outputs and the pen solenoid output, plus a ground return. The operator buttons, for example to move the pen to the right, are sent to the computer whose driver would have to step the motor, rather than occurring locally in the plotter. Did I mention that it had zero digital logic chips or intelligence? Nine transistor drivers, a power supply and a few pullup and current limiting resistors, plus the steppers, solenoid, switches and buttons. If anyone else ever needs one, I have documented the cable assignments here so that they are searchable on the web. I will also mention the S-100 bus card assignments to the 8255A ports in case someone wants to use it with a retro machine through the interface card. Pins 1, 2, 4 and 5 are not connected. Pin 3 is ground Pin 6 is inverted TTL input, status of the "start/enter" button on the cover, port PA5 Pin 7 is the central "fast" button for pen movement, inverted TTL input, port PA4 Pin 8 is the "pen right" button, inverted TT input L, port PA3 Pin 9 is the "pen left" button, inverted TTL input, port PA2 Pin 10 is the "pen down" (actually rotate drum and paper up) button, inverted TTL, port PA1 Pin 11 is the "pen up" button, inverted TTL input, port PA0 Pin 12 is the output to activate the pen solenoid so that the pen is marking the paper, TTL 5V to activate, port PB4 Pin 13 is the output for one pole of the drum movement stepper motor, TTL 5V on this and 0 on the other three, port PC3 Pin 14 is the output for a second pole of the drum movement stepper motor, TTL 5V activates, port PC2 Pin 15 is the output for a third pole of the drum movement stepper motor, TTL 5V activates, port PC1 Pin 16 is the output for a fourth pole of the drum movement stepper motor, TTL 5V activates, port PC0 Pin 13 is the output for one pole of the pen left-right movement stepper motor, TTL 5V on this and 0 on the other three, port PB3 Pin 14 is the output for a second pole of the pen left-right movement stepper motor, TTL 5V activates, port PB2 Pin 15 is the output for a third pole of the pen left-right movement stepper motor, TTL 5V activates, port PB1 Pin 16 is the output for a fourth pole of the pen left-right movement stepper motor, TTL 5V activates, port PB0 For those not familiar with stepper motors, they have four poles each with a ring of 25 'teeth' that will attract a permanent magnet on the rotor. The four rings are staggered so that in total there are 100 positions around the dial - 3.6 degrees per step. Energize one pole and the magnet is held to the nearest tooth of that pole. Drop that pole and activate another whose tooth is adjacent and the rotor swings one position to hold at the tooth on that pole ring. Interface is a simple four bit circular shift register with one high and three low bits circulating in the pattern. Shift it once and the motor moves one step in the associated direction. Carl ________________________________ This e-mail message, including any attachments, is for the sole use of the person to whom it has been sent, and may contain information that is confidential or legally protected. If you are not the intended recipient or have received this message in error, you are not authorized to copy, distribute, or otherwise use this message or its attachments. Please notify the sender immediately by return e-mail and permanently delete this message and any attachments. Gartner makes no warranty that this e-mail is error or virus free.

11 years, 2 months

Dust-cover material

by wilson＠dbit.com

This is a dumb one, but: There used to be commercially available dust covers made out of translucent plastic (vinyl???) that fit over terminals, monitors, printers etc. (and I think there was a full line of custom-fit ones for ham rigs too). It seemed silly at the time but now that I'm chest-deep in old computers/terminals/ peripherals, some of the stuff goes many years between uses and the dust is a real problem. So ... I have a sewing machine (yes older than my computers and come to think of it, it gets dusty too) and more patience than I deserve, but I can't find a source for the kind of plastic sheeting I mean. Hardware-store drop cloths are too flimsy (might as well just use a trash bag) and I've gotten nowhere googling, but maybe that's just because I don't know the correct name. Anyone know what I'm talking about, and where to get it by the yard etc.? Thanks! John Wilson D Bit

11 years, 2 months

Raspberry Pi

by rampaginggreenhulk＠yahoo.com

I'm sure many will agree this exchange is one for the annals. I can't stop laughing. And to think I started it all by yelping about that damned Acorn!

11 years, 2 months

Raspberry Pi

by rampaginggreenhulk＠yahoo.com

http://www.extremetech.com/computing/148482-the-true-cost-of-a-raspberry-pi… I'm still not knocking it. But what adult male is going to want a Pibow??? Oi vay My idea of a generic netbook case with perhaps a few exchangeable bezels to accommodate various surplus lcd's makes more sense to me. But I hear no mention of the pi supporting a raw lcd panel, like my pmmx sbc's do. Is there any provision for that at all?

11 years, 2 months

Raspberry Pi

by rampaginggreenhulk＠yahoo.com

------------------------------ On Wed, Feb 27, 2013 1:55 PM PST Tony Duell wrote: >Programming I will grant you, although $deity help you to figure it out ... *puzzled look* Is that particular $deity more responsive based on what you toss in the plate? Perhaps we can arrange a sort of $group $buy wink wink and coerce said $deity into getting a truly hackable piece of fruity dessert on the market.

11 years, 2 months

PDP-11 / Unibus: config info for Motorola Memory Systems MMS1117 MOS board?

by js＠cimmeri.com

cctalk-request at classiccmp.org wrote: > Subject: > Re: PDP-11 / Unibus: config info for Motorola Memory Systems MMS1117 > MOS board? > From: > ard at p850ug1.demon.co.uk (Tony Duell) > Date: > Sun, 24 Feb 2013 19:37:05 +0000 (GMT) > > To: > cctalk at classiccmp.org > > >> >> > Folks, I'm restoring an 11/34A. One of the MOS memory boards it came >> > with is a circa 1979 Motorola model "MMS1117", variation "58 PC" >> > (64KWords / 18 bits / w/parity). Would like to know if anyone out >> > there has configuration information for this seemingly uncommon board? >> > It's a very high quality board and has socketed RAM, so it'd be >> > especially nice to be able to keep using it. It has 5 switch packs >> > (only 2 of which have markings) and at least a dozen jumpers. >> > > I had a similar problem when I got my first PDP11 (a PDP11/45). The donor > had wanted to keep the memory that was used in it, he gave me what I > later discoveed to be a 32KW MUD board (actually, it could be populated > right up to 128KW, of course only 124K of those would be useable). I had > no idea how to set the swiches, or indeed, what sort of backplane wiring > I would need to use it . > > This was logn before the days of the web. so there was no way to ask > others what to do. > > And I got it working. I spent a few weeks tracing out the scheamtics of > the unknown board and figuring out just what all the switches and jumpers > did. A long job, sure, but IMHO worth it. > > -tony Wow. Do you recall how many layers the PCB had? I'd be interested in seeing a sample scan of the schematic you laboriously produced, just to get an idea of technique. The web has certainly made hobbies like this unimaginably easier, if not just possible at all. - jS

11 years, 2 months

Garbage on screen when using real VT100 on emulated PDP-11

by cctech＠beyondthepale.ie

> > The VT100 doesn't need padd characters IIRC (VT05 and VT52 definitely > do), but it uses a signalling scheme to tell the host that it's > internal buffer is full. This signalling scheme can be either in the > hardware signalling (DTR/CTS) or it can be XON/XOFF (DC1/DC3) control > characters in the data stream. > According to my VT102 manual, DTR is only turned off when the terminal is offline or performing a line disconnect. It doesn't seem to turn off DTR or any other signal in response to the input buffer becoming full. Under "Input Buffer Overflow Prevention", it goes on to say that there are three methods of input buffer overflow prevention and lists XON/XOFF, fill characters and low speed operation. A table shows the requirement for fill characters for various functions at various baud rates. It suggests that all functions require at least one fill character (null) at 9600 baud, even when not in smooth scroll mode. Regards, Peter Coghlan

11 years, 2 months

Raspberry Pi

by rampaginggreenhulk＠yahoo.com

Now now Mardy. We can disagree w/o being hilarious. ------------------------------ On Tue, Feb 26, 2013 7:08 PM PST Mardy Marshall wrote: >Raspberry Pi - The Chia Pet of Personal Computers > >-Mardy >

11 years, 2 months

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test-drb February 2013