test-drb May 1999

test-drb@ccmp.vtda.org

174 participants
659 discussions

by allisonp＠world.std.com

<> The first sector DOES NOT HAVE TO BE THE BOOT. < <Hi < It does on my system unless I toggle in a loader or have <EPROMs to do it. I'd like to not have any EPROMs if I don't <need it. The controller automatically loads track 0 sector 1. <I start executing at address zero and it boot loads the <CPM system. The boot loader then jumps to the start of <the CPM and it over writes info at address zero with what <it requires there. As far as I know, I am following the examples That is an example of the MDS800 style of boot. It is also fairly atypical of many. <for a non-MDS800 type system and following exactly what is <shown on 6-14/6-15 of the CPM manual that I got from the <unofficial site. The mapping shows that the first sector <is a cold start loader and the CPM ( CCP ) part doesn't start until <the second sector. Yes that config is specific to the MDS800 and that boot will likely NOT work with any controller in a IMSAI. If the controller in the imsai is the one I think it is (has an 8080 and an d372 FDC), the bios is simplified as that one does a lot of the work. I've built enough CPM system to have the configuration guide memorized. However I stopped going by the book as it's actually a bit to terse and does leave one to much imagination. The book by Andy Johnson-Laird The Programmers CPM Hand book is a must have for anyone doing bios work. Allison

25 years, 2 months

What's a "computer console" selectric called?

by amichael＠nortelnetworks.com

I'm not sure if it's the same kind of Selectric terminal, but about 20 years ago when I was trying to find an alternative to a Teletype to connect to my homebrew S-100 system, I acquired a used Selectric with a set of solenoids built inside its base to activate the printing mechanism. Maybe this is the model you remember. IBM had to make the base deeper to accommodate the extra actuating solenoids, so unless you placed the Selectric into a cutout or well it would sit too high above the desk for comfortable working. You'd energize solenoids in various zany combinations to tilt the type-ball correctly for each character. Electrical interface was through a 50-pin rectangular AMP connector at the rear, and I believe the solenoids needed 48 vdc. It weighed a ton. Actually, the biggest challenge in interfacing this thing to a computer was to sort out how to read one particular status signal from one of the microswitch contacts in the print mechanism, so your computer could start sending the next character at just the right moment before the mechanical cycle completely finished. Else your software had to pause a few milliseconds between characters, but there was a hidden menace awaiting if you took this easy way and just timed out for each character to finish. The starting-and-stopping would soon wear out the clutch mechanism. With the high duty cycle of computer printing (rather than manual typing) you would eventually put too much strain on the mechanism and wear it out if you didn't poll to respond to that "ready" signal. Many people don't realize the Selectrics were *completely* mechanical. No electronics, just complex and elegant mechanics. A nightmare :-) I gave mine away years ago. If I recall correctly it was a "Model 735 i/o Selectric". Maybe that name will help you track one down. I bought mine surplus from an outfit in England back in '77, but there were companies selling similar models in the USA too. They ran magazine ads in the early years of Byte and Kilobaud. There were some articles in Radio-Electronics (of Mark-8 computer project fame) describing a Selectric interface. Arlen > -----Original Message----- > From: Gary Oliver [SMTP:go@ao.com] > Sent: Monday, May 24, 1999 4:35 PM > To: Discussion re-collecting of classic computers > Subject: What's a "computer console" selectric called? > > Back in the days before "glass" consoles, computers often (if > they had them) used typewriter devices as console input and > output stations. Many minicomputers used Teletypes, but Control > Data used (believe it or not) IBM Selectric typewriters. > <snip> -- Arlen Michaels amichael(a)nortelnetworks.com

25 years, 2 months

non-SCSI disks on a SCSI disk interface (was Re: Space, the next frontier)

by fmc＠reanimators.org

ard(a)p850ug1.demon.co.uk (Tony Duell) wrote: > Yes, but have you seen the price of IDC DD50 plugs? Last time I needed > some, the standard 'Amphenol' 50 pin plugs (like overgrown Centronics > plugs) were a couple of pounds a time, but the DD50s were \pounds 17.00 > or so... Ouch! I've paid US$11.00 or so each (at Halted, in 1993), and didn't grumble too much because at that price it still beat the hassle of splitting a 50-wire flat cable to make it fit a solder-tail connector. -Frank McConnell

25 years, 2 months

Yet another freebie

by af-list＠lafleur.wfi-inc.com

More junk in the spring-cleaning frenzy here, to a good home: A Wyse50/350 keyboard, P/N: 840059-01 Aaron

25 years, 2 months

non-SCSI disks on a SCSI disk interface (was Re: Space, the next frontier)

by edick＠idcomm.com

IDC termination s for a 3-row connector are mechanically problematic. They're probably needlessly/intolerably fragile. Fortunately, external ribbon cables are no longer tolerated here in the U.S. They have been replaced with Pacific-rim-manufactured shielded cables which work quite admirably and which can be built into the DD50 with just as much integrity as the 2-row connectors. Those guys on the SCSI-II committee must have been software weenies, having picked the teensy and fragile high-density cable connectors they chose. I'd say they're every bit as likely to break as the microscopic things used in the "SCSI-III" connectors which look like the ones used on several of my PCMCIA cards. Fortunately, I'm too cheap to buy these most modern and extremely expensive connectors. I've got about two dozen of the old "Blue-Ribbon" (used in office phone systems) connector-fitted cables most of which I've had for years, used to tow the car, etc, and I've never had reason to cuss them. I have seven of the "SCSI-II" connectors on five cables, of which all but one are adapters. Only one of the adapters works right, i.e. their strain relief actually relieves strain, as opposed to pulling out. Of course, with them, I always know which end has the problem. I've not used the one with the little connector at both ends. I doubt I could fix it if it broke, which it surely will . . . 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: Wednesday, May 26, 1999 5:37 PM Subject: Re: non-SCSI disks on a SCSI disk interface (was Re: Space, the next frontier) >> >> It's odd that SUN, then, having declared the SCSI on the skids, would have >> been the ONE with the most sensible and least fragile connector on their >> external cable harnesses. If I had $1 for every time I've had a problem >> with external SCSI cable connectors, I could retire in luxury. I've NEVER >> had trouble with the D-types, in this case, the DD-50, breaking off >> contacts, etc. > >Yes, but have you seen the price of IDC DD50 plugs? Last time I needed >some, the standard 'Amphenol' 50 pin plugs (like overgrown Centronics >plugs) were a couple of pounds a time, but the DD50s were \pounds 17.00 >or so... > >I must admit they're (DD50s) a much nicer connector, though. > >-tony >

25 years, 2 months

Bringing up a CPM

by CLASSICCMP＠trailing-edge.com

> Still that doesn't explain the 7680 bytes in the file from >the site. I still don't know what to do. Well, 7680 bytes = 60 128-byte sectors, which is more than the first two tracks on an 8" floppy. I suspect that the "file on the site" is from an implementation where the boot track was double density or on something other than an 8" floppy. (30 256-byte sectors, 15 per track, maybe? Sounds like a 5.25" DD format.) According to my DR "CP/M 2 Alteration Guide", track 0 sector 1 is the cold start loader (bootstrap). Track 0 Sectors 2-17 are the CCP. Track 0 Sectors 18-26 and Track 1 Sectors 1-19 are the BDOS. And Track 1 Sectors 20-26 are the BIOS. This is for a plain-vanilla 8" SSSD installation, of course. -- Tim Shoppa Email: shoppa(a)trailing-edge.com Trailing Edge Technology WWW: http://www.trailing-edge.com/ 7328 Bradley Blvd Voice: 301-767-5917 Bethesda, MD, USA 20817 Fax: 301-767-5927

25 years, 2 months

"default" DHV11 CSR?

by mbg＠world.std.com

>Does anyone know the "default" CSR for the first DHV-11? (8x serial mux) >I'm trying to get one recognized in my uVax III with NetBSD and it's not >seeing it. There is no one set CSR assigned to the first DHV11... it depends on what else is in your system. The lowest address a DHV can be configured for is 17760020. Subsequent ones increase by 20(8). The vector also depends on what else is in the system. Since the uVaxIII has the config command, you might want to try using that, and enter all the devices on your system, and it will provide you with what the correct configuration should be according to the configuration rules. Just for the heck of it, I checked the RT-11 SYSGEN procedure to see what it uses for a default for the first DH-type interface, and that is 17760440. 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, 2 months

MVax II FOR FREE

by kees.stravers＠iae.nl

I am only relaying this message, please contact the poster. On 1999-05-27 bfarnam(a)skantech.net said: bf>I have an old MVax II (630QE Rack Cab, (2) RA-90, (1) TK-50, (1) bf>TS-05) that I need to move this weekend. I would like to find bf>someone who can put this hardware to good use, because come Tuesday, bf>it gets trashed. Do you know of anyone who would pick it up. It is bf>located in Greenville, North Carolina and I have UNLIMITED Licenses bf>for OpenVMS and DECNet in MY name that I will sign over. If bf>interested, or know someone that is, they can reach me via pager bf>during the day, as I don't check my e-mail that often at 888.511. bf>8830 or in the evening at 252.974.0162 bf>I thank you in advance for you time, bf>Brett A. Farnam bf>Washington, North Carolina -- Kees Stravers - Geldrop, The Netherlands - kees.stravers(a)iae.nl http://www.iae.nl/users/pb0aia/ I'm Sysadmin and DEC PDP/VAX preservationist - Visit VAXarchive! http://www.vaxarchive.org/ (primary) http://www.sevensages.org/vax/ (mirror) http://www.coyote.org/mirrors/vaxarchive/ (mirror) Net-Tamer V 1.08.1 - Registered

25 years, 2 months

"default" DHV11 CSR?

by cmcmanis＠freegate.com

Does anyone know the "default" CSR for the first DHV-11? (8x serial mux) I'm trying to get one recognized in my uVax III with NetBSD and it's not seeing it. --Chuck

25 years, 2 months

"default" DHV11 CSR?

by CLASSICCMP＠trailing-edge.com

>Does anyone know the "default" CSR for the first DHV-11? (8x serial mux) >I'm trying to get one recognized in my uVax III with NetBSD and it's not >seeing it. All but the earliest KA650's have a built in SYSGEN CONFIG utility which you can check for such answers. Under VMS, this is how it's done: $ mcr sysgen SYSGEN> CONFIG DEVICE> dhv11 1 DEVICE> [control-Z] Device: DHV11 Name: TXA CSR: 760440* Vector: 300* Support: yes As a side note, SHOW DEV from the >>> console prompt won't list things like serial multiplexers anyway. I suspect, however, that you're having a NetBSD problem and not a hardware configuration problem, as NetBSD for the most part completely ignores issues involving "standard" CSR's and Vectors. -- Tim Shoppa Email: shoppa(a)trailing-edge.com Trailing Edge Technology WWW: http://www.trailing-edge.com/ 7328 Bradley Blvd Voice: 301-767-5917 Bethesda, MD, USA 20817 Fax: 301-767-5927

25 years, 2 months

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test-drb May 1999