test-drb June 2012

test-drb@ccmp.vtda.org

193 participants
237 discussions

by jhfinedp3k＠compsys.to

Of the nine variants of KED developed by DEC, it seems doubtful that either K52 or K62 are in use at this point. I have mentioned in the past that a new variant, K42, which now supports a VT420 with 48 lines is available. Inspection of the code for K42 suggests that improvements can be made with respect to the allocation of memory. In particular, while K42.SAV is LINKed to execute under an Unmapped RT-11 Monitor, for versions of RT-11 which include VBGEXE, virtual memory can be used under a Mapped Monitor. These same improvements to K42 can also be added to K52 and K62 so that if these variants are executed under a Mapped Monitor, more efficient use can be made of the available memory. One of the improvements can be an increase in the size of the cut and paste buffer. If no one still uses a VT52 or a VT62 terminal, then there does not seem to be any point to including these improvements in K52 and K62. Please respond if there is any interest to actually use K52 or K62 under a Mapped RT-11 Monitor. Jerome Fine

12 years, 6 months

Tektronix 4052 Firmware

by rickb＠bensene.com

Hello, all, I have a Tektronix 4052 Graphic Computer that I believe is in workable condition, but the old Mostek MK36xxx-series mask-programmed ROM that holds the operating firmware for the machine have failed, which is apparently a common occurrence for these devices. I have found numerous mention of these ROMs having been used in test equipment that "forget" after 10 to 15 years after production. I found the archive of 4052 firmware on Bitsavers, but am wondering if anyone out there has any suggestions as to what to do to replace the failed ROM with something of more current technology that will work. The firmware consists of 64K bytes of code. The Mostek ROMs are 24 pin devices, 5V supply, that use a clocked chip select signal, meaning that any replacement will have to emulate the clocking access scheme. There were Motorola-made programmable devices that could directly replace the Mostek parts, but these seem to be virtually unobtainable today..and even if I could find 8 of them, I don't have anything that could program them. Any other 8K x 8 ROM is in a 28 pin package, which would require some clumsy adapters to work. Along with the ROM itself, the 4052 had a unique ROMpatch implementation that allowed up to 48 ROM locations to be ''patched' in real time, and this involved a PLA device that did the address matching, and a fast bipolar ROM that contained that data to be substituted at the location to be patched. Duplicating the patched code could also prove to be very difficult. I am wondering if anyone out there may have run into the same situation with a 4052 and came up with a solution. Any help would be greatly appreciated. Thanks, Rick

12 years, 6 months

VT14, other PDP14 options available

by useddec＠gmail.com

I have a complete VT14 (except for possibly the cover screws) 14/30, 14/35, and a lot of options available for serious inquires. It was going to be a project down the road, but I need to shorten my list due to health issues, Does any else out there have one, or even know of one? Please feel free to contact me off list. Thanks, Paul

12 years, 6 months

Homer lives

by spectre＠floodgap.com

This 9000/350 was Stan Sieler's, IIRC, and passed through an intermediary who couldn't maintain space for it, so I ended up with it and I put it in storage until I could get space myself. Now that I have space, Homer is resurrected. It is a 9000/350 (25MHz '020 + '881), 16MB RAM, 670MB main drive, HP-UX 8.0. And I still have 10b2 on my 10MBit backbone, so it plugged right in. http://www.floodgap.com/iv/1572 Testing the CPU (Homer doll came with it) http://www.floodgap.com/iv/1573 Self-test http://www.floodgap.com/iv/1575 Bringing up HP-UX http://www.floodgap.com/iv/1574 Old school X11 as God intended http://www.floodgap.com/iv/1576 Obligatory rear shot I figure Stan will enjoy seeing it's still out there and operational. -- ------------------------------------ personal: http://www.cameronkaiser.com/ -- Cameron Kaiser * Floodgap Systems * www.floodgap.com * ckaiser at floodgap.com -- The best defense against logic is ignorance. -------------------------------

12 years, 6 months

Z80 CPU microcode and internals

by dennis.yurichev＠gmail.com

Hi. I'm looking for any information related to Z80 CPU internals, microcode, sequencer, etc. Is it possible to rebuild it in Verilog/VHDL/TTL on breadboard with all that undocumented instructions, etc? Here is what I found so far about machine cycles, but obviously, it's not enough: http://www.msxarchive.nl/pub/msx/mirrors/msx2.com/zaks/z80prg02.htm

12 years, 6 months

PC-Write and PC-File Shareware

by swtpc6800＠comcast.net

I am doing my once a decade or so clean up and sorting. I have found working distribution diskettes of the shareware software PC-Write and PC-File. I had to break-out a 5.25 inch drive to read these. My 2005 vintage XP machine only support on drive at a time so I have to open the case and hook up the 5.25 inch drive. I have transferred these disks to my network drive and have tested them on a Windows 98 laptop. I also have Norton Utilities and various copies of DOS going back to version 1.1. (Complete with packaging.) If there are any vintage PC users here I can email copies of the disk contents. Is there a program that makes an "ISO" type file of a bootable floppy? http://commons.wikimedia.org/wiki/File:PC_Write_text_editor.png Michael Holley

12 years, 6 months

Interested in learning 68000 hard/soft

by rampaginggreenhulk＠yahoo.com

Andrew, Ive never seen its schematic, but the Apollo mobo I have is the most basic 030 Ive seen. Granted Ive really only gawked at Macs. Ill need to pull it out of storage. The only feature that stood out is a big ugly black chip that one might suspect was a mmu. It is a big mobo though. Maybe someone else can chime in.

12 years, 6 months

Weird Prices on E-Bay

by dave.g4ugm＠gmail.com

Folks, Any thoughts on what one of these is really worth? http://www.ebay.co.uk/itm/HP-7550-Plus-8-Pen-Colour-Plotter-Boxed-Vintage-Ra re-/130709681274 I know it is a high speed HPGL/2 capable plotter and I would really like it but $2000.... Dave Wade G4UGM Illegitimi Non Carborundum

12 years, 6 months

Found: paper tape for "L8/9" computer ... unknown

by dm561＠torfree.net

----- Original Message: Date: Wed, 20 Jun 2012 10:53:01 -0700 From: Al Kossow <aek at bitsavers.org> On 6/20/12 10:44 AM, Stan Sieler wrote: >> thanks for the kind offer! If Bob declines, I'll let you know. > CHM is interested, since apparently we have one. ------ Reply: Excellent; I assume that if they go to you there would be a way for someone who might need one to get a physical copy? m

12 years, 6 months

Found: paper tape for "L8/9" computer ... unknown computer

by dm561＠torfree.net

Original Message: Date: Tue, 19 Jun 2012 16:50:56 -0700 From: Stan Sieler <ss at allegro.com> > hi, > I found a box of paper tape software for an unknown computer (possibly a > "L8" or "L8/9"?) > ... and it's looking for a home (cost of mailing): > If anyone can suggest what computer it's from, I'm curious! > Stan ----- Reply: Hi Stan, Those are firmware and utility tapes for Burroughs series L8000 and L9000 computers, the predecessors of the B80 and B90 series and fairly rare since they were dismissed as mere 'accounting machines' and not considered collectible by purists and people without storage buildings: http://www.picklesnet.com/burroughs/gallery/bpgltc.htm Several museums have one and last I heard Bob Rosenbloom also had an L9000, as well as an L5000; I imagine he would be delighted to have those tapes and might even need one or two since I doubt that there are more than a handful of those tapes left in the world and some of them are crucial to the machine's operation. If by any chance there are no other takers I'd gladly take care of them for you and posterity. m

12 years, 6 months

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test-drb June 2012