test-drb August 2013

test-drb@ccmp.vtda.org

174 participants
181 discussions

by aw288＠osfn.org

Like the Sanyo just yesterday, I have a Compaq SLT/286 portable computer taking up space. Very nice condition, with power unit, dock, and bag. Any interest CHEAP? I am located in New York, zip 10512. Unlike the Sanyo, if there is no interest, I suppose I will just chop this up. I am desperately trying to clear out a bedroom to work on it - the bedroom that ends up being the junk overflow containment chamber. It would actually be nice to sleep in it sometime. William Donzelli aw288 at osfn.org

10 years, 7 months

TK-50 drive information

by saquinn624＠aol.com

Jerome and Jon opined: >> I normally use OLD (very rare and have been unable to find >> them any longer) wooden Q-tips. > > >In the US, try McMaster-Carr: http://www.mcmaster.com/#cotton-swabs/=o9xphz And Scott drivels: Or somewhere that does medical/dental supply. They're used in dental hygiene and surgery (the cardboard-shafted swabs go weak when they get wet).

10 years, 7 months

Apple Lisa Widget HDD

by ball.of.john＠gmail.com

>Does anyone know if Apple really manufactured the Widget HDD (circa 1983) >used on the Lisa or did they purchase the HDA from a supplier and add to it >their electronics? > >Tom Your first link is broken. ;) I thought the same thing until two things happened: 1: I got ahold of two Widgets and found that no, they are NOT similar to any other HDA assembly out there unlike that found in the Profile which uses the ST506 and ST412 assemblies from Seagate. 2: Digging through Apple's patents there's paperwork outlining the design of the drive which was voice coil and not stepper motor MFM like everyone else. It /might/ of been assembled in-house (there's no markings saying another factory did it so they might of actually run a clean room for HDA assembly) but it was obvious they designed the drive. -John

10 years, 7 months

Help identifying door / panel made by DEC

by p.gebhardt＠ymail.com

Hello there to the list, can any of the DEC-enthusiasts help me out in identifying what seems to be a front panel / door from DEC? It was part of a lot with RK07 drives, but this panel does not fit into any of the RK07 cabinets. http://classic-computing.dyndns.org/DEC_doorpanel/ Thanks alot for your help, Pierre ? ------------------------------------------------------------------------------- Pierre's collection of classic computers : http://classic-computing.dyndns.org/

10 years, 7 months

Five Toshiba 610CTs For Sale/Trade

by bearnold＠outlook.com

> > > > > I need to get a microphone for my podcast, and I've been advised that the Blue Yeti is what I need. So to come up with the $130 or so, I've got a lot of five Toshiba 610CT laptops for sale. > > Or trade if you have that mic. > > > > The lot is five laptops, four work, one does not. They are Pentium 90s, with 40 MB of RAM. Couple of different drive sizes, 1.2 GB, 800 MB, etc. > > Lot comes with one docking station, couple external floppy drives, an external CD-ROM, 7 or 8 power bricks, a couple of VGA adapters. Some spare parts like keyboards and keycaps and spare RAMs. Also included are PCMCIA modems and Ethernet combo cards. > > > > If anyone is interested I can give more detail. > > What's the type of display? Toshiba says they are 9.5 inch "True Color" TFT screens.

10 years, 8 months

XT-IDE V2 PCBs available

by LYNCHAJ＠YAHOO.COM

Hi! There are some XT-IDE V2 PCBs available if anyone would like some. They will cost the same as before ($12 each). However due to unforeseen extreme price increases in shipping by USPS I am forced to change shipping costs. Shipping in the US will be $3 for a single PCB and $2 for each additional PCB. Shipping internationally will be $10 for a single PCB and $3 for each additional PCB. This is for the bare basics USPS first class postage with no tracking or insurance. The builder assumes all risk of delivery as per usual arrangement. I apologize for the large price increase on shipping but this is out of my hands. The USPS is in dire financial trouble and is raising prices on shipping. It affects us all and is most unfortunate. These boards are provided "at cost" so there is no margin to absorb any shipping price increases. I have to pass them along. If you would like one or more XT-IDE V2 PCBs please send a PayPal to LYNCHAJ at YAHOO.COM http://www.vintage-computer.com/vcforum/showwiki.php?title=XTIDE+Rev2 There are about 10 XT-IDE V2 PCBs left. Thanks and have a nice day! Andrew Lynch

10 years, 8 months

Five Toshiba 610CTs For Sale/Trade

by bearnold＠outlook.com

I need to get a microphone for my podcast, and I've been advised that the Blue Yeti is what I need. So to come up with the $130 or so, I've got a lot of five Toshiba 610CT laptops for sale. Or trade if you have that mic. The lot is five laptops, four work, one does not. They are Pentium 90s, with 40 MB of RAM. Couple of different drive sizes, 1.2 GB, 800 MB, etc. Lot comes with one docking station, couple external floppy drives, an external CD-ROM, 7 or 8 power bricks, a couple of VGA adapters. Some spare parts like keyboards and keycaps and spare RAMs. Also included are PCMCIA modems and Ethernet combo cards. If anyone is interested I can give more detail. Thanks, Brad Arnold President & Cofounder, Atlanta Historical Computing Society http://www.ATLHCS.org http://www.AtariPodcast.com

10 years, 8 months

Apple Lisa Widget HDD

by tom94022＠comcast.net

Does anyone know if Apple really manufactured the Widget HDD (circa 1983) used on the Lisa or did they purchase the HDA from a supplier and add to it their electronics? FWIW there are photos of a Widget at http://www.classic-computers.org.nz/blog/2011-03-05-rejuvenating-a-lisa2-10. htm and http://www.flickr.com/photos/shockwaverider/7108067751/ Tom

10 years, 8 months

Suggestions Appreciated for a Program Counter History Log

by jhfinedp3k＠compsys.to

I know of only one example of a debugger which supports a Program Counter History Log. I am in the process of adding a Program Counter History Log to the System Debugger in RT-11 on a PDP-11. I would appreciate a few suggestions from anyone who has any experience with a debugger program which supports Program Counter History Logging. For users who are not familiar with PDP-11 hardware, the primary interface is a serial terminal, usually with 9600 baud these days (don't laugh - I first started on a PDP-11 around 1975 over a 300 baud modem), with a screen of 24 lines by 80 columns. There are a probably a VERY, VERY few systems which use VT420 terminals which can support 48 lines, but which are probably rarely, if ever used with other than 24 lines by 80 columns. From my point of view, the primary considerations are the lack of both speed (9600 baud takes seconds to fill a full screen) and available screen space to display more than about 200 addresses from the History Log Buffer (at 10 addresses per line). While I normally use the Ersatz-11 Emulator for the PDP-11 which provides me the possibility of using screens of 50 lines, I suspect that I am presently the ONLY person to interact with RT-11 using a screen of this many lines, let alone the speed of the screen which is so fast that the time between SCROLL and NOSCROLL is usually a dozen lines of output to the screen. At 9600 baud, the SCROLL vs NOSCROLL time delay is only a few dozen characters at most, certainly less than one line of output to the screen in almost all cases. The only experience I have with a debugger which has a History Log is with a 64 word buffer of addresses for the 64 immediately previous instructions. While this is often sufficient to at least pinpoint the general location of where the program stopped, it was often insufficient to locate where the problem started. For those who have direct PDP-11 experience, the following information might also be useful. At present, there are two buffers which can be displayed: (a) A buffer with 40 of the last interrupt entries to SD: which are composed of 5 words each: - Program Counter Address from the Stack - Program Status Word from the Stack - Word (instruction?) at that Address - Word (instruction?) at the Previous Address - Control Word which is used by SD: (PROSNG) (b) A buffer with the last 1000 Addresses of the last 1000 instructions that have been executed The current logic in the code to save each instruction address in the 1000 word buffer ONCE and ONLY once uses all five of the above values. There seems no point in displaying all 1000 addresses since only about 200 can stay on the screen and it takes too long in any case. However, just how useful are the past 1000 addresses as an aid in debugging? Since it takes no additional time for a larger circular buffer over a smaller circular buffer (in fact maybe a larger buffer is insignificantly faster) and there is memory available, I opted for the largest buffer that was reasonable The other buffer with the 5 word entries entries for the last 40 interrupts will be used when there are any questions about the exact details of any interrupt with respect to a user having set a Breakpoint or any other logic errors in the debugger in general and specifically when adding addresses to the 1000 word history log. NOW finally, here are my questions. Are there any suggestions as to how many previous instructions are needed to usually be helpful to have a log for when a program has a problem? Also, would it be useful to have the first word (two bytes) of the instruction as well as the address in order to identify the actual instruction or is the address almost always sufficient? On the PDP-11 with instructions being 1, 2 or 3 words, it is totally unlikely that having the addresses of the previous instructions would ever allow a user to confuse which code was previously executed unless two variants of almost identical code had been purposely constructed so as to confuse the user. This could occur when two overlays use the same addresses to execute that code, but it is almost impossible to happen by chance and even it it did, an extra NOP could simply shift the code for one of the variants so as to avoid the confusion. Jerome Fine

10 years, 8 months

Suggestions Appreciated for a Program Counter History Log

by mtapley＠swri.edu

At 12:00 -0500 8/27/13, Jerome Fine wrote: >Are there any suggestions as to how many previous >instructions are needed to usually be helpful to have a >log for when a program has a problem? Jerome, hopefully you'll get much better-qualified answers than mine; I have little to no experience programming assembly or PDP-11. That said, I can think of a few possible answers: 1) enough instructions that any timing-critical loop will be captured when an external interrupt dropping into the debugger is generated. This might be relatively short - 200 instructions or so? User (not necessarily programmer?) would set up and start a long calculation (mandelbrot set, whatever) and then hit "break", and be able to look back far enough to verify that the correct sequence of instructions is repeating over and over. For actual number, maybe look at the longest loop in RT-11 that repeats many times successively? 2) enough instructions that any timing-critical *subroutine" will be captured when dropping into the debugger. This would be a *lot* more, depending on application. In this case, the programmer would add a break point to the code right after the timing-critical routine (disk access, real-time control interrupt service routine, whatever) and then look back at the buffer to verify that the whole routine took the correct execution path. For disk access, that might be a *lot* of loops, though, so maybe you are only capable of writing a buffer to hold the last few iterations? For actual number, look at the longest single executable code unit in RT-11? 3) Configurable depth, configured at launch time for debugger Programmer gets to make the trade between debugger buffer depth and available memory for his program. Not sure any of this is helpful, and you probably have thought of it anyway. -- - Mark 210-379-4635 ----------------------------------------------------------------------- Large Asteroids headed toward planets inhabited by beings that don't have technology adequate to stop them: Think of it as Evolution in Fast-Forward.

10 years, 8 months

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test-drb August 2013