test-drb March 2010

test-drb@ccmp.vtda.org

182 participants
231 discussions

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Anybody in Gardena CA like free old macs?

by teoz＠neo.rr.com

http://68kmla.net/forums/viewtopic.php?f=4&t=12990&p=126641#p126641

14 years, 2 months

Apple Lisa 1 for sale

by ukarmansalok＠gmail.com

Hi, Are you still selling this? Thankyou

14 years, 2 months

would this work?

by brianlanning＠gmail.com

Forgive my lack of hardware knowledge... What if I took this: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=310201616232&rvr_id=&crl… Desoldered the female ISA connector, then soldered it to the underside of a passive backplane. Would I have goofy reliability problems? Would it even work? brian

14 years, 2 months

Collection Reduction

by woodwp_98＠yahoo.com

Hello, We are located in the Raleigh, NC area and have a three car garage with a single room above it. We are planning on converting this to an apt for my son. The problem is it's full of stuff I've collected since the early 80's. The collection is heavily slanted towards early computers and electronics. These pictures are of a single room, just showing different views of the collection when it was spread out prior to storing it into stacks. eCollection ( http://www.flickr.com/photos/60147280 at N00/sets/72157622274120485/ ) My question is, does anyone know of someone local to the Raleigh area that could help us in the sale of this? Regards, WPW

14 years, 2 months

Honeywell CC690 uPAC

by adrian＠adrianwise.co.uk

I have a couple of uPAC modules from either a Honeywell DDP-516 or just possibly from a H316 machine. They're marked CC690. They're obviously some form of bus termination - just a series of clamp diodes to GND and some lines with pull-ups to +6V. The normal I/O bus termination on a DDP-516 is CC154, and I'm pretty sure that there is no termination uPAC needed on a 316. These were pulled from a machine in about 1984. I have some distant memory that they are an "upgraded" CC154 and can be used in place of a CC154. Can anyone confirm that - either from documentation or just from recollection? Adrian

14 years, 2 months

Bootable Model III disks...

by alhartman＠yahoo.com

C'mon guys... Nobody with a Model I and E/I with disk drives left it stock without a doubler of some kind... and... If you had the LNDoubler, you could do 8" and 5.25" (and now 3.5") single and double density disks all with the same board. I don't know of any board that only added 8" without adding a Doubler as well. I'm not saying there wasn't one... I just don't know about it. Percom, Tandy, LNW and Aerocomp made doublers. I think only the latter two supported 8" drives. Any Model I equipped with a doubler should be able to copy a Model III bootable diskette. Al Keansburg, NJ

14 years, 2 months

Solderless breadboarding (and 68010 vs 68000)

by ethan.dicks＠gmail.com

On 2/19/10, Tony Duell <ard at p850ug1.demon.co.uk> wrote: >> Yes, I have been using breadboards for more than 20 years and never >> had a problem with them. Sure, you must not try to stick thick wires > > I must have been unlucky. I tried several of them in my younger days > (Eurobreadboars, the CSC/GSC Protoboards, etc) and had no end of > problems. In the end I started just soldering upo the circuits on > stripboard, and my desigens started working first time. I've done both. I've personally never had mechanical stability problems with protoboards, but then I don't tend to wedge in 0.1" header pins into my boards. I insert ICs, 1/4W resistors, various capacitors, wires, crystals, LEDs and such, but rarely do I insert header pins. I've always felt that they were "too large", even though I know lots of people stuff them in there all the time. > [1] The local pound shop (a similar concept to dollar stores) was selling > a camping lamp with 24 white LEDs for a pound. I'd buy that for a pound! (and repurpose it, as you have). >> BTW, the article says it is an MC68008, so you did not need to count >> 24 pins (on one side) :-) > > Oh, I didn't . I noticed it was a 0.6" wide package. The 68000 and 68010 > DIL packages are 0.9" wide. Indeed. Quite distinctive. >> The 68010 is pin compatible to the 68000, but if you are in OS stuff, > > Indeed. There is also a PGA version of the 68010, which is used in some > HP machines IIRC there's a 68012 which had more addres mins bought out, > but otherwise had the same PGA pinout I have read about the 68012, but don't think I've seen one in the wild. >> you have to modify some software if you are handling stack frames. >> Those are not identical on the 68000 and 68010. > > IIRC, the 68010 pushes more onto the stack on an interrupt. It does. The difference isn't onerous - at least starting with AmigaDOS 1.2 if not 1.1 (not sure about 1.0), you could upgrade your 68000 to a 68010 for an approximate 5% effective speed "boost" - this was entirely due to the one-instruction DBcc "loop-mode cache" in random places in the OS and in applications. As long as your applications didn't try to execute any "MOVE from SR" instructions (http://www.cpu-world.com/CPUs/68010/), no changes were required. If you _did_ have some apps that did that, there a trap handler for that on, IIRC, an early Fish disk. It would catch the privilege exception, grab the status/condition code value and return the value to the trapping instruction. One app that was used to tell if you had the patch applied was the AmigaDOS 1.1 calculator. With AmigaDOS 1.2, the app made an OS call to get the required value. The older app used a "forbidden instruction" so it made a good test. If you are rolling your own OS or writing embedded code, it's not really that hard to determine what size of stack frame you'll have and handle both. I was responsible for replacing 68000s with 68010s in the final COMBOARD product (partially to take advantage of "loop mode" when dumping buffers across the DMA interface, increasing the block speed of the board with a $50 chip). I don't think the code changes relating to the 68010 took me more than part of an afternoon to implement. It's good to remember that it's so, but rather easy to accomplish once you are that deep in the code. -ethan

14 years, 2 months

HP 9825 tape drive

by rikbos＠xs4all.nl

I modified a HP 9825A tape drive for use with QIC 40/80 tapes. It's a rather easy conversion building a new capstand wheel witch is a little higher so it can drive the QIC tapes and increasing the write current by replacing a the current limiter resistor. It's under test and at the moment seems to work. I was curious if there others who did the same and what theire experiances are... -Rik

14 years, 2 months

flowcharts and teaching programming

by bqt＠softjar.se

uss Bartlett <arcbe2001 at yahoo.com> wrote: > Don't forget that the DO loop in Fortan has not the same effect as an iteration as the Do condition is performed at the end.? The DO component is therefore performed at least once.? An iteration must be able to be performed zero times.?? This was why in JSP it wasn't used. It differs. What you describe is how it is in FORTRAN IV and older. It was changed in FORTRAN 77, so that a DO loop can run zero number of times as well. Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt at softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol

14 years, 2 months

Identifying a classic board and find software for it ...

by gerhard.kreuzer＠liftoff.at

Hi, sombody donates a board to my collection, www.compuseum.at, maybe there is anybody outside helping me to identify this board. Its a PDP11 subsystem on an ISA board. Labels found: AT.S, PCCB ROI-931007. The PDP11 chip is one of this big nice ceramic carrier, holding two chips, numbers were: HD4-6900-5 DC334, produced 9338, and ...6901... repectively. As he told me, they used a standard OS2 box to run this 'machine'. He also will try to find something, but he isn't sure that there is anything left exept this nice board. As far as I know, it was part of a building management system, produced by Landis & Gyr and maybe used or co-developed by Siemens. Thanks for helping Gerhard

14 years, 2 months

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test-drb March 2010