test-drb April 2009

test-drb@ccmp.vtda.org

204 participants
261 discussions

Wanted: CompuPro, DEC, Hitachi, Sage items [clean text re-post]

by js＠cimmeri.com

I'm looking for the following items for various hobbyist educational projects I'm working on. Top hobbyist dollar paid. - CompuPro CPU-68k S-100 board. - DEC HSD05. - DEC BA353. - DEC BA350 w/ BA35X-VA pedestal kit. - Hitachi Superscan SVGA monitor, models CM1587 or CM1711. - Sage II 68000 computer. I'm in Maryland, so unless local would need shipping. Please reply with asking price and eBay handle if you have one. Thanks very much, jS (mdnttrain on ebay)

15 years, 3 months

Tek 40XX keyboard on epay

by rikbos＠xs4all.nl

190294196331 seller thinks it's made of gold.. -Rik

15 years, 3 months

Text differences

by bqt＠softjar.se

Fred Cisin <cisin at xenosoft.com> wrote: > On Sat, 4 Apr 2009, Ian King wrote: >> > Source files should not be giving you a 'record problem' (since they're >> > text) - but there is another potential issue. I downloaded some BASIC >> > source files on a PC, zipped them up and transferred them over to a VAX. >> > I picked one to compile (this is BASIC we're talking about), and it >> > failed with an error per line. I opened up the file in TPU and >> > discovered that there was a 'spurious' CR at the end of each line. I >> > removed those and everything compiled and linked. Take a look at the >> > line-level translation that may be happening. -- Ian > > New-line is not really standardized. Definitely not. > Although the machines may all claim to be using ASCII, > newline may be represented by > CR LF, > CR, > LF, > or LF CR (rarest) ...or just a record end. > The reasons are enough for a thread of its own. If you even think that you can find a reason. :-) 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

15 years, 3 months

Tape records

by bqt＠softjar.se

Richard <legalize at xmission.com> wrote: > In article <2877e57dba24bc750739ccec428ded28 at lunar-tokyo.net>, > Daniel Seagraves <dseagrav at lunar-tokyo.net> writes: >>> In article >>> <f4eb766f0904031640g7c90507eo92411f16365021e1 at mail.gmail.com>, >>> Ethan Dicks <ethan.dicks at gmail.com> writes: >>> >>>> Back in the day, we used to move copies around on magtape, bypassing >>>> all sorts of stream-of-bytes issues. Today, of course, most things >>>> expect streams of bytes, so that's how most things are presented. >> On Apr 4, 2009, at 12:53 PM, Richard wrote: >> >>> How does magtape avoid the stream-of-bytes issue? >> Magtape has blocks. > > What exactly is a block? > > Is it defined as a sequence of bits or as a sequence of bytes? > > If its just a sequence of bytes that define a block, I'm not sure I > understand how blocks avoid the stream-of-bytes issue. Good question. And people have some interesting answers as well. :-) A tape block is simply a bunch of bytes. The point is that it is a spcific number of bytes. A single read or write will process one tape block. This is important. It means that doing two consequtive writes for n bytes will not produce the same result as one write for 2*n bytes. It also means that if you request to read n bytes, and the tape block is shorter, you will not get data from the next tape block in addition to the current, but instead the read will return less data. Assuming the block is n bytes long, and you request a read for x number of bytes. If x > n you will get the whole block, but no more than the block. If x < n you will only get x bytes from the block, while the rest will be skipped. The next read will read from the next block anyway. Each block is physically separated from other blocks by a inter-block gap. This is meta-data that is not received as a part of a read, but which can be inferred from the number of bytes actually read, unless you get a data overrun error, in which case the block was larger than the read allowed for. In addition to this, you also have something called file marks. When you read and the tape position is at a file mark, you usually get a return value indicating that you read 0 bytes. This is a hint that it was a file mark you passed. Convention then have it that two consequtive file marks indicates the logical end of tape. However, ANSI-formatted tapes look and work slightly different, but that is all still implemented on top of the concept of tape blocks and file marks. Those two details are defined by hardware. This means that a tape can never properly behave like a stream of bytes. As I've said, Unix have a way of trying to make tapes look like a stream of bytes, but noone uses that, since it's not useful, nor meaningful. Even in Unix, you can control these things correctly from a program. That's what ioctls are for. 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

15 years, 3 months

Classic A/V equipment

by ics65＠sbcglobal.net

Does anyone know of any list, group or museum for vintage (1970s) professional Audio/Video equipment enthusiasts? Of course vintage computers were a part of some of this A/V equipment, especially for control systems. If this is off topic, any replies can be sent to my email directly ics65 at sbcglobal.net ,George

15 years, 3 months

Places to post for wanted vintage computer items?

by js＠cimmeri.com

*There's several old computer items I'm in the market for. Is this an appropriate venue to post? Any recommendations (besides here) for posting vintage "want ads"? Is it more effective to post an entire list within one post, or to have one post per item wanted? Thanks very much for any comments. jS *

15 years, 3 months

Keypunch that was on eBay

by quapla＠xs4all.nl

Hello Roger, Do you only need to convert the frequency for the motor or for the whole unit? If it is only the motor, you might look for a converter which is used for jukeboxes. Some people here in the Netherlands use a frequency converter for the motor which drives the turntable, the rest of the electronics does work without problems on 50Hz. Regards, Ed > Thanks for whoever it was who posted the info on the IBM 029 keypunch > on eBay. I have won it, nobody else bid. After it has been shipped > across the Atlantic I will have to think about converting it from 60Hz > to 50Hz. I have the remains of a 50Hz verifier which has a 240v / 50Hz > motor I should be able to use. Hopefully the rest runs on DC, so a > step down transformer before the transformers and bridge rectifiers > might be enough. Shipping costs more than the item of course. > > Anyone have any thoughts if it is worth trying the whole thing with > just a 240 - 110 transformer? If the motor burns out, not the end of > the world. > > > -- Certified : VCP 3.x, SCSI 3.x SCSA S10, SCNA S10

15 years, 3 months

The VAX is running

by bqt＠softjar.se

Richard <legalize at xmission.com> wrote: > In article <f4eb766f0904031640g7c90507eo92411f16365021e1 at mail.gmail.com>, > Ethan Dicks <ethan.dicks at gmail.com> writes: > >> > Back in the day, we used to move copies around on magtape, bypassing >> > all sorts of stream-of-bytes issues. Today, of course, most things >> > expect streams of bytes, so that's how most things are presented. > > How does magtape avoid the stream-of-bytes issue? By the simple fact that a tape is *never* a stream of bytes? Unix tries to mimic a stream of bytes on a tape, but as far as I know, noone wants that, and never uses it, instead going to the raw device, and doing all the operations a tape requires anyway. 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

15 years, 3 months

DIP IC test clips

by keithvz＠verizon.net

Hi there. I'm currently using "nose pickers" (a friend at work related that pleasant name) aka XKM grabbers (http://us.st12.yimg.com/us.st.yimg.com/I/webtronics_2042_10920298) to attach my low-cost pc-based logic analyzer to some old DIP chips. They are pretty nice but when you start using a bunch in a row, they can get pretty cumbersome. I'm looking for DIP IC test clips for both 40-pin and 48-pin chips. 40-pin doesn't seem too hard to come by, 48-pin seems harder. Here's a picture of what I'm basically looking for: http://www.ap-products.com/images/tc02.gif They clip on the already socketed IC and provide square male header pins on the top of the clip to attach. These are for personal use, and I don't want to spend $100 on clips. Anyone have a line on cheap clips or happen to have any around you want to get rid of? Thanks Keith P.S. I can find plenty of online datasheets from various manufacturers but trying to find a stocking reseller that will sell them onesy twosy to hobbyists is harder.

15 years, 3 months

DEQNA/DELQA cab kits the same or different?

by tiggerlasv＠aim.com

There are no operational differences that you'll notice between a DEQNA and a DELQA cabinet kit if you're using a PDP-11. There are two extra signal lines on the DELQA vs DEQNA cables, which correspond to "Control in, circuit "A", and "B". The purpose of these, I'm not sure; maybe some sort of throttling or flow control. I doubt the PDP-11 driver uses it. Not so sure about the MicroVax. For basic operations, with a DEQNA-compatible driver, the cables should perform identically, as they are pin-compatible. T

15 years, 3 months

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test-drb April 2009