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)
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
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
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
*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
*
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
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
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.
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
