Hi folks,
Today was the first day of my free networking course at school, at the end
of which I will have received a certificate 'n stuff...anyway, the guy was
trying to explain layered protocol stacks, and data abstraction. It
occured to me that the concepts have no meaning outside the realm of
developing the protocols or applications that use these protocols. And
it's almost impossible to explain without referring to these realms. The
guy was telling us how 'everything in the computer is in binary' but you
need additional network layers 'because Word can't understand the binary
and needs it to be translated'. At this time, I was thinking about my
recent experiences with the PDP-8. I wonder, wouldn't it make everything
so much easier if every computer in schools had a PDP-8 emulator on it,
and students had to learn to make simple programs in PAL before learning
concepts like the OSI 7-layer model, etc? Because, it was obvious that
the guy was being forced to avoid saying the word 'function' or
'subroutine' since people didn't know what it meant....
--Max Eskin (max82(a)surfree.com)
<recent experiences with the PDP-8. I wonder, wouldn't it make everything
<so much easier if every computer in schools had a PDP-8 emulator on it,
For concepts closer to the computer hardware that would eb a good thing.
<and students had to learn to make simple programs in PAL before learning
<concepts like the OSI 7-layer model, etc? Because, it was obvious that
<the guy was being forced to avoid saying the word 'function' or
<'subroutine' since people didn't know what it meant....
It's unfortunate that the course was so top heavy with out a foundation
to hold it up. FYI: I have a copy of a pair of articles going back to
the only MicroSystems (1983) That explains it fairly well in only a
handfull of pages and then even provides a workable example wthat did
not require rocket science to make useful. However the idea of data
encapsulation, abstraction and arrays of data as objects are important
concepts that need to be learned between adding two number on a PDP-8
in PAL and the higher level application of 5GL languages and networking.
It's the side effect of knowledgeless people prescribing course goals and
content.
Allison
In einer eMail vom 06.03.99 22:42:56 MEZ, schreiben Sie:
<< > How does the 34010 do in handling bitmaps?
>
> The 34020 (and I believe the 34010 had that as well) deals with that
> through
> special bit-blit operations, bit-block-transfer and simultaneous
> logical/masking
> operations. This is much supported by VRAM hardware used at that time;
> the VRAM chips have bitblt features built in. The performance was
exactly
Are you sure about that? Most VRAMs (certainly the ones in use when the
34010 came out) seem to be nothing more than DRAMs with a second address
port that transfers one row of data into a shift register. The bitstream
from the S/R is fed to the video circuitry. No bit-blit operations.
The 34010 has instructions for raster operations (bit-blits) using data
anywhere in the address space, and they don't appear to depend on
features of the RAMs used.
-tony
>>
There is in fact both: the processor can do it, but at least the VRAMs
I looked at have some provisions for (simple) versions of that. What is most
important is to use the bit-plane masking facilities inside the VRAMs - at
least those
generations I looked at, maybe that was later than 34010 times.
John
-----Original Message-----
From: Derek Peschel <dpeschel(a)u.washington.edu>
>I'm not an expert on CPT, but I did have one of their dedicated word
>processors for a while. (It may have used a Z-80, I forget. It had 3.5"
>drives.) Do you know if your model was designed as a general-purpose
>computer or as a turnkey word processor?
This CPT 8525 has two vertical 8" drives to the right of that portrait
monitor. Very heavy also.
The 8" disks with it include CP/M and CBasic so it is not a dedicated word
processor.
Phil
On Mar 6, 9:22, Larry Groebe wrote:
> It occurs to me that one candidate would be the first batch of digital
> cameras.
> So made the first consumer-level digital camera? Kodak had a hi-end
> modified Nikon about 7 years ago, but I'm thinking the Apple QuickTake
> 100 is the earliest digital camera I can think of.
The earliest I can think of is the Canon Ion camera, about 1989, I think.
It used cute little 2.5" disks made by TDK and Sony. They looked like
3.5" microfloppies that had shrunk in the wash :-)
--
Pete Peter Turnbull
Dept. of Computer Science
University of York
In einer eMail vom 07.03.99 04:20:03 MEZ, schreiben Sie:
<<
Visiting a surplus shop today, I found a small herd of Tek Oscilliscopes.
Some
of them looked pretty old to me. They want real money for them too.
Details:
Model Mod 1 Mod 2 Cart
----- ----- ----- -----
564 3C66 2B67 1968 3C66 _NOT_ general purpose !!!
564 3A74 2B67 Y 1968 2 MHz four-channel storage
504 Y 1971 450 kHz single channel
561A 3A72 2B67 1961 650 kHz dual channel
5111 5A20N 5B10N too new for my docs
515A Y 1971 15 MHz single channel
549 1a1 Y 1973 30 MHz dual trace storage
D11 5A14N 5B10N Y too new
504 see above
564B 3A9 3B4 1968 unknown amplifier
Prices were originally $200 for most of them, except the 549, which was $400.
Some of them had been marked down to $100. They have some kind of automatic
decrease in price based on how long things stay in the store (1% per day?),
but most of them have been there only since late February. And I don't know
how that effects the ones that were "manually" marked down.
I suspect these prices are outlandish. The same place wants $25 for 2400
baud modems. :-) Anyway, the age-based discount may eventually make the
prices more reasonable. At least for the scopes, if not the modems.
The ones marked "Y" under "Cart" had a "Scope-Mobile" cart with them. But I
didn't think to get model numbers from those.
Oh, and I can't guarantee that these work. I didn't ask if they would allow
me to test them, and at present I don't know enough to be able to test them
anyway. I also can't guarantee that they'll still be there when I next
visit.
Questions:
0. How old are these guys? --- see above
1. Are any of these potentially useful for computer work? Can they handle
the
frequencies used in old machines, say, up to a few MHz? (Judging from
their
apparent age, I wouldn't hope for much more than that.)
2. Anybody want one? Be aware that in addition to the price tag, I wouldn't
expect these guys to be easy or cheap to ship. (At least one time in the
past I have had to back out of a deal because I couldn't arrange shipping
within cost & safety constraints.) And the carts are probably too big to
go through UPS or USPS. Given all that, if you want one, let me know.
Cheers,
Bill.
>>
1. There is a book about old Tek scopes available at
www.tubesandmore.com
Above info is from that book.
2. Today, you can still borrow microfiche from Tek of ANYTHING they ever
produced !! I did so for my 549 which is my main scope.
3. Here in the Munich area you find these things in the fleamarket
newspapers and web pages; typically they sell in the DM 150.-
to 450.- range. Right now there is a pretty nice 551 for sale since
several weeks, 27 MHz, TRUE dual trace (i.e., two electron guns),
you could probably get it for between DM 100,- and DM 200,-,
but shipping of course would be PROHIBITIVELY expensive.
If I did not already have three Teks, I would get it. These prices
INCLUDE checking it out before you buy !!
Regards
John G. Zabolitzky
Sorry to repeat this, but I forgot to change the subject and didn't want to
have start some thread of confusion (which it will I am sure anyway, but
sorry).
Once about every three weeks a place in Huntington Beach Ca has an auction
of computers, its not what it once was, but it still is entertaining. Main
course today was 1150 old 486 computers along with 500 other lots. I didn't
buy any of the 486's (just 10 macs), but I did see and buy some interesting
items.
Epson HX-20, circa 1983 portable computer with a microcassette for storage
and a builtin printer. This one has a expansion unit bolted to the side,
and a nice slim plastic case the whole thing fits into. It must have some
internal NiCads, but I haven't opened it up, and it didn't come with a AC
adapter (but 6 vdc isn't too tough). Looks extremely clean, including all
the rubber parts, like it spent much of the last 16 years in its case.
Skiwriter word processing software is builtin, so is basic, but the only
manual is for the former. Display is LCD 120x32, or 20 characters and 4
lines. Printer I suspect matches that. Almost forgot, one of its main
features are the ports, serial and full RS232 via 1/2 inch diameter round
connectors on the back.
Texas Instruments silent 700 terminal. Looks like a typewriter, with a
thermal printer and a acoustic coupler on the back. I toted one of these
around for a couple years in the earlier 80s with a pager, and I remember a
plastic suitcase, but this one is open.
A&J Micro Drive, date on the back is 12/6/85, this is some sort of tape
drive. The unit is small 1.5 x 3 x 5, runs on 4 internal AA batteries, and
has a cable with a DB25 shell and 6 pins in it. Tape sticks in the front,
slightly narrower than a audio cassette, and a lot thinner. Front reads
SYSTEM 100, A:, and a active/low battery light.
Things I didn't buy (and if somebodys wants requires quick action)
A pair of Digital LN03 laser printers
Xerox (I think) 645 S Memorywriter
Three boxes of circa 1988 full and half height drives, most with some sort
of card edge connection, others look very much SCSI.
The HX-20 looks too neat to part with, but if someone wants the 700 or
weird little drive I am open to it. The latter three big heavy items I am
willing to facilitate, but not get in the middle of.
To be down around $125, they've got to be in really sorry shape. I've seen
junkers sold for that. The 465B might be lower in price than its older
cousin the 465(A) because it's reputed to trigger less accurately than the
(A) as a result of the compromises made in that model update. I've never
seen proof of this, however. The 465's I've seen seem to sell around $400.
If they're in need of work, which would make them go cheaper, they don't
sell . . .
Dick
----------
> From: Marvin <marvin(a)rain.org>
> To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
> Subject: Re: OT? Tek Scopes
> Date: Saturday, March 06, 1999 10:36 PM
>
> Zane H. Healy wrote:
> >
> > I don't suppose there were any books for a "Tek 465B" scope? I picked
one
> > up a few months ago at the last CP/M swap meet, but don't have any
doc's.
>
> What are working 465s going for now? I have heard prices anywhere from
$125
> to $400 without probes.
-----Original Message-----
From: Joe <rigdonj(a)intellistar.net>
> I have a bunch of HP 150 stuff. Do you have a copy of the Sydex program
>that lets you read and write HP 150 disks on the PC? If so, I can E-mail
>you the DOS and some other programs
Cool Joe, I am sans Sydex.... shoot it over!
- Mike: dogas(a)leading.net
