Another interesting thing I noticed this evening is that the color scheme
of the PDP-8/f is subtley different than the scheme of the 8/m. The Rust
colored handles are the same but the brown ones are more yellow. Megan's
got a picture of the green one that was the 'lab' 8. How many were there?
--Chuck
(who thought he had extra 8 switches but finds he has mostly extra 8/m
switches)
At 21:27 29-03-1999 -0800, you wrote:
>On Mon, 29 Mar 1999, Bruce Lane wrote:
>
>> Actually, ASR-33's ran at 110 Baud rather than BPS.
>
>Same difference.
>
>(you were just joking though, I'm sure)
No I was not, and it's not necessarily the same (contrary to popular belief).
From 'Data Transmission, Second Edition' by Tugal and Tugal (McGraw-Hill,
1989), Pages 133-134:
"...The transmission rate is generally expressed in Baud (Bd). Although in
most systems it is equivalent to bits per second (b/s), the baud
transmission rate must not be confused with the information rate, bits per
second, the rate at which actual data are transmitted. One baud signal may
carry one or more bits of the data..."
The book goes on to detail some specific examples. In essence, in a case
where QAM (Quadrature Amplitude Modulation) is used between a pair of 9600
b/s modems, every discrete change in the signal represents four bits.
9600/4 = 2400, so the actual 'baud' rate of such a signal is 2400, even
though the bits/second is 9600.
They give another example specifically related to the transmission of
ASCII code where the baud rate is representative of the total number of
bits in a single character (11 in their example, made up of 8 data, 1
start, and two stop bits).
Anyway, it makes a good read. The book itself may be a bit dated, but the
principles don't change.
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Bruce Lane, Owner and head honcho, Blue Feather Technologies
http://www.bluefeathertech.com
Amateur Radio:(WD6EOS) E-mail: kyrrin(a)bluefeathertech.com
SysOp: The Dragon's Cave (Fido 1:343/272, 253-639-9905)
"Our science can only describe an object, event, or living thing in our own
human terms. It cannot, in any way, define any of them..."
At 09:48 PM 3/29/99 -0800, Sellam wrote:
>On Mon, 29 Mar 1999, James Willing wrote:
>> At 08:37 PM 3/29/99 -0800, Sellam wrote:
>> >
>> >Does anyone know what the function of an IBM 557 Alphabetic Interpreter
>> >is/was?
>>
>> ... and yes, if you had not guessed... I still have a manual on how to
>> program these things!
>
>Cool. I especially liked the patch panel. I'd love to learn how to
>program the thing.
OOH!!! I see a program for VCF III coming on! "Progamming IBM Unit Record
Equipment"! You will have to find a couple of more pieces tho...
We'll need a keypunch, a sorter would be nice, (I have both of those, but
they are a bit hard to move that far), a reproducer would probably be
excessive, but a tabulator or calculator would be just keen! (WARNING -
IBM had a REAL interesting definition of "calculator") A collator might be
fun too...
>> (now, if I could just remember that trick that we used to teach a 402
>> tabulator how to multiply... B^} )
>
>Are you implying these things had some general purpose computing
>attributes?
Yes... (BTW: brain fart - it was a 403 that we taught how to multiply)
The Tabulators could do addition, subtraction, and summary functions (basic
accounting machines) controlled by the programming on the plug board.
The Calculators could also do multiply, divide, and logical functions.
Again, controleld by plug boards and the cards...
Any which way... watch out what you ask for! I can probably still teach
someone how to program these things! B^}
(Damn, I'm starting to feel old!)
-jim
---
jimw(a)agora.rdrop.com
The Computer Garage - http://www.rdrop.com/~jimw
Computer Garage Fax - (503) 646-0174
><I have no idea, however, how you block and deblock I/O with 1K blocks when
><you have only 1k in your sector buffer. I suppose I could go back and loo
>
>You copy the sector to the 1k ram area and then copy out the desired
>sector. the real trick is keeping track of whats in ram and if it has
>to be written back.
I guess it's fortunate there was only one DMA process going on at the time,
else it might have been real sticky figuring out what had been overwritten
already.. If you were doing a read in order to do a write, using DMA, you
might actually get tangled up. Fortunately that showed up while the vendor
was debugging his code, so I didn't have to deal with that.
><at the software, but the stuff I had at my disposal at the time seemed to
><work best with a big hard disk requiring the largest available granules
><(allocation blocks) and since the logical drives were limited to 8MB and
>
>the largest allocation blocks are due to the need to store in ram on a bit
>per allocation block basis, a bit for every allocation block on the disk.
>for something like a 8mb disk using 4k blcks that would be 256 bytes!
That's quite so. Fortunately one wasn't required to load data at the
granule size, but rather at the sector size, so you could get by with a read
of a 1K sector. Of course you had to read it before you could write it, so
you had to wait for the next revolution of the disk. All this went by so
fast, and, since I didn't run big databases requiring sorts to and from
disk, I didn't perceive much delay, as it only takes a few revolutions to
load up a program. So each drive had six logical drives on it.
><since CP/M was pretty much a thing of the past, I didn't see any point in
><wasting time and resources fine-tuning it. I used it because I had a few
><already-paid for cross assemblers and other tools for CP/M. Once a decent
><version of the PC-DOS became available, I was sure to make the switch. O
><course I didn't realize how long that would be. Nonetheless, once I had a
><PC with a '186 processor, I could run the CPM emulator to use my tools and
><the more modern hardware to do my work, and the CPM became a relic.
>
>Shame. I still use it. And I'm still finding ways to tune it for even
>more performance. It was the active full time OS amd machine until
>89 when I went pdp-11. After that it was the part time on line system.
>
>Current project is to add heirarchal directories (not the ZCPR user thing).
>it turns out to be doable though the bdos will have to be altered.
This all sounds like it could be fun if, for example, you're running it all
on classic and unmodified hardware. I'm not sure I'd want to try to earn my
living that way, though.
>Allison
>
Sellam Ismail <dastar(a)ncal.verio.com> wrote:
> Does anyone know what the function of an IBM 557 Alphabetic Interpreter
> is/was?
Yeah, it "interprets" punched cards, meaning it reads the punches and
prints human-readable characters, probably across the 12-edge.
"Alphabetic" probably means "can do letters too" (in addition to
0-9).
I vaguely remember one that used to sit in the University
of Maryland College Park Computer Science Center dispatch room,
as I recall it would print sixty-mumble characters across the
the 12-edge and put the next eleventy-so off to the right
about where the 12-punches would be.
-Frank McConnell
Hi everybody-
First off my e-mail address changed. I used to be rws(a)ais.net, now it's
rws(a)enteract.com.
Second, at the LAMARSfest yesterday at Grayslake IL (which was pretty
poor- a few expensive C=64's, lots of expensive PC clones, and not much
else), I got an Oneac ON! computer. (Actually somebody was holding a
"weird CP/M computer" for me there.) It's a black box about a foot square
by 3" tall, with no on/off switch, a huge capacitor inside across the
rectified mains to keep the switcher running for a while in case of power
failure, and serial console I/O. It has a ONFILE (basically a RAMdisk) of
2 MB, in 4256 DRAMs. A 5 1/4" DSQD floppy is permanently connected by
ribbon cable. It appears from the somewhat sketchy manual that it runs
ZCPR. Upon plugging it in and waiting 30 seconds, hitting CR gets a nice
main menu with choices of a (decent) monitor, initialize the ONFILE, run
Z-system, and a few other things. I can't get it to load from disk to
init the ONFILE yet but I didn't try very hard yet.
Has anyone even heard of this thing? It looks pretty neat. I hope I can
get it running.
Richard Schauer
rws(a)enteract.com
At 08:37 PM 3/29/99 -0800, you wrote:
>
>Does anyone know what the function of an IBM 557 Alphabetic Interpreter
>is/was?
>
>Looks like a punch card sorter of some sort.
Not quite... The 557 interpreter reads and prints the content of a card
back onto the card, in a format of up to 60 print columns and on one of 25
selectable horizontal positions.
Thie was a more advanced model that the previous 548 and 552 models, and
had more available options. Some of these included:
(quoted from "IBM Machine Operation and Wiring - 2nd edition")
* Repetitive print for printing on detail cards the information read from
an X or NX master
* Proof checking of interpreting and other functions
* A second print entry that will permit one control panel to handle two
lines or two jobs
* A pre-sensing (control-X reading) station for use in selecting alphabetic
information and also for use in the repetitive-print operation
* Large type wheels and check protection (for printing checks)
Up to four selective stackers
So, why? Did you find one???
-jim
---
jimw(a)agora.rdrop.com
The Computer Garage - http://www.rdrop.com/~jimw
Computer Garage Fax - (503) 646-0174
<I have no idea, however, how you block and deblock I/O with 1K blocks when
<you have only 1k in your sector buffer. I suppose I could go back and loo
You copy the sector to the 1k ram area and then copy out the desired
sector. the real trick is keeping track of whats in ram and if it has
to be written back.
<at the software, but the stuff I had at my disposal at the time seemed to
<work best with a big hard disk requiring the largest available granules
<(allocation blocks) and since the logical drives were limited to 8MB and
the largest allocation blocks are due to the need to store in ram on a bit
per allocation block basis, a bit for every allocation block on the disk.
for something like a 8mb disk using 4k blcks that would be 256 bytes!
<since CP/M was pretty much a thing of the past, I didn't see any point in
<wasting time and resources fine-tuning it. I used it because I had a few
<already-paid for cross assemblers and other tools for CP/M. Once a decent
<version of the PC-DOS became available, I was sure to make the switch. O
<course I didn't realize how long that would be. Nonetheless, once I had a
<PC with a '186 processor, I could run the CPM emulator to use my tools and
<the more modern hardware to do my work, and the CPM became a relic.
Shame. I still use it. And I'm still finding ways to tune it for even
more performance. It was the active full time OS amd machine until
89 when I went pdp-11. After that it was the part time on line system.
Current project is to add heirarchal directories (not the ZCPR user thing).
it turns out to be doable though the bdos will have to be altered.
Allison
<Teletype, so I'm pretty sure the Elf code is correct. I'm using 110
<bits per second, no parity, 8 data bits, one low (logic 0) start bit,
<and one high (logic 1) stop bit. It seems to like the data
TWO stop bits, tty did two. 8n2
<characters; I get consistent hex values for each character I send to the
<Elf, but they seem to usually be either shifted left or right by one
<bit, or they have the high bit set when it shouldn't be. It feels like
It may be the one stop bit missing or there are too many transistions going
on die to contact bounce (dirty commutator and poor signal conditioning on
the other end).
TTy reading 8 level tape is a continious stream of start, lsb...msb,stop
stop and repeat. the COSMAC in this case is just sitting there playing
catch. If the timing loop is off on the RX end you get garbage.
Allison
>Today I salvaged a very odd looking DEC box, and I have no idea what it
>is. It is in a black metal case, with vents at the top, the external
>ports look like those of a VT-100, it has Video in, Video Out, Comm, 20ma
>Current Loop, and keyboard. The model number is stamped 70-17562-01, but
>the Serial number is stamped N/A.
>
>Does anyone know what this is? I suspect it is some kind of terminal, but
>I'm not sure.
I think it is the VT100 portion of a VSV11... the output of the VT100
in that box could be fed through a signal cable to the VSV11, and thus
displayed...
(If you otherwise have no need for it, I have a VSV11 without that part).
Megan Gentry
Former RT-11 Developer
+--------------------------------+-------------------------------------+
| Megan Gentry, EMT/B, PP-ASEL | Internet (work): gentry!zk3.dec.com |
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