Re: Reading MT/ST tapes

[Len Shustek via cctalk]

Date: Wed, 28 Jul 2021 18:37:17 -0500
From: Cory Heisterkamp 
 This is a bit of a long shot, but is anyone aware of a successful 
method to read IBM Selectric MT/ST tapes?

 A museum in Australia has a box of them and are interested in the contents.


At the Computer History Museum we sometimes use a software technique 
to recover data from the analog waveforms on mag tapes.

https://github.com/LenShustek/readtape
I'd like to try that on MT/ST tapes. Does anyone have a couple of 
MT/ST tape cartridges with data that I can experiment with?

Re: Reading MT/ST Tapes

[jim stephens via cctalk]

On 7/31/2021 8:12 PM, Chuck Guzis via cctalk wrote:

On 7/31/21 6:23 PM, Steve Malikoff via cctalk wrote:


A practice still observable on Youtube where you can marvel at a grimy oily
ASR33 being stripped down and restored, all the while whilst wearing a spotless
crisp ironed long-sleeve pin-striped business shirt... :)
https://www.youtube.com/watch?v=pEzpYHb4p5w

Another one comes to mind--picking out bits of shredded ribbon from a
line printer type train.

--Chuck

A friend told me of  guy who prided him on the white shirt and tie sort 
of dress code
despite it being unnecessary at a place he worked.  People would just 
shake their

heads and just let it go.

One morning, a lady he worked with stopped him short of going into a 
room where
the printer were, and a burster.  "Johnny (or whatever)" is in there, 
you don't want

to go in.

He peeked in and a burster had shot carbon paper from about half a case 
of 4 ply

all over the room and he was having to pick up the mess.

thanks
Jim

Re: Reading MT/ST Tapes

[Chuck Guzis via cctalk]

On 7/31/21 6:23 PM, Steve Malikoff via cctalk wrote:

> A practice still observable on Youtube where you can marvel at a grimy oily
> ASR33 being stripped down and restored, all the while whilst wearing a 
> spotless
> crisp ironed long-sleeve pin-striped business shirt... :)
> https://www.youtube.com/watch?v=pEzpYHb4p5w

Another one comes to mind--picking out bits of shredded ribbon from a
line printer type train.

--Chuck

Re: Reading MT/ST Tapes

[Steve Malikoff via cctalk]

Paul said
>Part of the fun of the banking terminals was some bank branches had the
>machines on the counter, right where the banks customers are, and
>customers would often feel obliged to offer some of their wit or wisdom
>while you where up to you elbows in a greasy machine.  I those days of
>working on greasy mechanical machine we where obliged to wear suit and
>tie

A practice still observable on Youtube where you can marvel at a grimy oily
ASR33 being stripped down and restored, all the while whilst wearing a spotless
crisp ironed long-sleeve pin-striped business shirt... :)
https://www.youtube.com/watch?v=pEzpYHb4p5w

Steve

Re: Reading MT/ST Tapes

[Grant Taylor via cctalk]

On 7/31/21 1:38 PM, Chuck Guzis via cctalk wrote:

Typo--I don't see so well in the morning.  Obcously, S/360


ACK

I would have assumed a typo, but as I get deeper and deeper into IBM, 
I'm finding more and more System/### than I ever heard of.  So there was 
a non-trivial possibility that's what this was.




--
Grant. . . .
unix || die

Re: Reading MT/ST Tapes

[Chuck Guzis via cctalk]

On 7/31/21 10:40 AM, Paul Berger via cctalk wrote:

> I have never seen either of these machines but looking at pictures of
> them it looks like the first version of 1620 had a type bar typewriter
> as a console.  These type bar machine would have a common heritage with
> the Flexowriters both are descendants of the  Electromatic company that
> IBM purchased in 1932 but later sold off what became Flexowriter due to
> anti-trust concerns.

There were a *lot* more Model I 1620s in the wild (CADET) than Model IIs
(which apparently could add and subtract without being instructed how to
do it).

There's a photo of a Model II typewriter on PDF page 92 here:

http://www.bitsavers.org/pdf/ibm/1620/A26-5781-2_IBM_1620_CPU_Model_2_Nov65.pdf

Shame that the Model II wasn't more popular--IBM did a lot of things
right, including goodies like index registers.  I think I may have seen
only one Model II in the flesh--and I've never seen a 1620 with 729-II
tape drives attached, much less a tape written by a 1620.

The model I appeared to use a modified for use Model B electric:

https://www.ibm.com/ibm/history/exhibits/modelb/modelb_intro.html

For a couple of years, I used a Model B Executive with the split space
bar.  I had the best-looking memos in the department.

--Chuck

Re: Reading MT/ST Tapes

[Chuck Guzis via cctalk]

On 7/31/21 12:22 PM, Grant Taylor via cctalk wrote:
> On 7/31/21 10:19 AM, Chuck Guzis via cctalk wrote:
>> Did the 1620 Mod II and the 1130 use the same Selectric mechanism as
>> the S/260 1052?
> 
> Is the S/260 a system that I'm completely oblivious to?  Or is it a typo?

Typo--I don't see so well in the morning.  Obcously, S/360

Re: Reading MT/ST Tapes

[Grant Taylor via cctalk]

On 7/31/21 10:19 AM, Chuck Guzis via cctalk wrote:
Did the 1620 Mod II and the 1130 use the same Selectric mechanism as 
the S/260 1052?


Is the S/260 a system that I'm completely oblivious to?  Or is it a typo?



--
Grant. . . .
unix || die

Re: Reading MT/ST Tapes

[Paul Berger via cctalk]

On 2021-07-31 1:19 p.m., Chuck Guzis via cctalk wrote:

On 7/31/21 8:55 AM, Paul Berger via cctalk wrote:


Since there was still a few 360s around when I started I also got to see
the inside of a 1052 a few times, they are a really stripped down
keyboardless selectric.  They used a function cam to space and since
they did not have a tab rack they would space a lot which would cause
the space cam to wear, I remember one that was so worn  that when it
cycled it wobbled very noticeably, the customer would not let us replace
it as this was the console for the 360 and they did not want it
unavailable for the time it would take to replace it.  Some customers
apparently would have a spare 1052 onsite.  The keyboard on the 1052 is
the keyboard from a keypunch machine.

Did the 1620 Mod II and the 1130 use the same Selectric mechanism as the
S/260 1052?  I remember that the Model B on the CADET always felt as if
it would shake itself to pieces every time the carriage returned.

And given the relatively high failure rate for motor drive belts, why
did IBM persist in making replacement such a bugger of a job?

--Chuck

I have never seen either of these machines but looking at pictures of 
them it looks like the first version of 1620 had a type bar typewriter 
as a console.  These type bar machine would have a common heritage with 
the Flexowriters both are descendants of the  Electromatic company that 
IBM purchased in 1932 but later sold off what became Flexowriter due to 
anti-trust concerns.


I did find a picture of a 1620 that does appear to have a selectric for 
a console and it looks like it is a modified OP selectric even being in 
the same case sunk into the desk so I suspect that it is the first 
version of the selectric I/O.


The console on the 1130 does however look like it is a 1052 that has 
been integrated into the machine.


Speaking of shaking apart on carriage return, I was once preparing some 
cash registers for the local phone company in a room where the had a HP 
mini that apparent ran some terminals for their subsidiary phone company 
in Prince Edward Island.  This HP had an ASR-33 for a console and it 
seemed that it printed a line for every transaction and when it would 
return it would slam into the dashpot on the left frame and the whole 
ASR-33 would rock. This mini recorded transactions on punched tape that 
was taken downstairs to the main computer room where it was read into 
the IBM mainframe on a high speed punched tape reader that looked like a 
3430  tape drive with the magnet head replaced by an optical head.


With regard to the position of the belt it is where it is because the 
selectric mechanism is split into two parts. On the left is the cycle 
shaft with the cams that position the type ball and through some gears 
turns the print shaft that drives the ball into the paper.  right in the 
middle running inside the appropriately named center bearing, is the hub 
that has the pulley on it that is driven by the motor this turn 
constantly.  on the left side of the the hub there is a torrington 
clutch  that when tripped turns the cycle shaft to print a character.  
On the right side of the hub is the operational shaft that turns all the 
time that have clutched cams on it to operate functions such as tab and 
backspace, plus another torrington clutch for carriage return, and on 
the extreme right a cam for shift that rotate the ball 180 degrees.  It 
would seem that the motor belt is positioned where it is so that the 
entire machine could be operated from a single motor.


On OP selectrics changing the belt is not such a big deal, you take out 
one of the gears that drives print shaft, remove the screws that hold 
the bearing plate on the left end of the cycle shaft and the either back 
off or remove entirely the cycle shaft. It was more of a challenge on 
the original I/O because of the presence of contact block both at the 
end of the cycle shaft and under the selection latches.  The original 
I/O was just a modified OP selectric That other than the addition of the 
contacts and magnets the only other change was the beefier capacitive 
start motor, I have seen this motor tear the teeth off a belt on a 
jammed machine just by turning it on.  You did not even have to look to 
tell if a belt was missing teeth, they had a telltale thumping noise you 
could hear as soon as you got close to it.


The I/O II was a lot better changing belts was pretty much the same  as 
an OP selectric and I don't recall having to change them as often.  The 
worst where the machines that where in a case like an OP selectric sunk 
into a desk, that case and mount just made things more difficult.


Part of the fun of the banking terminals was some bank branches had the 
machines on the counter, right where the banks customers are, and 
customers would often feel obliged to offer some of their wit or wisdom 
while you where up to you elbows in a greasy machine.  I those days of 
working on greasy 

Re: Reading MT/ST Tapes

[Guy Sotomayor via cctalk]

On 7/31/21 9:19 AM, Chuck Guzis via cctalk wrote:

On 7/31/21 8:55 AM, Paul Berger via cctalk wrote:


Since there was still a few 360s around when I started I also got to see
the inside of a 1052 a few times, they are a really stripped down
keyboardless selectric.  They used a function cam to space and since
they did not have a tab rack they would space a lot which would cause
the space cam to wear, I remember one that was so worn  that when it
cycled it wobbled very noticeably, the customer would not let us replace
it as this was the console for the 360 and they did not want it
unavailable for the time it would take to replace it.  Some customers
apparently would have a spare 1052 onsite.  The keyboard on the 1052 is
the keyboard from a keypunch machine.

Did the 1620 Mod II and the 1130 use the same Selectric mechanism as the
S/260 1052?  I remember that the Model B on the CADET always felt as if
it would shake itself to pieces every time the carriage returned.


I was "loaned" a 1052 when I was in college and it was built like a 
tank.  Much heavier than typical selectrics from what I could tell.


I built my own 48v drivers to run it and wrote  bunch of code (8080/z80) 
to run it as an ASCII terminal (yea, I know). Unfortunately, I've lost 
all of it in various moves/purges.


--
TTFN - Guy

Re: Reading MT/ST Tapes

[Chuck Guzis via cctalk]

On 7/31/21 8:55 AM, Paul Berger via cctalk wrote:

> Since there was still a few 360s around when I started I also got to see
> the inside of a 1052 a few times, they are a really stripped down
> keyboardless selectric.  They used a function cam to space and since
> they did not have a tab rack they would space a lot which would cause
> the space cam to wear, I remember one that was so worn  that when it
> cycled it wobbled very noticeably, the customer would not let us replace
> it as this was the console for the 360 and they did not want it
> unavailable for the time it would take to replace it.  Some customers
> apparently would have a spare 1052 onsite.  The keyboard on the 1052 is
> the keyboard from a keypunch machine.

Did the 1620 Mod II and the 1130 use the same Selectric mechanism as the
S/260 1052?  I remember that the Model B on the CADET always felt as if
it would shake itself to pieces every time the carriage returned.

And given the relatively high failure rate for motor drive belts, why
did IBM persist in making replacement such a bugger of a job?

--Chuck

Re: Reading MT/ST Tapes

[Paul Berger via cctalk]

On 2021-07-30 11:34 p.m., Chuck Guzis via cctalk wrote:

On 7/30/21 6:22 PM, Paul Berger via cctalk wrote:


The MT/ST did pretty good for being a electro-mechanical device,all the
logic was relays in it.  I seem to recall many years ago one of the old
OP guys telling me that it write in stripes across the tape. It would
have to be some very simple format because it would be hard to have the
thing sync on headers with only a little relay logic.

Like a motion picture film projector.  Brings the tape to a complete
stop for each character and then scans across it with a single head;
going in, the character is read, going out, the character just read is
checked.  I assume (but am not sure) that if the check fails, a retry is
attempted.  The head moves at 45 ips and records bits at a 45 degree
angle relative to the tape axis.   This is so the tape can be scanned
without moving the head for a mark in the control track (reading
parallel to the axis of tape movement) or reading characters with the
tape stopped (reading orthogonal to the tape movement.  Obviously,
precise tape positioning is important (even at 20 cpi), hence the
sprocket feed.

In off-list conversations with others, I keep trying to impress on the
younger folks that this is basically an electro-mechanical device with
heavy emphasis on mechanics.  After all, the people who serviced these
things were typewriter repair people.  I doubt that the innards of the
MT/ST were much more complex than those of the Selectric itself. (One of
these days, I'll get up the nerve to replace the motor drive belt in my
Correcting Selectric III).

But when you've grown up with microprocessors, I guess it can be hard to
envision a world with only rudimentary electronics.

--Chuck


I changed lots of motor belts when I first started as a CE, but not on 
OP selectrics but on selectric terminals.  The OP selectric used a 
relatively weak motor that would stall if the mechanism jammed, but the 
terminals used a stronger capacitor start motor that when the mechanism 
jammed  it would either break the belt or tear the teeth off it at the 
motor pulley.  Changing the belts on the terminals was even more fun 
because of all the added contact blocks to make it function as a terminal.


The ones I spent the most time one the first few years where banking 
terminals the control for them was electronic, low density probably on 
the scale of early 360 computers, and was very solid so all of the time 
was spent fixing mechanical issues with the selectric. It was not helped 
by these terminals having a small core buffer so messages would be 
buffered by the control unit and then printed on the selectric as fast 
as the mechanism would go which contributed to wear.  The selectrics on 
these terminals where just standard OP selectrics with solenoids 
(magnets) and contacts hung on them to make them work as an I/O.  I 
suspect the MT/ST had a similar typer on them and I feel for the guys 
who had to maintain them because I am sure MT/ST customers when a lot 
more picky about print quality that terminal customers, and then there 
was the composer version of the MT/ST, I am told that composer customer 
where super picky about print quality.


It seems to me that the mag card machines had a version of selectric I/O 
that was designed as an I/O unit with key parts of the mechanism beefed 
up to improve reliability.  Some of the selectric terminals I worked on 
had a similar mechanism that separated the keyboard from the printer, it 
was still a standard selectric keyboard but the printer did not take a 
cycle when  a key was pressed.  The open transfer contacts where 
replaced by reed switches and magnets so they did not get fouled by oil 
and grease like the open contacts.


Since there was still a few 360s around when I started I also got to see 
the inside of a 1052 a few times, they are a really stripped down 
keyboardless selectric.  They used a function cam to space and since 
they did not have a tab rack they would space a lot which would cause 
the space cam to wear, I remember one that was so worn  that when it 
cycled it wobbled very noticeably, the customer would not let us replace 
it as this was the console for the 360 and they did not want it 
unavailable for the time it would take to replace it.  Some customers 
apparently would have a spare 1052 onsite.  The keyboard on the 1052 is 
the keyboard from a keypunch machine.


So yes even though I started in 1979 there was still a requirement for 
having good mechanical skill as well as knowing electronics to fix DP 
equipment, even for the guys looking after mainframes and associated 
I/O.  Card equipment was still common and the most common printer was 
1403 with it hydraulic paper feed.  3890 cheque sorters arrived around 
the same time and the mechanics of them was pretty maintenance intensive.


Paul.

Re: Reading MT/ST Tapes

[Chuck Guzis via cctalk]

On 7/30/21 6:22 PM, Paul Berger via cctalk wrote:

> The MT/ST did pretty good for being a electro-mechanical device,all the
> logic was relays in it.  I seem to recall many years ago one of the old
> OP guys telling me that it write in stripes across the tape. It would
> have to be some very simple format because it would be hard to have the
> thing sync on headers with only a little relay logic.

Like a motion picture film projector.  Brings the tape to a complete
stop for each character and then scans across it with a single head;
going in, the character is read, going out, the character just read is
checked.  I assume (but am not sure) that if the check fails, a retry is
attempted.  The head moves at 45 ips and records bits at a 45 degree
angle relative to the tape axis.   This is so the tape can be scanned
without moving the head for a mark in the control track (reading
parallel to the axis of tape movement) or reading characters with the
tape stopped (reading orthogonal to the tape movement.  Obviously,
precise tape positioning is important (even at 20 cpi), hence the
sprocket feed.

In off-list conversations with others, I keep trying to impress on the
younger folks that this is basically an electro-mechanical device with
heavy emphasis on mechanics.  After all, the people who serviced these
things were typewriter repair people.  I doubt that the innards of the
MT/ST were much more complex than those of the Selectric itself. (One of
these days, I'll get up the nerve to replace the motor drive belt in my
Correcting Selectric III).

But when you've grown up with microprocessors, I guess it can be hard to
envision a world with only rudimentary electronics.

--Chuck

Re: Reading MT/ST Tapes

[Fred Cisin via cctalk]

I would think that an engineer would realize that the glass is neither 
half-full NOR half-empty; it is merely that the glass was spec'ed with the 
wrong size.



Yes, I am too cynical to be in marketing.


On Fri, 30 Jul 2021, Mike Stein wrote:


And here I've always thought of you as a pessimist who would have called it
'Half Empty ST'...

On Fri, Jul 30, 2021 at 9:17 PM Fred Cisin via cctalk 
wrote:


Yep.

And, it was not appreciated when I suggested an interim release between
the MT/ST emulator and "Full-ST" to be called "Half Full ST"


On Fri, 30 Jul 2021, grif...@mindspring.com wrote:


Scope Creep.. no telling how many projects died in stalled development.

On Jul 30, 2021 16:36, Fred Cisin via cctalk 
wrote:

  On Fri, 30 Jul 2021, Chuck Guzis via cctalk wrote:
 > Not really--it's very old technology, (1964), of limited
  capacity (about
 > 20 KB per tape), was a hideously expensive way to buy a
  typewriter
 > (about USD$7000 in 1964, or about USD$61,000 today), used
  almost
 > exclusively in large corporate offices to create form
  letters and
 > documents.  In other words, it was not intended as an
  archival medium.
 > The effort required in preparing a document was
  considerable (one used
 > the mini-keypad for various functions).  For a memo, it was
  easiest to
 > use the typewriter as a typewriter.
 > There are more interesting things to look at.

  Well, form letters are "important".
  But, once microcomputer word processing matured, they could
  be done easily
  and much better.

  An acquaintance was working on creating an emulation of the
  MT/ST, as a
  way for those who were familiar with the MT/ST and/or
  actually liked it,
  to be able to continue unchanged on a microcomputer.

  But, then he started adding features.  Besides delaying the
  completion
  until it was no longer relevant, it was suggested that he
  change the name
  from "MT/ST" (pronounced "empty ST") to "FULL ST".

Re: Reading MT/ST Tapes

[Mike Stein via cctalk]

And here I've always thought of you as a pessimist who would have called it
'Half Empty ST'...

On Fri, Jul 30, 2021 at 9:17 PM Fred Cisin via cctalk 
wrote:

> Yep.
>
> And, it was not appreciated when I suggested an interim release between
> the MT/ST emulator and "Full-ST" to be called "Half Full ST"
>
>
> On Fri, 30 Jul 2021, grif...@mindspring.com wrote:
>
> > Scope Creep.. no telling how many projects died in stalled development.
> >
> > On Jul 30, 2021 16:36, Fred Cisin via cctalk 
> > wrote:
> >
> >   On Fri, 30 Jul 2021, Chuck Guzis via cctalk wrote:
> >   > Not really--it's very old technology, (1964), of limited
> >   capacity (about
> >   > 20 KB per tape), was a hideously expensive way to buy a
> >   typewriter
> >   > (about USD$7000 in 1964, or about USD$61,000 today), used
> >   almost
> >   > exclusively in large corporate offices to create form
> >   letters and
> >   > documents.  In other words, it was not intended as an
> >   archival medium.
> >   > The effort required in preparing a document was
> >   considerable (one used
> >   > the mini-keypad for various functions).  For a memo, it was
> >   easiest to
> >   > use the typewriter as a typewriter.
> >   > There are more interesting things to look at.
> >
> >   Well, form letters are "important".
> >   But, once microcomputer word processing matured, they could
> >   be done easily
> >   and much better.
> >
> >   An acquaintance was working on creating an emulation of the
> >   MT/ST, as a
> >   way for those who were familiar with the MT/ST and/or
> >   actually liked it,
> >   to be able to continue unchanged on a microcomputer.
> >
> >   But, then he started adding features.  Besides delaying the
> >   completion
> >   until it was no longer relevant, it was suggested that he
> >   change the name
> >   from "MT/ST" (pronounced "empty ST") to "FULL ST".
>

Re: Reading MT/ST Tapes

[Paul Berger via cctalk]

On 2021-07-30 9:39 p.m., Chuck Guzis via cctalk wrote:


One of the shortcomings of the MT/ST when compared to word processors is
the lack of a good "mailmerge" option.   You could code a stop code on
the tape, where the typewriter would allow for manual fill-in-the-blanks
operation, but that gets pretty cumbersome when dealing with hundreds of
copies.

Superseded by the MC/ST system, the "mag card" Selectric in 1969.  Far
more convenient and better integrated into the typewriter itself (no
separate keypad).  The MC/ST II in 1973 introduced the ability to
"batch" up to 50 cards.

Here's a promo film from the period, narrated by the guy driving his
road yacht with the AM radio and chatting about it.

https://youtu.be/bW_jJjUarp0

--Chuck

The MT/ST did pretty good for being a electro-mechanical device,all the 
logic was relays in it.  I seem to recall many years ago one of the old 
OP guys telling me that it write in stripes across the tape. It would 
have to be some very simple format because it would be hard to have the 
thing sync on headers with only a little relay logic.


The mag card machines had the advantage of by the time it came along 
electronics was a lot more compact so they could stuff a much more 
capable controller in the box.  Towards the end of the mag card days 
there was even a machine that had a daisy wheel typewriter on it.


Paul.

Re: Reading MT/ST Tapes

[Fred Cisin via cctalk]

Yep.

And, it was not appreciated when I suggested an interim release between 
the MT/ST emulator and "Full-ST" to be called "Half Full ST"



On Fri, 30 Jul 2021, grif...@mindspring.com wrote:


Scope Creep.. no telling how many projects died in stalled development.

On Jul 30, 2021 16:36, Fred Cisin via cctalk 
wrote:

  On Fri, 30 Jul 2021, Chuck Guzis via cctalk wrote:
  > Not really--it's very old technology, (1964), of limited
  capacity (about
  > 20 KB per tape), was a hideously expensive way to buy a
  typewriter
  > (about USD$7000 in 1964, or about USD$61,000 today), used
  almost
  > exclusively in large corporate offices to create form
  letters and
  > documents.  In other words, it was not intended as an
  archival medium.
  > The effort required in preparing a document was
  considerable (one used
  > the mini-keypad for various functions).  For a memo, it was
  easiest to
  > use the typewriter as a typewriter.
  > There are more interesting things to look at.

  Well, form letters are "important".
  But, once microcomputer word processing matured, they could
  be done easily
  and much better.

  An acquaintance was working on creating an emulation of the
  MT/ST, as a
  way for those who were familiar with the MT/ST and/or
  actually liked it,
  to be able to continue unchanged on a microcomputer.

  But, then he started adding features.  Besides delaying the
  completion
  until it was no longer relevant, it was suggested that he
  change the name
  from "MT/ST" (pronounced "empty ST") to "FULL ST".

Re: Reading MT/ST Tapes

[Chuck Guzis via cctalk]

On 7/30/21 4:36 PM, Fred Cisin via cctalk wrote:

> Well, form letters are "important".
> But, once microcomputer word processing matured, they could be done
> easily and much better.
> 
> An acquaintance was working on creating an emulation of the MT/ST, as a
> way for those who were familiar with the MT/ST and/or actually liked it,
> to be able to continue unchanged on a microcomputer.
> 
> But, then he started adding features.  Besides delaying the completion
> until it was no longer relevant, it was suggested that he change the
> name from "MT/ST" (pronounced "empty ST") to "FULL ST".

One of the shortcomings of the MT/ST when compared to word processors is
the lack of a good "mailmerge" option.   You could code a stop code on
the tape, where the typewriter would allow for manual fill-in-the-blanks
operation, but that gets pretty cumbersome when dealing with hundreds of
copies.

Superseded by the MC/ST system, the "mag card" Selectric in 1969.  Far
more convenient and better integrated into the typewriter itself (no
separate keypad).  The MC/ST II in 1973 introduced the ability to
"batch" up to 50 cards.

Here's a promo film from the period, narrated by the guy driving his
road yacht with the AM radio and chatting about it.

https://youtu.be/bW_jJjUarp0

--Chuck

Re: Reading MT/ST Tapes

[Fred Cisin via cctalk]

On Fri, 30 Jul 2021, Chuck Guzis via cctalk wrote:

Not really--it's very old technology, (1964), of limited capacity (about
20 KB per tape), was a hideously expensive way to buy a typewriter
(about USD$7000 in 1964, or about USD$61,000 today), used almost
exclusively in large corporate offices to create form letters and
documents.  In other words, it was not intended as an archival medium.
The effort required in preparing a document was considerable (one used
the mini-keypad for various functions).  For a memo, it was easiest to
use the typewriter as a typewriter.
There are more interesting things to look at.


Well, form letters are "important".
But, once microcomputer word processing matured, they could be done easily 
and much better.


An acquaintance was working on creating an emulation of the MT/ST, as a 
way for those who were familiar with the MT/ST and/or actually liked it, 
to be able to continue unchanged on a microcomputer.


But, then he started adding features.  Besides delaying the completion 
until it was no longer relevant, it was suggested that he change the name 
from "MT/ST" (pronounced "empty ST") to "FULL ST".

Re: Reading MT/ST Tapes

[Chuck Guzis via cctalk]

On 7/30/21 3:56 PM, Cory Heisterkamp via cctalk wrote:

> With all of the pet projects documented on the net (ranging from the esoteric 
> to the absurd) it’s interesting that no one has tackled this one yet. -C

Not really--it's very old technology, (1964), of limited capacity (about
20 KB per tape), was a hideously expensive way to buy a typewriter
(about USD$7000 in 1964, or about USD$61,000 today), used almost
exclusively in large corporate offices to create form letters and
documents.  In other words, it was not intended as an archival medium.

The effort required in preparing a document was considerable (one used
the mini-keypad for various functions).  For a memo, it was easiest to
use the typewriter as a typewriter.

There are more interesting things to look at.

--Chuck

Re: Reading MT/ST Tapes

[Cory Heisterkamp via cctalk]

> On Jul 29, 2021, at 12:46 PM, Chuck Guzis via cctalk  
> wrote:
> 
> A link I forgot to include that gives a flavor of how the tapes are used:
> 
> https://files.eric.ed.gov/fulltext/ED112083.pdf
> 
> Curious thing is that was no take-up reel on the MT/ST; the 100 feet of
> tape simply was ejected loose and later rewound back into the cartridge.
> 
> 
> --Chuck

All, thanks for the references and background. I guess the first hurdle for the 
library is if there’s even data present. I passed on the suggestion of liquid 
mag developer as something “easy” to try. 

With all of the pet projects documented on the net (ranging from the esoteric 
to the absurd) it’s interesting that no one has tackled this one yet. -C

Re: Reading MT/ST Tapes

[Chuck Guzis via cctalk]

A link I forgot to include that gives a flavor of how the tapes are used:

https://files.eric.ed.gov/fulltext/ED112083.pdf

Curious thing is that was no take-up reel on the MT/ST; the 100 feet of
tape simply was ejected loose and later rewound back into the cartridge.


--Chuck

Re: Reading MT/ST Tapes

[Chuck Guzis via cctalk]

Here's the MT/ST typewriter setup

https://britishlibrary.typepad.co.uk/.a/6a00d8341c464853ef01901bc4e1f6970b-500wi

Here's a brochure for the S/360 reader:

http://ed-thelen.org/comp-hist/IBM-ProdAnn/2495-5.pdf

Here's a training guide for the MT/ST:

https://ia800805.us.archive.org/26/items/IBM-MTSC-TrainingGuide/IBM%20Magnetic%20Tape%20Selectric%20Composer%20training%20guide.pdf

FWIW
Chuck

Re: Reading MT/ST Tapes

[Al Kossow via cctalk]

On 7/29/21 7:21 AM, Chuck Guzis via cctalk wrote:


The hard part is going to find one of the reader units.



Digi-Data made them
https://www.computerhistory.org/collections/catalog/102662523

Sadly, whoever cataloged this had no idea it was for IBM MT/ST tapes
so there is no mention of MT/ST in the catalog record so I had to
search every physical object record I donated to find it.

Re: Reading MT/ST Tapes

[Chuck Guzis via cctalk]

On 7/29/21 1:58 AM, Dave Wade G4UGM via cctalk wrote:

> Its only recorded at around 25BPI so I don't thing it would be too hard to 
> decode.
> Given its a character at a time, I suspect some iron filings or similar would 
> reveal the codes and track spacing and with a bit of luck you could find a 
> head that would read the data...
> I am sure we used to have some when we had real tapes.

The second inquiry for me in about 30 years.

I've occasionally seen the tape units come up for auction, but not in
the last 10 years or so.   There was even a version to interface to a
S/360 channel.

There is documentation on the stuff running around; it may have been
from the old golfballtypewritershop yahoo group.  Someone from the
https://groups.io/g/TYPEWRITERS may have a lead on a unit or at least
memories of it.

The hard part is going to find one of the reader units.

--Chuck

Re: Reading MT/ST Tapes

[Paul Koning via cctalk]

One of those magnetic fluid tape checking devices would show the bits very 
easily at that density (or even a lot higher).  

It seems to me this sort of thing should be no problem at all for the various 
general purpose tape reading machines that have been built, especially the ones 
with MR heads.  So long as the reader has heads that land reasonably well on 
the recorded tracks, the rest is just software.

Part of the software work would be reverse engineering the recording format -- 
NRZ or NRZI or whatever, bit layout and character set encoding, file encoding.  
The encoding of formatting control information will probably be guesswork, but 
recovering most of the plain text should be doable.

paul

> On Jul 29, 2021, at 4:58 AM, Dave Wade G4UGM via cctalk 
>  wrote:
> 
> Cory,
> 
> Its only recorded at around 25BPI so I don't thing it would be too hard to 
> decode.
> Given its a character at a time, I suspect some iron filings or similar would 
> reveal the codes and track spacing and with a bit of luck you could find a 
> head that would read the data...
> I am sure we used to have some when we had real tapes.
> 
> Dave
> 
> 
>> -Original Message-
>> From: cctalk  On Behalf Of Cory
>> Heisterkamp via cctalk
>> Sent: 29 July 2021 00:37
>> To: General Discussion: On-Topic Posts 
>> Subject: Reading MT/ST Tapes
>> 
>> This is a bit of a long shot, but is anyone aware of a successful method to 
>> read
>> IBM Selectric MT/ST tapes? A museum in Australia has a box of them and are
>> interested in the contents.
>> 
>> I'm fairly involved in the global Selectric community and while 1 or 2 
>> MT/ST’s
>> exist, they’re non-functional. I know IBM offered a 2495 Tape Reader for the
>> IBM 360, which could be a starting point with modification, but I suspect
>> those are even scarcer than the MT/ST itself.
>> 
>> Even the encoding format appears to be a bit of a secret. Recording is
>> character-by-character, tape spacing controlled by sprocket holes along one
>> edge.
>> 
>> https://obsoletemedia.org/ibm-mtst/ > mtst/?fbclid=IwAR28c5ej69AlF0os1PcykpHCh0Q_yz5BXbnUSi9UID-
>> 4pY6GU3wLxZXFhDI>
>> 
>> Thanks- Cory
> 

RE: Reading MT/ST Tapes

[Dave Wade G4UGM via cctalk]

Cory,

Its only recorded at around 25BPI so I don't thing it would be too hard to 
decode.
Given its a character at a time, I suspect some iron filings or similar would 
reveal the codes and track spacing and with a bit of luck you could find a head 
that would read the data...
I am sure we used to have some when we had real tapes.

Dave


> -Original Message-
> From: cctalk  On Behalf Of Cory
> Heisterkamp via cctalk
> Sent: 29 July 2021 00:37
> To: General Discussion: On-Topic Posts 
> Subject: Reading MT/ST Tapes
> 
> This is a bit of a long shot, but is anyone aware of a successful method to 
> read
> IBM Selectric MT/ST tapes? A museum in Australia has a box of them and are
> interested in the contents.
> 
> I'm fairly involved in the global Selectric community and while 1 or 2 MT/ST’s
> exist, they’re non-functional. I know IBM offered a 2495 Tape Reader for the
> IBM 360, which could be a starting point with modification, but I suspect
> those are even scarcer than the MT/ST itself.
> 
> Even the encoding format appears to be a bit of a secret. Recording is
> character-by-character, tape spacing controlled by sprocket holes along one
> edge.
> 
> https://obsoletemedia.org/ibm-mtst/  mtst/?fbclid=IwAR28c5ej69AlF0os1PcykpHCh0Q_yz5BXbnUSi9UID-
> 4pY6GU3wLxZXFhDI>
> 
> Thanks- Cory