Card Columns (was Why did they make ... ?) 
Author Message
 Card Columns (was Why did they make ... ?)



Quote:
>the tape controller

Which tape controller? The 729[1] was not the only tape drive. Of
course, for people on a normal budget it was, except for a few who
didn't even need the performance of the 729.

[1] Lumping all three models together in contrast to 7340.

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Tue, 26 Jul 2005 23:08:16 GMT  
 Card Columns (was Why did they make ... ?)


Quote:
>Did this machine not use the same card codes as the 1401 and
>System/360?  In which case, "A" is 12-1; 12-9 is "I".

Correct; he's also got the order wrong. I'm glad to see that I'm not
the only one that has to go back to the manual to get the details of
7090 I/O right. ;-) Both the reader and the punch start with 9-row
left.

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Tue, 26 Jul 2005 23:03:56 GMT  
 Card Columns (was Why did they make ... ?)


Quote:
>The most advanced of these machines, devices such as the 407

You're forgetting the CPC.

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Tue, 26 Jul 2005 22:53:53 GMT  
 Card Columns (was Why did they make ... ?)



Quote:


> >the tape controller

> Which tape controller? The 729[1] was not the only tape drive.
Of
> course, for people on a normal budget it was, except for a few
who
> didn't even need the performance of the 729.

> [1] Lumping all three models together in contrast to 7340.

I'd have to say I don't actually know. I didn't have the same
intimate knowledge of the various boxes on the floor of a 709x
system as I did for the 360s. My only experience with a 7094 was
as a student at the University of Maryland. Then, I only had a
copy of the PoO (which I may still have somewhere). I never
actually touched the machine.

However, I did see a lot of 729's, and I know that any
character-code translation had to take place outside of the
tape-drive itself. So, I assume it was done in the control
unit -- which I believe was called a Tape Adapter Unit (TAU) in
that generation, or it may have even been done in the Data
Channel circuitry. That I couldn't say.  I would imagine that the
TAU would probably have been the same, or similar, for most tape
drives.

In the case of the 360s, of course, the tape drive equivalent to
the 729 was known generically as the 2400-series. There were,
initially, three models, rated at different tape speeds, from
something like 35 IPS up to 117 IPS (IIRC). These models were
packaged into three forms: The 2401, a single tape drive in its
own box; the 2402, a double-drive box (never very popular); the
2403, a tape drive and tape controller (TAU) in one box, and the
2404, a "simultaneous read-write" controller, with dual channel
attachment, in one box. If you liked your tape controllers
stand-alone, those were the 2803 and 2804.

All these boxes I worked on extensively during my years as a CE,
as well as the occasional 729. These were pretty similar under
the skin, especially the engineering revision level known as
"Nor-Lay" (combination of SMS logic and relays for motion
control). For some reason, 729s always seemed dirtier inside. Go
figure.



Wed, 27 Jul 2005 05:49:05 GMT  
 Card Columns (was Why did they make ... ?)


Quote:
>My only experience with a 7094 was
>as a student at the University of Maryland.

I'd guess 729; how many universities could afford Hypertape?

BTW, on major difference between the 729 and 24xx tape drives was in
the mechanics. The 729 lifted the heads when it unloaded a tape. There
was an interlock to prevent the head from descending until the next
reel was mounted. One of our operators got his hand injured when the
interlock failed, and we kidded him about it for the next few weeks.

--
     Shmuel (Seymour J.) Metz, SysProg and JOAT

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action.  I reserve the right to publicly post or ridicule any
abusive E-mail.

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Fri, 29 Jul 2005 02:26:35 GMT  
 Card Columns (was Why did they make ... ?)




Quote:


> >My only experience with a 7094 was
> >as a student at the University of Maryland.

> I'd guess 729; how many universities could afford Hypertape?

Not many, I only saw such a drive in pictures.

Quote:

> BTW, on major difference between the 729 and 24xx tape drives
was in
> the mechanics. The 729 lifted the heads when it unloaded a
tape. There
> was an interlock to prevent the head from descending until the
next
> reel was mounted. One of our operators got his hand injured
when the
> interlock failed, and we kidded him about it for the next few

weeks.

You may be thinking of the later M/T 2420, not the 2401, which
was mechanically almost identical to a late-model 729. It also
raised the head cover just like the 729. It didn't actually raise
the head, as such, as the head was the lower part of the
assembly, just the tape-guide assembly.  It could still pinch if
you had your fingers in there when you started a Load/Rewind
sequence.

As far as interlocks are concerned, you may recall that the 729
had a window that had to be raised manually. There was an
interlock switch at the top.  On the 2401, the window was
electrically-operated, and the interlock was probably a bit more
reliable.  In any case, the idea was that you couldn't load a
tape with the window open. Very early 2401's didn't have the
electric windows. The windows were fixed, and the operator had to
swing open the full-length door on the drive -- a very awkward
move, if you were mounting tapes down a row of drives. The
electric windows were much more popular with operators.

For both machines, however, there was a mechanism to override the
interlock. On the 2401, it was by pulling out on the interlock
pin. I don't recall whether that same mechanism was used on the
729 or not.  This allowed the drive to be operated with the door
open, so that adjustments to prolays and such could be done by a
CE. Anyone else foolish enough to override the interlock got what
he deserved, IMO.

Although I never worked with 729s attached to 709x machines, I
worked on a good number attached to other 7xxx and 14xx systems.



Sat, 30 Jul 2005 07:24:15 GMT  
 Card Columns (was Why did they make ... ?)


Quote:
> On the 2401, the window was
> electrically-operated, and the interlock was probably a bit more
> reliable. <SNIP>
> The
> electric windows were much more popular with operators.

As I recall, this was not nearly as "popular with operators" as sitting the
mini-skirted junior op on top of the line printer and pressing the button to
raise the lid.
Sadly I dont recall the model numbers of the printer or the girl .
Sorry to break your train of thought... couldn't resist ;-)


Mon, 01 Aug 2005 08:23:52 GMT  
 Card Columns (was Why did they make ... ?)

Quote:



>>On the 2401, the window was
>>electrically-operated, and the interlock was probably a bit more
>>reliable. <SNIP>
>>The
>>electric windows were much more popular with operators.

> As I recall, this was not nearly as "popular with operators" as sitting the
> mini-skirted junior op on top of the line printer and pressing the button to
> raise the lid.
> Sadly I dont recall the model numbers of the printer or the girl .
> Sorry to break your train of thought... couldn't resist ;-)

1403-N1 (approximately 1965-1979).
3211 (approximately 1970-1980)

--
John W. Kennedy
"The poor have sometimes objected to being governed badly;
the rich have always objected to being governed at all."
   -- G. K. Chesterton, "The Man Who Was Thursday"



Mon, 01 Aug 2005 09:35:18 GMT  
 Card Columns (was Why did they make ... ?)

Quote:


>> On the 2401, the window was
>> electrically-operated, and the interlock was probably a bit more
>> reliable. <SNIP>
>> The electric windows were much more popular with operators.


The ones where the access window rose *up* through a slot in
the top of the unit.  Was a Real PITA for operators pre-staging
multi-reel jobs.  They'd stack reals number 2->n on top of the
unit in preparation for the subsequent mount requests.  If they
were lucky, the reels only slid back on the top of the drive --
behind the up-raised glass.  Usually tho', the reels were
dumped on the floor.
'Twas a big problem for the old time, long time IBM shop operators.

Jonesy
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Mon, 01 Aug 2005 10:40:56 GMT  
 Card Columns (was Why did they make ... ?)

Quote:



>> On the 2401, the window was
>> electrically-operated, and the interlock was probably a bit more
>> reliable. <SNIP>
>> The
>> electric windows were much more popular with operators.

>As I recall, this was not nearly as "popular with operators" as sitting
>the mini-skirted junior op on top of the line printer and pressing the
>button to raise the lid.
>Sadly I dont recall the model numbers of the printer or the girl .

1403N1 and 36-26-36 respectively?

Quote:
>Sorry to break your train of thought... couldn't resist ;-)

That's what this froup is for, isn't it?

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Mon, 01 Aug 2005 09:39:36 GMT  
 Card Columns (was Why did they make ... ?)


Quote:
>As far as interlocks are concerned, you may recall that the 729 had a
>window that had to be raised manually.

I recall swinging a door open, but I might be thinking of the 727.

--
     Shmuel (Seymour J.) Metz, SysProg and JOAT

Any unsolicited commercial junk E-mail will be subject to legal
action.  I reserve the right to publicly post or ridicule any
abusive E-mail.

I mangled my E-mail address to foil automated spammers; reply to
domain Patriot dot net user shmuel+news to contact me.  Do not



Mon, 01 Aug 2005 15:44:42 GMT  
 Card Columns (was Why did they make ... ?)


We got STC 3420-equivalent drives to replace Potter kit; trust me, it
was a big step up in reliability. The odd thing is that in the 1960s
Potter had a good reputation.

--
     Shmuel (Seymour J.) Metz, SysProg and JOAT

Any unsolicited commercial junk E-mail will be subject to legal
action.  I reserve the right to publicly post or ridicule any
abusive E-mail.

I mangled my E-mail address to foil automated spammers; reply to
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Mon, 01 Aug 2005 15:47:25 GMT  
 Card Columns (was Why did they make ... ?)


Quote:


> The ones where the access window rose *up* through a slot in
> the top of the unit.

The 24xx wernt much better. Novice operators tended to put tapes on top of
the cabinet, and lo and behold, as soon as the motor started, one could see
2-3 m long pieces of tape flapping around, sometimes up to the ceiling. And
then they tried of course to put the tape back on the spool, with their
greasy fingers.

Nico



Mon, 01 Aug 2005 17:30:30 GMT  
 Card Columns (was Why did they make ... ?)

Quote:



>>> On the 2401, the window was
>>> electrically-operated, and the interlock was probably a bit more
>>> reliable. <SNIP>
>>> The electric windows were much more popular with operators.

>The ones where the access window rose *up* through a slot in
>the top of the unit.  Was a Real PITA for operators pre-staging
>multi-reel jobs.  They'd stack reals number 2->n on top of the
>unit in preparation for the subsequent mount requests.  If they
>were lucky, the reels only slid back on the top of the drive --
>behind the up-raised glass.  Usually tho', the reels were
>dumped on the floor.
>'Twas a big problem for the old time, long time IBM shop operators.

...and for DECSystem-10 shops that bought the rebadged Storage Tech
9-track drives.  You got the drives, an S/360-compatible controller,
and a bus converter (DX-10?) that attached the IBM interface on the
Storage Tech controller to the guts of the Kx-10.  DEC sold them
as the ... TU-70?  TU-78?  We had both and I can't recall which
was which.

Cancel that last; they were TU-70 (with the controller rebadged as
a TX-01).  I just found a copy of the (1982) user's guide for the shop
which had an equipment list.  It also had a price list: $130/hour
for KL-10 CPU time, $2.25/kword-hour, and $0.0004/line printed.

I never understood why the controllers were configured with the 2-channel
switch.  I considered attaching the unused second interface to our IBM
system, but the DEC CEs stated that if we did, they would refuse to
service the box.

You also got the problem of very frequent broken glass.

Joe Morris



Mon, 01 Aug 2005 22:10:47 GMT  
 Card Columns (was Why did they make ... ?)

Quote:

>>As far as interlocks are concerned, you may recall that the 729 had a
>>window that had to be raised manually.
>I recall swinging a door open, but I might be thinking of the 727.

You could do that too, and if you did you could pull out the interlock
bar (upper right corner of the doorframe?) and run the drive with
the guts exposed.

Just like the recent posting about an experienced console users on a
S/360 running his fingers along the bitswitches, an experienced 729
operator knew just how much force to exert on a door to start close
it firmly but without damage...just like they knew how many turns to
spin the takeup reel to get past the BOT reflector (or where the
reflector should have been...<grin>) and how hard to spin the unit
number dial to set the proper connection.

Joe Morris



Mon, 01 Aug 2005 22:16:21 GMT  
 
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