[1401_team] 1401 Guide / Poster Draft #2

Thu Mar 16 09:10:43 PST 2006

>From what I have read of the 360/30 its microcode was in two "gates" of 
CROS. The first "gate" contained the 360 integer instruction set 
microcode. The second :"gate" could be ordered in several configurations:
Empty
360 floating point microcode
Emulation microcode

If the second "gate" contained emulation microcode, then some switches 
needed to be set to select either 360 mode or emulation mode and the 
machine rebooted (IPL).

Am I correct?
-- 
          R. Tim Coslet 
          rtcoslet at rockwellcollins.com 
          (408)-532-4505 
          Rockwell Collins Display Systems 

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Re: [1401_team] 1401 Guide / Poster Draft #2

A list for participants in the IBM 1401 Restoration at the Computer 
History Museum.  Permission is hereby granted to the Museum to use the 
content for any purpose.
===================================================================

Robert, the S/360 Model 40 (2040) also had 1401 emulation.  Both it and 
the 2030 were announced as having this feature.  (The S/360 Model 50 
(2050) emulated the 1410/7010 and the 7070.  The S/370 Models 125, 135 
138, 145 and 148 also provided 1400 compatibility features.)

Initially, 1400 (1401/1440/1460) emulation was a standalone operation. The 
operator activated (loaded?) the 1400 microcode and then the card reader 
(or tape drive) became the load device for the 1400 program.  There was a 
need to run 1400 programs concurrently with S/360 programs and two DOS/360 
Type III programs were offered called Compatibility Operating System (COS) 
and COMPAT whose (acronym expansion I can't remember.)  COMPAT eventually 
was the one selected for formal support.

The last vestige of 1400 support was a program offering for both the 
DOS/VSE and OS/MVS platforms which checked to see whether the S/370 
processor had a 1400 emulation feature, or not.  These features did not 
provide full 1400 simulation.  If the emulation feature was there, it 
provided a hardware assisted (not full emulation) support.  If it was 
absent, then the program simulated the 1400 processor.  The program 
numbers began either 370N-EU-??? or 370S-EU-???.

Of minor interest may be the fact that the S/360 sales reps were not paid 
a commission when emulation features were included on a system.  It was 
deemed to be a short term usage feature which would be returned to IBM 
once the conversion to S/360 languages and operating systems were 
completed.  As I remember, commission was finally given about two years 
after the S/360s were delivered as IBM realized that the feature was more 
permanent that initially expected.
Regards, Bill
BillWorthington at comcast.net

1401_team at computerhistory.org wrote: 
A list for participants in the IBM 1401 Restoration at the Computer 
History Museum.  Permission is hereby granted to the Museum to use the 
content for any purpose.
===================================================================

Robert,
I've repeated your questions here along with my answers to make it easier 
to read: 
Q: Which IBM 360 model was first to provide 1401 emulation? The model 25 
or 30?
A: The 2030 was the first to provide 1401 emulation. The 2025 was not 
announced until 1968.

Q: Re: tabulating machines,  Is this the generic set from the 1950's 
replaced by the 1401:
407 printer, 514 reproducer, 080 sorter, 077 collator?
A: In my experience most were bigger customers upgrading from Tab 
Equipment to 1401 and were using
multiple 407 Tabulators, 519 Reproducers, 083 Sorters, 088 Collators.

Q: I couldn't help but to notice the decision to drop the RAMAC 350 line 
in favor of the 
1401 with the disk as a peripheral (1405, 1311).
This appears to me to signify the end of San Jose's nascent 
"general-purpose" computing phase.
What were the main reasons the 1401 won out?
A: The 305 was vintage 1956 and used vacuum tubes, relays and Control 
Panels. 
     The 1401 was 1960 new, smaller, solid state, cooler, fast and no 
control panels
     CPU Speed - The 305 was tied to it's internal drum memory speed 
               305 Drum w10ms/rev and 12usec/bit=96usec/character vs 1401 
11.5 usec character (minimum of 9 times faster)
     Disk storage twice the capacity and almost triple the speed
              350=5m at 8.8kb/sec   1405=10m at 22.5kb/sec
     305=Max Record length of 100 characters
    1403 Printer speed
    1401=NO CONTROL PANEL WIRING (by 1959 everyone hated control panels)
     Tape Drives

John Falk

1401_team at computerhistory.org wrote: 
A list for participants in the IBM 1401 Restoration at the Computer 
History Museum.  Permission is hereby granted to the Museum to use the 
content for any purpose.
===================================================================

Thanks everyone for your informative and apropos feedback to my V2 draft 
1401 poster/factoid chart! 
I appreciate all the help in sorting out the myriad of information.
I'll incorporate your feedback and send out an updated version this 
weekend.

A request:  Please include your full name on your emails to the 
"1401_team".
Now that the alias is under control of the Museum's MailMan program,
it looks like it's stripping away your mail header "From" path.

Some responses:

Everyone may not be aware, but David Macklin was actually a codeveloper of 
the 1401 FORTRAN compiler!
See his bio on our web site.  We also have the IBM J R&D article about the 
compiler posted there.

The next phase of my poster effort is to add some pictures of the key 
components,
which should make the info more user friendly.
I'll also keep a smaller, picture-less (pdf) factoid version for easy 
emailing to folks
like magazine writers, or students who need more information for say a 
school report.
I don't want the info to be too technical (we have manuals for that), but 
not too watered down either.
In the spirit of being a "History Museum", the facts should be as accurate 
as possible.
I'd like to place the poster next to the 1401 room exterior entrance door;
certainly it can go inside the anteroom as well.
Note that the 1401 room is usually the last stop on Visible Storage tours.

Re: the Honeywell "clone":  Honeywell defined its H-200 ISP to be a 
superset of the IBM 1401 ISP"
is from Gordon Bell's book. 
http://research.microsoft.com/~gbell/Computer_Structures__Readings_and_Examples/00000245.htm
IBM Early Computers I think mentions Honeywell as breathing down the 
1460's team back;
i.e., it had better performance while the infant 360 was still on drawing 
boards.

Speaking of unusual 1401 peripherals, I've run into Mike Melas at IBM 
Almaden Research.
He worked on the 7770 Voice Response System that could synthesize 
Japanese,
German, English, and French.  Used by banks to call customers.
http://www.mindspring.com/~ssshp/ssshp_cd/ss_ibm.htm#TASS2
He will be visiting us this next Weds.

Is Sort 7 equivalent to  "tape sort" and "disk sort" ?
I should list IOCS as well.  (I have a listing of it, btw.)

Which IBM 360 model was first to provide 1401 emulation?
The model 25 or 30?
I assume it immediately end-of-lifed sales of 1401s.

I couldn't help but to notice the decision to drop the RAMAC 350 line in 
favor of the
1401 with the disk as a peripheral (1405, 1311).
This appears to me to signify the end of San Jose's nascent 
"general-purpose" computing phase.
What were the main reasons the 1401 won out?
Because it had no plug boards and a larger main memory?
(I'll have to see if I can get hold of the the internal design memos 
referenced
in Early IBM Computers book.)

Re: tabulating machines,  Is this the generic set from the 1950's replaced 
by the 1401:
407 printer, 514 reproducer, 080 sorter, 077 collator?
And the 1401 directly replaced the 650 computer.

Thanks,

- Robert

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