IBM 1401 Restoration Project
Computer History Museum

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This web site is an IBM 1401 Restoration Chronology, and information resource.
Daily Reports, Restoration Team Bios, 1950s Teams Bios, Table of Contents, Current Status Report (March 2008 ), MajorEvents
Reunion & 50th Anniversary of the IBM 1401

Robert Garner, Proprietor ;-)) w - 408-927-1739
Technical & Administrative e-mail. -
Ed Thelen, Recorder H 510-742-1146, C 510-828-7673 - Comments about web site e-mail ;>)
1401 Room Phone # 650-810-1037
Image permissions; Donations

General Pictures
The two IBM 1401 systems being restored (can demo) in the Computer History Museum. (June 2009)
Larger images
150 k bytes
700 k bytes
Larger images
150 k bytes
500 k bytes

1401 Operators Panel
Gene Amdahl, April 2005
I'm not so sure!!
Doug Englebart w Bob E.
(Women brave our culture ;-)

Nathan Myhrvold
Joe Preston and
Frank King

Matthais Goerner
We have fun ;-)
Nov 2008, L->R Bob E,
Ron W, Bill F, Glenn L,
Ed T, Robert G, Allen P,
Frank K, Joe P, Judith H, Stan P
1401 Project images from Marcin Wichary - 1, 2, 3, 4, 5, 6

Table of Contents - Major Topics (some major topics are on other pages)
Project
People and stories
What is an IBM 1401?
1401 Hardware System
1401 Processor 		1402 card reader
1402 card punch
1403 printer
729 tapes
729/TAU Emulator 		Unit Record Equipment
SMS Cards
Components/Devices
General Hardware
1401 Software 		Geek fun, Software
Geek fun, Hardware
1401 Inventory/location
Related Restorations
Other 		Demo & Education
1401 Stories
1401 Movies and Music ;-)
Nov 10, 2009 Reunion & 50th Anniv.

Table of Contents - Detail
Please note: Users of dial-up lines report troubles accessing Adobe .pdf files larger than about 1 megabytes. The symptom they see indicates file corruption. The "corruption" seems to be time-outs or transmission problems. Adobe employees claim using Reader version 7 is better - or download the whole file first to your system then access it with Adobe Reader. :-((

Project

CHM mission statement:

"Our Mission
"The mission of the Computer History Museum is to preserve and present for posterity the artifacts and stories of the information age. As such, the Museum plays a unique role in the history of the computing revolution and its worldwide impact on the human experience."
Our efforts aid the presentation efforts of the above statement.

List of Daily Reports:
2004, Jan, ... Jun, Jul, Aug, Sep, Oct, Nov, Dec
2005, Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec
2006, Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sept, Oct, Nov, Dec
2007, Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sept, Oct, Nov, Dec,
2008, Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sept, Oct, Nov, Dec
2009, Jan, Feb, Mar, Apr, May, June, July,

Light at the end of the tunnel.
As the astronomers call it First Light. - Oct 19, 2005

- the 1403 printer works in all 132 columns - Jan 18, 2006
- all basic and installed optional instructions (including Multiply and Divide) work - April 26th, 2006
- the Overlap feature is no longer stuck "ON" interfering with programmed card reading - May 27th, 2006
- the 1402 card reader and card punch are correctly aligned and working well - mid August, 2006

Scheduled Work Days

The main group meets at 10 AM Wednesdays at the 1401 restoration room at the computer History Museum, Mountain View, Ca.

The sub-group involved with the magnetic tape interface (Tape Adapter Unit - TAU) has been coming in Thursdays to reduce congestion on the 1401 processor. They usually start about 10:30 and work to 7.

Normally the museum is locked and a pass "key" is required for entry - "regulars" each have one or come with friends. (There is no one in the lobby to let you in.) If you wish to help us and don't have a pass "key", call the 1401 room 650-810-1037 between 10 and noon. (This number is not on the CHM phone list.) We take a noon break at a room with no phone.


How to visit informally.

Come Wednesday at 1 P.M. for a tour of the Computer History Museum, Map of 1401 N Shoreline Blvd Mountain View, CA 94043 or this map. (The guest entrance is on the *North* side of the building.) Ask your docent to include a view of the 1401 room in the tour. Come early as some of us start leaving at 3:00 to avoid the commute traffic.

House Rules

  1. We are dealing with artifacts of considerable rarity and historical interest, to be kept in historically accurate status as possible/practical.

  2. from "CHM Restoration Guidelines"
    "At least TWO team members must be present whenever the work on major components or the system has potential dangerous energy (either electrical or mechanical) exposure. Team members can include a member of the curatorial staff. Work is ideally conducted as a team and with a partner to share knowledge, responsibilities and to provide project continuity. Good engineering judgment and practices are to be used when working on any aspect of the machine or system or operating the machine and its peripherals.

    from Grant Saviers, Chm, Restoration Committee
    " The intent is to explicitly permit solo work on a PC, or programming, demonstration, or other cosmetic activities on systems by individuals, as long as no "dangerous energy (either electrical or mechanical) exposure" is present."
    and
    "I would add [...] that those working on restorations do have a responsibility pro-actively notify docents and visitors of any hazardous situations. Volunteers can not be so singularly focussed on restorations that they fall short of helping to create a safe and great visitor experience.
    Also, I believe personnel safety and welfare matters should be directed to Gary Matsushita or John Hollar and if there are debates about these, they should be the arbiters."

  3. Log "everything". You might forget how some wire or structure was connected, diagram and/or photograph it.

  4. Our "official Museum contact" is Karen Kroslowitz.

  5. Emergency phone numbers, in priority order

People and Stories

Action Groups

- IBM 1401 C.E.s were trained on, and expected to fix, all the below.

1401 Processor w/ 1406 added memory, 1402 Card Reader/Punch, 1403 Printer
729 Tape Units, Software

Our "working" environment, - er - Play Room, decorations by Ron Williams, Master Welder, Court Jester, Jack of All Trades, ... ;-))


Entrance
Ed's Citation
Amnesty ;-))
Nov. 2005
Mascot w Bug ;-))

Mascot 		The Baby Mascot on the left was given by Ron Williams to Betsy Toole on her retirement as CHM Volunteer Coordinator. Betsy, you were so helpful, cheerful and warm - Thank You.
New Baby Mascot
Teasing Allen

More Teasing Allen
Better View 		In the 1960s Camille Bounds of Gilroy made Christmas wreaths from IBM cards to help pay for her husband's tuition at Caltech. Photo credit: David A. Laws
A CHM staff member said that since we are men, working with machinery, the air must turn blue occasionally. Oddly, there is no "blue air" in our 1401 room. The IBM folks said that profanity or vulgarity (especially near a customer) was grounds for instant dismissal.

What is an IBM 1401?

A 1401 - History and Fundamentals by Robert Garner

I (Ed Thelen) am qualified to tell you because I used to maintain G.E. Computer equipment trying to compete with the 1401 - and I know all too well!
Basic IBM 1401
with added memory 16,000 characters max.

this system had tapes

a guide to the drawings

1401 Core
Simon Barratt image
The 1401 computer, introduced in 1959, used discrete transistors to provide decimal (0-9) addressing and arithmetic. It provided an effective way for card data processing shops to convert to "computers". The 1402 card reader/punch was excellent, the 1403 printer was superb. Interfaces to magnetic tape drives, discs, and other peripherals were available.
The 1401 software was very "primitive". No operating system, no graphical user's interface, no windows, - in other words, only your code was running, and you had a chance of knowing what was going on. :-))
Obviously things had to get better, and we can now blame Bill Gates for everything - everyone agrees this is an improvement??
The 1401 system was really "user friendly" - say the machine stopped because there were no cards in the card reader. You looked at the Operator's Panel, and there was the Card Read instruction. You the operator put a tray of cards into the card reader, depressed a button, the machine started to run again - and life was good - and simple :-)
Why did we have to "improve" things?
The 1401 has an unusual architecture, which uses "word marks" to show the end of numbers or fields. It is easy to play with *big* exact numbers. Say you have two 30 digit numbers on an 80 column IBM card. You want to multiply them and print the result. You issue a card read instruction, and the two numbers are read into memory, in decimal format. You set two word marks to define the high ends of the 30 digit input numbers, and set a word mark in the print area to define the high end of the resultant 60 digit multiply. Do a multiply sending the result to the print area, and issue a print command and the 60 decimal digit answer is on the paper in the printer. - Just try that with your 32 bit binary word Pentium C++ Windows GUI machine.
Folks interested in the definition and development of the 1401 computer and the 1403 printer are recommended to "IBM's Early Computers" by Bashe, Johnson, Palmer & Pugh, 1986, MIT Press, pages 459-495. (Available 2nd hand) - to whet your appetite - The French proposed the transistor technology, ferrite-core memory and variable-word-length characteristic in a June 1955 conference in Sindelfingen Germany. The Americans worried about offshore development in small laboratories and did the design in Endicott. The 702-705 field terminating character was replaced in the 1401 by a special (8th) bit. It was also determined that a plug board added a great deal of cost and was eliminated. :-))

System Characteristics of our 1401 system, summary

1401 computer
1,400 to 4,000 character memory, clock speed 87.5 kilohertz, time to get one character from memory is 11.4 microseconds, time to fetch a seven character instruction is 80 microseconds.

Using a seven character add instruction (including six characters of source & destination addressing) to add two positive 6 character numbers took the above 80 microseconds, plus 2 times 11.4 microseconds to check the signs of the operands, plus 3 times 11.4 microseconds per character giving 309 microseconds. (If an addition results in a negative, more time is required to adjust the result.)

DTL (Diode Transistor Logic) using Alloy junction transistors is mounted on SMS cards. Two styles of logic are used, "T" and "U", each having different "1" and "0" voltages. About 3,000 SMS cards are used.

1402 Card Reader, Card Punch
Card reader speed is 800 cards/minute (if you issue the next read fast enough) else lower per minute.

Card punch speed is 250 cards/minute

1403 Printer
600 132 character lines per minute - normal alphabetic printing. Our 1403 controller has a buffer permitting concurrent computing and printing.

Noise, with the cover closed, at about 2 feet in front is about 85 dbA. With cover open, about 94 dbA. (for details)

1406 Extended Memory
An added 4,000 to 12,000 characters of memory, in 4,000 character increments. Permitting a maximum memory in a 1401 system of 16,000 characters. This addition also added the Modify Address command.
729 Magnetic Tape Drives

Other input/output devices

"IBM 1405 Disk Storage", based on the 350 Disk Storage (RAMAC) announced 1960
1407 Inquiry Terminal, with typewriter
from Bill Worthington August 1, 2008 Updated August 3, 2008
There was also a plethora of other input/output devices which attached to the 1401. ... from 1401 manuals that I have in my stash.
  • 1009 Data Transmission Unit
  • 1011 Paper Tape Reader
  • 1012 Paper Tape Punch
  • 1301 Disk Storage (See comment below too.)
  • 1404 Printer
  • 1407 Console Inquiry Station (It was not an operator's console.)
  • 1418 Optical Character Reader
  • 1428 Alphameric Optical Reader
  • 1412 Magnetic Character Reader
  • 1419 Magnetic Character Reader
  • 1026 Transmission Control Unit
  • 1231 Optical Mark Page Reader
  • 1285 Optical Reader
  • 7740 Communication Control System
  • 7770 Audio Response Unit

Of the machines above, I programmed the 1401 to support the 1412 and 1419 while working for a bank. While working as a Systems Engineer for IBM, I supported customers who had 1404, 1418, and 1231 machines installed. I installed the first fiber-optic version of the 1231. It was hand-carried from Rochester, MN to a college in RI.

The 1301 Disk Storage looked a lot like the 1405, but had at least two actuator arms.
... the 1311 Disk Storage was much more widely used than the 1301 or 1405 Disk Storages.


The 7330 Magnetic Tape Unit was a low cost alternative to the models of the 729.

Some IBM 1401 web links:

1964 Ballistic Research Labs report, IBM, Columbia University, Tom Van Vleck, Van Snyder's 1401 links, mine
LaFarr Stuart has a web page What makes the 1401 so interesting?,
Movie of Jan 18, 2006 - progress, see #3, IBM 1405 disk storage
1401 Data Processing System from IBM web site

1402 Card Reader Character Set
"IBM CARD CHARACTER CODE"
from http://www.bitsavers.org/pdf/ibm/140x/R29-0044-2_1401SPStraining.pdf
ZONE
PUNCH 		NO 0 1 2 3 4 5 6 7 8 9 3-8 4-8
12 "X"& +0 A B C D E F G H I . "lozenge"
11 "Y"- -0 J K L M N O P Q R $ *
0 xxx xxx / S T U V W X Y Z , %
NO blank 0 1 2 3 4 5 6 7 8 9 # @
Notes:
xxx is an illegal punch combination
# is an = in the Fortran character set
Mike Albaugh comments
" [your web page] calls the 12-4-8 punch a "square". We always called it a "lozenge" Also, the "commercial" and "Scientific" character sets for the 026 were different, although at this point I only remember that the commercial '&' (12-only) was a scientific '+', and that the '#' was "something else" :-) I could have sworn that 12-6-8 was a '+' in 029 code, but you show it as "Less than", albeit unprintable."

John Van Gardner points out

The earliest machine that I know of that used the 7 bit BCD code was the 702 which evolved from TPM (Tape Processing Machine). The seven track 726 Tape drives used on the 702, 704 and 705 had the tape tracks labeled as 1248ABC. Your 729s have inherited this.

Attached is a pdf file of pages 31-33 of the 702 Preliminary Manual found at: http://www.bitsavers.org/pdf/ibm/702/22-6173-1_702prelim_Feb56.pdf I have highlighted in yellow the pertinent part about the code.

There is some good information about the TPM and 702 around page 213 of the book "IBM's Early Computers" by Emerson W. Pugh.

A list of all 64 6 bit codes for the IBM 1401 in binary and colating order from Stan Paddock.

From Bill Worthington, a reference card, ,

And a 1401 card code from Bob Feretich

A 1401 Card Code from Robert Garner

HTMLized and Sorted by BCD or OCTAL value

TABLE OF UNPRINTABLE CHARACTERS

(from Part No. 451424 - Diagnostic Function Test)
-LEFT PARENTHESIS 12 5 8     MZ-MINUS ZERO 11 0  
-WORD SEPARATOR 0 5 8     AP-APOSTROPHE 0 6 8
-TAPE SEGMENT MARK 0 7 8     DE-DELTA 11 7 8
-GROUP MARK 12 7 8     PZ-PLUS ZERO 12 0  
-RIGHT PARENTHESIS 11 5 8     TM-TAPE MARK   7 8
SE-SEMICOLON 11 6 8     CO-COLON   5 8
LT-LESS THAN 12 6 8                    
Standard Fortran printer carriage control, 1st character:
blank, single space;
1, top of form;
0, double space;
+, overprint (not supported everywhere).
Feel free to consult your friendly Unix man page for the program 'asa' for further reference.

Major Equipment Inventory - incomplete

Product # Name Model Serial # Informal ID
1401 computer . 1401-40-28421-E4 .
1406 extended memory . 1406-40-20066-61 .
1402 reader/punch . 1402-1-1600743-C2 .
1403 printer . 1403-40-11401-A3 .
729 tape drive V 0729-3534825B4 Green dot
729 tape drive V 3534949C4 Red dot
729 tape drive IV 35-21062-L1 .
729 tape drive II 21062 .
729 tape drive II 2012 .
077 Collator . 077-40-22036 .
083 Sorter . 33619
(on casting) 		?Rusty? ;-))

Documation Card Reader instructions and software 
From: Bill Selmeier [mailto:bills@right-net.com] 
Sent: Tuesday, October 10, 2006 4:57 PM
To: Ronald Mak

for when you need it, here is the software [CardRead.zip] 
for the Documation Card Reader.  

Load this to a directory on a  PC, connect the usb cord from 
the card reader,  fire up cardread.exe. (there are insturctions in 
the included word file and the pdf) and use deckview.exe to look at 
the file created on your disk.  Bill Worthington probably remembers 
how this program runs if you have a problem or describe it and I'll 
try and help.  But the best support is from Brian Knittle who wrote 
these programs and made the usb convertor box.  He is a museum 
volunteer that lives up in  Emeryville.

Good Luck...

Bill

Source of IBM cards 
Supplier:
   Cardamation Company Inc.
   c/o Bob Swartz
   1041 West Bridge Street
   Phoenixville, PA 10460.

Tel:  610-935-9700,  800-848-01718
cell:  267-221-2954,  Fax  610-935-7340

Card Stock Specs:
   Style:  5081
   Color:  Natural
   Corners:  Square
   Corner cut:  Upper Left only
   Cost:  $14 per 1,000


  also here

Image permissions:
Many of the images on this web site:
a) were photographed by me (Ed Thelen), with frequent contributions by Robert Garner and others,
b) are of property (computers) owned by Computer History Museum.
I am advised by the Museum (July 20, 2006) that
Judy Strebel is the media archivist at the Museum and in general, handles requests for image usage. strebel@computerhistory.org.

Donations
To donate 1401 specific manuals, equipment or supplies to the project,
e-mail Robert Garner or Ed Thelen

To donate general items to the museum - from Karen Kroslowitz, Registrar

Our curatorial team meets weekly to discuss offers of new donations, following a thorough search of our database to determine whether the Museum's collection may already include representative examples of the material(s) you are offering. Either I or the Associate Registrar will contact you if we require additional information or photographs of your item or when a decision has been reached, typically 1-2 weeks.

Because specific information is required for the curatorial team to make decisions on donation offers, we encourage prospective donors to review the information and use the easy online donation submission form available at http://www.computerhistory.org/collections/donateArtifact/.

Thank you for your interest in the Museum. Our world-class collection would not exist without the generosity of prospective donors like you.

With thanks and best wishes,

-Karen

This page started June 5, 2004
D, WP, GCR, GG, NY, stern,