IBM 1401 (Card system)

The IBM 1401, the first member of the IBM 1400 series, was a variable wordlength decimal computer that was announced by IBM on October 5, 1959. It was withdrawn on February 8, 1971. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... The IBM 1400 series was a family of mid-range buisiness computers that IBM sold in the early 1960s as a replacement for unit record equipment. ... For other uses, see Decimal (disambiguation). ... This article is about the machine. ... International Business Machines Corporation (IBM, or colloquially, Big Blue) (NYSE: IBM) (incorporated June 15, 1911, in operation since 1888) is headquartered in Armonk, New York, USA. The company manufactures and sells computer hardware, software, and services. ... is the 278th day of the year (279th in leap years) in the Gregorian calendar. ... Year 1959 (MCMLIX) was a common year starting on Thursday (link will display full calendar) of the Gregorian calendar. ... is the 39th day of the year in the Gregorian calendar. ... Year 1971 (MCMLXXI) was a common year starting on Friday (link will display full calendar) of the 1971 Gregorian calendar. ...

From the IBM Archives:

The following is the text of an IBM Data Processing Division press fact sheet distributed on October 5, 1959.

The all-transistorized IBM 1401 Data Processing System places the features found in electronic data processing systems at the disposal of smaller businesses, previously limited to the use of conventional punched card equipment. These features include: high speed card punching and reading, magnetic tape input and output, high speed printing, stored program, and arithmetic and logical ability.

The 1401 may be operated as an independent system, in conjunction with IBM punched card equipment, or as auxiliary equipment to IBM 700 or 7000 series systems.

The IBM 1401 was also commonly used as an off-line peripheral controller in many installations of both large "Scientific Computer"s and large "Business Computer"s. In these installations the big computer (e.g., an IBM 7090) did all of its input-output on magnetic tapes and the 1401 was used to format input data from other peripherals (e.g., the punch card reader in the IBM 1402 card reader/punch) on the tapes and transfer output data from the tapes to other peripherals (e.g., the punch card punch in the IBM 1402 card reader/punch or the IBM 1403 lineprinter). IBM 7090 console The IBM 7090 was a second-generation transistorized version of the earlier IBM 709 vacuum tube mainframe computers and was designed for large-scale scientific and technological applications. The 7090 was the third member of the IBM 700/7000 series scientific computers. ... Compact audio cassette Magnetic tape is a non-volatile storage medium consisting of a magnetic coating on a thin plastic strip. ... Punched cards (or Hollerith cards, or IBM cards), are pieces of stiff paper that contain digital information represented by the presence or absence of holes in predefined positions. ... The IBM 1403 Printer was introduced as part of the IBM 1401 computer in 1959, but had an especially long life in the IBM product line. ... Fragment of lineprinter cylinder with the type of % The Line printer is a form of high speed impact printer in which a line of type is printed at a time. ...

During its lifetime about 20,000 total systems were manufactured (photo), making the IBM 1401 one of IBM's most successful products. From the IBM Archives:

The monthly rental for a 1401 was $2,500 and up, depending on the configuration. By the end of 1961, the number of 1401s installed in the United States alone had reached 2,000 -- representing about one out every four electronic stored-program computers installed by all manufacturers at that time. The number of installed 1401s peaked at more than 10,000 in the mid-1960s, and the system was withdrawn from marketing in February 1971.

Elements within IBM, notably John Haanstra, an executive in charge of 1401 deployment, supported its continuation in larger models for evolving needs (e.g. the IBM 1410) but the 1964 decision at the top to focus resources on the System/360 ended these efforts rather suddenly. To preserve customer investment in 1401 software, IBM pioneered the use of microcode emulation, in the form of ROM, so that some System/360 models could run 1401 programs. Such emulation continued well into the modern era... in some cases, perhaps, until Y2K efforts caused the still-running 1401 code to be rewritten. The IBM 1410 was a variable wordlength decimal computer that was announced by IBM on September 12, 1960 and marketed as a midrange Business Computer. It was withdrawn on March 30, 1970. ... Also Nintendo emulator: 1964 (emulator). ... System/360 Model 65 operators console, with register value lamps and toggle switches (middle of picture) and emergency pull switch (upper right). ... A microprogram is a program consisting of microcode that controls the different parts of a computers central processing unit (CPU). ... This article is about emulation in computer science. ... Read-only memory (usually known by its acronym, ROM) is a class of storage media used in computers and other electronic devices. ... The year 2000 problem (also known as the Y2K problem and the millennium bug) was a flaw in computer program design that caused some date-related processing to operate incorrectly for dates and times on and after January 1, 2000. ...

During the 1970s, many installations in India and Pakistan used the 1401 and some of today's Indian and Pakistani software entrepreneurs started on this machine.An IBM 1401, the first computer in Pakistan, was installed in Pakistan International Airlines. Pakistan International Airlines Corporation, more commonly known as Pakistan International Airlines or PIA (Urdu: پی آئی اے يا پاکستان انٹرنیشنل ایرلاینز), is the national flag carrier airline of Pakistan, based in Karachi. ...

A 1401 Restoration Project is in process at the Computer History Museum in Mountain View, California, complete with the old "false floor" of the mainframe era, used to hide cabling^[1]. The Computer History Museum in Mountain View. ... Mountain View is a city in Santa Clara County, in the U.S. state of California. ...

Architecture

The 1401 used IBM's binary-coded-decimal (BCD) character coding. Each byte (or alphameric character) in the 1401 was represented by six bits, called A, B, 8, 4, 2 and 1. The A and B bits were called zone bits and the 8, 4, 2 and 1 bits were called numeric bits. Associated with each six-bit byte were two other bits, called C for odd parity check and M for word mark,^[2] in the following format: In computing and electronic systems, Binary-coded decimal (BCD) is an encoding for decimal numbers in which each digit is represented by its own binary sequence. ... In computer science a byte (pronounced bite) is a unit of measurement of information storage, most often consisting of eight bits. ... This article is about the unit of information. ... Look up Parity in Wiktionary, the free dictionary Parity is a concept of equality of status or functional equivalence. ...

 C B A 8 4 2 1 M 

The 1401 was available in five memory configurations: 1.4K^[3], 2K, 4K, 8K, or 16K (a very small number of 1401s were expanded to 32K by special RPQ - Request for Price Quotation). An optional "Advanced Programming Option" allowed for additional flags for 3 bytes within the first 100.

An IBM 1401 core memory address consisted of three six-bit bytes. The decimal address within 000 to 999 was specified by the 8-4-2-1 bits of these bytes. The zone bits of the high-order byte specified an increment, A 1000, B 2000, A and B 3000, giving an addressability of 4,000 bytes in all. The zone bits of the low-order byte specified increments of 4000, 8000, or 12000, to address 16,000 bytes (with an IBM 1406 memory expansion unit). The zone bits of the middle byte were used to specify index registers, one of many optional features. A 16×16 cm area core memory plane of 128×128 bits, i. ... An index register in a computer CPU is a processor register used for modifying operand addresses during the run of a program, typically for doing vector/array operations. ...

Instructions were of six lengths (1, 2, 4, 5, 7, 8). One-byte instructions consisted of only an opcode. These were either defined as one-byte instructions or were chained instructions, using the addresses left by the previous instruction when it completed. Two-byte instructions consisted of an opcode and a modifier byte. Four-byte instructions consisted of an opcode followed by an address, five byte instructions an opcode, address and modifier byte, seven byte instructions an opcode followed by two addresses, and eight byte instructions an opcode, two addresses and a modifier byte. Microprocessors perform operations using binary bits (on/off/1or0). ...

Instructions were only valid if the wordmark was set on the low-order (opcode) byte and nowhere else in the instruction. Instruction fetching stopped and execution began when another byte with the wordmark set was encountered (the valid opcode byte of the next instruction); there were two exceptions to this rule:

1. The dyadic SET WORDMARK instruction, which set two wordmarks, is seven bytes even without a following valid opcode.
2. The unconditional BRANCH INDICATOR instruction, is five bytes even without a following valid opcode.

Note: Other than these two exceptions, if no valid opcode was found by the 9th byte, the instruction was treated as an 8 byte instruction, but the computer continued scanning for a valid opcode (ignoring the bytes) until one was found before beginning execution or an error was detected (e.g., the end of memory). This was usually considered sloppy programming but not necessarily an error.

When the LOAD button on the IBM 1402 reader/punch was pressed, a card was read into the card read buffer (core locations 1-80), a wordmark was set in location 1 (validating the first instruction on the card), and clearing the wordmarks in locations 2-80. Thus, the first instruction of any bootstrap program was a dyadic set wordmark, which validated two other instructions. In practice, the first few cards of a card-deck bootstrap program would consist entirely of dyadic set wordmark instructions, no-op instructions, and a "read card and branch" instruction, which would set up a pattern of wordmarks in the card read buffer. The "read card" instruction did not change any wordmarks in the card read buffer. By use of no-op instructions of various lengths, the next few cards would conform to this pattern of wordmarks. In computing, a buffer is a region of memory used to temporarily hold output or input data, comparable to buffers in telecommunication. ... In computing, Bootstrapping refers to a process where a simple system activates another more complicated system that serves the same purpose. ... NOP or NOOP (short for No OPeration) is an assembly language instruction, sequence of programming language statements, or computer protocol command that does nothing at all (besides wasting clock cycles). ...

Software

Software on the 1401 included:

• Autocoder a more advanced assembler, required at least 4K memory locations.
• FARGO (Fourteen-o-one Automatic Report Generation Operation), a predecessor of RPG, required 4K.
• FORTRAN II was available for systems containing at least 8K memory locations; the 1401 Fortran compiler is described in Haines, L.H. (1965), below. The Fortran compiler, to generate code for small memories, used a pioneering form of interpreted "p-code" although, of course, its programmers had no name for what it is that they did.
• FORTRAN IV was available for systems containing at least 8K memory locations and either 4 tape drives or 1 IBM 1311 disk drive.
• RPG (Report Program Generator) The only high-level language in common use, RPG was a declarative language primarily for specifying accounting reports and is still in use on IBM's midrange System i. Basic RPG required at least 4K memory locations.
• Symbolic Programming System, SPS-1 and SPS-2, assemblers^[4]. SPS-1 could run on a low end machine with 1.4K memory locations, SPS-2 required at least 4K memory locations.

For the IBM Catalog of 1401 software, see IBM 1400 series. Autocoder was possibly the first primitive compiler. ... FARGO (Fourteen-o-one Automatic Report Generation Operation) was the predecessor to the popular RPG programming language (RPG). ... Fortran (previously FORTRAN[1]) is a general-purpose[2], procedural,[3] imperative programming language that is especially suited to numeric computation and scientific computing. ... In computer programming, a P-code machine or pseudo-code machine is a specification of a cpu whose instructions are expected to be executed in software rather than in hardware (ie, interpreted). ... Fortran (also FORTRAN) is a statically typed, compiled, programming language originally developed in the 1950s and still heavily used for scientific computing and numerical computation half a century later. ... Magnetic disk storage was a critical component of the computer revolution. ... RPG is a native programming language for IBMs iSeries servers - the latest generation of midrange servers which included System/38, System/36, AS/400, iSeries and System i5 systems. ... i5 Model 570 (2006) The Application System/400 (also known as AS/400), now System i (also known as iSeries), is a type of minicomputer produced by IBM. It was first produced in 1988. ... The IBM 1400 series was a family of mid-range buisiness computers that IBM sold in the early 1960s as a replacement for unit record equipment. ...

Character and Op codes

The table below is listed in Character Collating Sequence. This article needs cleanup. ...

Note: If Wordmark bit is set, then the C bit will be opposite of shown. Of course, the C bit was determined and checked automatically by the machine - normally it was of no concern to the programmers. The only way the C bit could be entered was by manually using the switches on the maintenance panel. Although this panel was mainly for use by CEs, a programmer might use these switches to make quick patches while debugging.

An example of a Web browser (Internet Explorer 7) A Web browser is a software application that enables a user to display and interact with text, images, and other information typically located on a Web page at a website on the World Wide Web or a local area network. ... In computing and electronic systems, Binary-coded decimal (BCD) is an encoding for decimal numbers in which each digit is represented by its own binary sequence. ...

Hardware implementation

Most of the logic circuitry of the 1401 was a type of diode-transistor logic (DTL), that IBM referred to as CTDL. Other IBM circuit types used were referred to as: Alloy (some logic, but mostly various non-logic functions, named for the kind of transistors used), CTRL (a type of resistor-transistor logic (RTL)). Later upgrades (e.g., the TAU-9 tape interface) used a faster type of DTL using "drift" transistors (a type of transistor invented by Herbert Kroemer in 1953) for their speed, that IBM referred to as SDTDL. Typical logic levels of these circuits were (S & U Level): high – 0V to -0.5V, low – -6V to -12V; (T Level): high – 6V to 1V, low – -5.5V to -6V. Diode-Transistor Logic (DTL) Diode-Transistor Logic, or DTL, refers to the technology for designing and fabricating digital circuits wherein logic gates employ both diodes and transistors. ... Resistor-transistor logic (RTL) is a class of digital circuits built from bipolar junction transistors (BJT), and resistors; it is the earliest transistorized digital logic used. ... The drift-field transistor, also called the drift transistor or graded base transistor, is a type of high-speed bipolar junction transistor having a doping-engineered electric field in the base to reduce the charge carrier base transit time. ... Herbert Kroemer (born August 25, 1928) is a Professor of Electrical and Computer Engineering at University of California, Santa Barbara, received a Ph. ... Year 1953 (MCMLIII) was a common year starting on Thursday (link will display full calendar) of the Gregorian calendar. ...

These circuits were constructed of individual discrete components mounted on single sided paper-epoxy printed circuit boards either 2.5 by 4.5 inches (38 by 114 mm) with a 16 pin gold plated edge connector (single wide) or 5.375 by 4.5 inches (82 by 114 mm) with two 16 pin gold plated edge connectors (double wide), that IBM referred to as SMS cards (Standard Modular System). The amount of logic on one card was similar to that in one 7400 series SSI or simpler MSI package (e.g., 3 to 5 logic gates or a couple of flip-flops on a single wide card up to about 20 logic gates or 4 flip-flops on a double wide card). Close-up photo of one side of a motherboard PCB, showing conductive traces, vias and solder points for through-hole components on the opposite side. ... GOLD refers to one of the following: GOLD (IEEE) is an IEEE program designed to garner more student members at the university level (Graduates of the Last Decade). ... GOLD refers to one of the following: GOLD (IEEE) is an IEEE program designed to garner more student members at the university level (Graduates of the Last Decade). ... The Standard Modular System (SMS) was a system of standard transistorized circuit boards developed by IBM in the late 1950s, originally for the IBM 7030, then used in their computers and peripherals until the middle 1970s. ... The 7400 chip, containing four NANDs. ... Integrated circuit of Atmel Diopsis 740 System on Chip showing memory blocks, logic and input/output pads around the periphery Microchips with a transparent window, showing the integrated circuit inside. ... Integrated circuit of Atmel Diopsis 740 System on Chip showing memory blocks, logic and input/output pads around the periphery Microchips with a transparent window, showing the integrated circuit inside. ...

These boards were inserted in sockets on racks, that IBM referred to as gates.

Art Inspired by IBM 1401

In October of 2006, respected indie label 4AD (The Pixies, Dead Can Dance, Scott Walker) put out an album by Icelandic avante-garde musician, Jóhann Jóhannsson. The album is called 'IBM 1401, A User's Manual'. The concept is based upon work his father, Jóhann Gunnarsson, chief maintenance engineer of one of the country’s first computers, and Elias Davidsson, one of the first programmers in the country, did back in 1964. The album was originally written for a string quartet, organ and electronics and to accompany a dance piece by long-standing collaborator friend, Erna Ómarsdóttir. For the album recording, Johann has rewritten it for a sixty-piece string orchestra, adding a new final movement and incorporating electronics and vintage reel-to-reel recordings of a singing IBM 1401 mainframe computer found in his father’s attic. The result is quite astonishing. Link to mp3 samples from the album. This article is about the record label 4AD. For the year, see 4. ... The Pixies are an American alternative rock music group formed in Boston, Massachusetts in 1986. ... Dead Can Dance is a band comprising Lisa Gerrard and Brendan Perry. ... Scott Walker is the stage name of the American singer-songwriter Noel Scott Engel (born 9 January 1943 in Hamilton, Ohio). ... Jóhann Jóhannsson is an Icelandic-born musician, composer and producer. ...

An early Jim Henson Muppet sketch appears to parody a technical training manual. A prototype of Cookie Monster, with sharper teeth, consumes a complex machine while it reads its own instruction manual aloud. Youtube Video [1]. Jim Henson (September 24, 1936 – May 16, 1990) was the most widely known American puppeteer in modern American television history. ... John Denver and the Muppets: A Christmas Together The Muppets are a group of puppets and costume characters created by Jim Henson and the company he created. ... Cookie Monster (right) and his mother in a season 33 Letter of the Day segment, 2002. ...

References

• IBM (April, 1966). IBM 1401 System Summary. A24-1401-1. Brief descriptions of the machine features, componets, configurations, and special features
• IBM (April, 1962). IBM 1401 Data Processing System: Reference Manual. A24-1403-5.

External links

• IBM 1401 documents on bitsavers.org
• IBM Archives, 1401 Data Processing System
• IBM 1401 videos and sounds
• 1401s I have Known, Tom Van Vleck
• Haines, L. H. (1965). "Serial compilation and the 1401 FORTRAN compiler". IBM Systems Journal 4 (1): 73-80. . This article was reprinted, edited, in both editions of Lee, John A. N. (1967(1st), 1974(2nd)). Anatomy of a Compiler. Van Nostrand Reinhold.
• Official 4AD page for Johann Johannsson's concept album "IBM 1401: A User's Manual"
• "The Real Computer Monster" (video)
• Music inspired by IBM 1401

Notes

1. ^ 1401 Restoration Project.
2. ^ IBM (April 1962). IBM 1401 Data Processing System: Reference Manual, A24-1403-5, pg 15. “The use of the variable-length instruction and data format requires a method of determining the instruction and data-word length. This identification is provided by a word mark.”
3. ^ K is used in this article for 1000, not 1024.
4. ^ The History of Programming Languages: SPS web page has, at the bottom, the assertion, attributed to Ray Saunders, that SPS was "was field-written by IBM CEs and SEs".