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The IBM 700/7000 series is a series of large-scale (
mainframe A mainframe computer, informally called a mainframe or big iron, is a computer used primarily by large organizations for critical applications like bulk data processing for tasks such as censuses, industry and consumer statistics, enterpr ...
) computer systems that were made by IBM through the 1950s and early 1960s. The series includes several different, incompatible processor architectures. The 700s use
vacuum-tube A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied. The type known as a ...
logic and were made obsolete by the introduction of the
transistorized upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch e ...
7000s. The 7000s, in turn, were eventually replaced with System/360, which was announced in 1964. However the 360/65, the first 360 powerful enough to replace 7000s, did not become available until November 1965. Early problems with
OS/360 OS/360, officially known as IBM System/360 Operating System, is a discontinued batch processing operating system developed by IBM for their then-new System/360 mainframe computer, announced in 1964; it was influenced by the earlier IBSYS/IBJ ...
and the high cost of converting software kept many 7000s in service for years afterward.


Architectures

The IBM 700/7000 series has six completely different ways of storing data and instructions: *First scientific (36/18-
bit The bit is the most basic unit of information in computing and digital communications. The name is a portmanteau of binary digit. The bit represents a logical state with one of two possible values. These values are most commonly represente ...
words): 701 (Defense Calculator) *Later scientific (36-bit words, hardware floating-point): 704, 709, 7040, 7044, 7090, 7094 *Commercial (variable-length character strings): 702, 705, 7080 * 1400 series (variable-length character strings): 7010 *Decimal (10-digit words): 7070, 7072, 7074 *Supercomputer (64-bit words): 7030 "Stretch" The 700 class use vacuum tubes, the 7000 class is
transistorized upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch e ...
. All machines (like most other computers of the time) use magnetic core memory; except for early 701 and 702 models, which initially used
Williams tube The Williams tube, or the Williams–Kilburn tube named after inventors Freddie Williams and Tom Kilburn, is an early form of computer memory. It was the first random-access digital storage device, and was used successfully in several early c ...
CRT memory and were later converted to magnetic core memory.


Software compatibility issues

Early computers were sold without software. As operating systems began to emerge, having four different mainframe architectures plus the
1400 Year 1400 ( MCD) was a leap year starting on Thursday (link will display the full calendar) of the Julian calendar. The year 1400 was not a leap year in the Proleptic Gregorian calendar. Events January–December * Henry IV of England ...
midline architectures became a major problem for IBM since it meant at least four different programming efforts were required. The System/360 combines the best features of the 7000 and 1400 series architectures into a single design both for commercial computing and for scientific and engineering computing. However, its architecture is not compatible with those of the 7000 and 1400 series, so some 360 models have optional features that allow them to emulate the 1400 and 7000 instruction sets in microcode. One of the selling points of the
System/370 The IBM System/370 (S/370) is a model range of IBM mainframe computers announced on June 30, 1970, as the successors to the System/360 family. The series mostly maintains backward compatibility with the S/360, allowing an easy migration path ...
, the successor of the 360 introduced in mid-1970, was improved 1400/7000 series emulation, which could be done under operating system control rather than shutting down and restarting in emulation mode as was required for emulation of 7040/44, 7070/72/74, 7080 and 7090/94 on all of the 360s except the 360/85.


Peripherals

While the architectures differ, the machines in the same class use the same electronics technologies and generally use the same peripherals. Tape drives generally use 7-track format, with the IBM 727 for vacuum tube machines and the 729 for transistor machines. Both the vacuum tube and most transistor models use the same card readers, card punches, and
line printer A line printer prints one entire line of text before advancing to another line. Most early line printers were impact printers. Line printers are mostly associated with unit record equipment and the early days of digital computing, but the ...
s that were introduced with the 701. These units, the IBM 711, 721, and 716, are based on IBM accounting machine technology and even include
plugboard A plugboard or control panel (the term used depends on the application area) is an array of jacks or sockets (often called hubs) into which patch cords can be inserted to complete an electrical circuit. Control panels are sometimes used to d ...
control panels. They are relatively slow and it was common for 7000 series installations to include an
IBM 1401 The IBM 1401 is a variable-wordlength decimal computer that was announced by IBM on October 5, 1959. The first member of the highly successful IBM 1400 series, it was aimed at replacing unit record equipment for processing data stored on pun ...
, with its much faster peripherals, to do card-to-tape and tape-to-line-printer operations off-line. Three later machines, the 7010, the 7040 and the 7044, adopted peripherals from the midline IBM 1400 series. Some of the technology for the 7030 was used in data channels and peripheral devices on other 7000 series computers, e.g., 7340 Hypertape.


First scientific architecture (701)

Known as the Defense Calculator while in development in the IBM Poughkeepsie Laboratory, this machine was formally unveiled April 7, 1953 as the IBM 701 Electronic Data Processing Machine. ;Data formats Numbers are either 36 bits or 18 bits long, only fixed point. *Fixed-point numbers are stored in binary sign/magnitude format. ;Instruction format Instructions are 18 bits long, single address. *Sign (1 bit) – Whole-word (-) or Half-word (+) operand address *Opcode (5 bits) – 32 instructions *Address (12 bits) – 4096 Half-word addresses To expand the memory from 2048 to 4096 words, a 33rd instruction was added that uses the most-significant bit of its address field to select the bank. (This instruction was probably created using the "No OP" instruction, which appears to have been the only instruction with unused bits, as it originally ignored its address field. However, documentation on this new instruction is not currently available.) ;Registers Processor registers consisted of: *AC  – 38-bit Accumulator *MQ – 36-bit Multiplier-Quotient ;Memory 2,048 or 4,096 – 36-bit binary words with six-bit characters


Later scientific architecture (704/709/7090/7094)

IBM's 36-bit scientific architecture was used for a variety of computation-intensive applications. First machines were the vacuum-tube 704 and 709, followed by the transistorized 7090, 7094, 7094-II, and the lower-cost 7040 and 7044. The ultimate model was the Direct Coupled System (DCS) consisting of a 7094 linked to a 7044 that handled input and output operations. ;Data formats Numbers are 36 bits long, both fixed point and floating point. *Fixed-point numbers are stored in binary sign/magnitude format. *Single-precision
floating-point In computing, floating-point arithmetic (FP) is arithmetic that represents real numbers approximately, using an integer with a fixed precision, called the significand, scaled by an integer exponent of a fixed base. For example, 12.345 can ...
numbers have a magnitude sign, an 8-bit excess-128 exponent and a 27-bit magnitude *Double-precision floating-point numbers, introduced on the 7094, have a magnitude sign, a 17-bit excess-65536 exponent, and a 54-bit magnitude * Alphameric characters are 6-bit BCD, packed six to a word. ;Instruction format The basic instruction format is a three-bit ''prefix'', fifteen-bit ''decrement'', three-bit ''tag'', and fifteen-bit ''address''. The prefix field specifies the class of instruction. The decrement field often contains an immediate operand to modify the results of the operation, or is used to further define the instruction type. The three bits of the tag specify three (seven in the 7094) ''
index register An index register in a computer's CPU is a processor register (or an assigned memory location) used for pointing to operand addresses during the run of a program. It is useful for stepping through strings and arrays. It can also be used for ho ...
s'', the contents of which are ''subtracted'' from the address to produce an ''effective address''. The address field either contains an address or an immediate operand. ;Registers Processor registers consisted of: *AC  – 38-bit Accumulator *MQ – 36-bit Multiplier-Quotient *XR  – 15-bit Index Registers (three or seven) *SI    – 36-bit Sense Indicator The accumulator (and multiplier-quotient) registers operate in sign/magnitude format. The Index registers operate using
two's complement Two's complement is a mathematical operation to reversibly convert a positive binary number into a negative binary number with equivalent (but negative) value, using the binary digit with the greatest place value (the leftmost bit in big- endian ...
format and when used to modify an instruction address are ''subtracted'' from the address in the instruction. On machines with three index registers, if the tag has two or three bits set (i.e. selected multiple registers) then their values are ORed together before being subtracted. The IBM 7094, with seven index registers has a "compatibility" mode to permit programs from earlier machines that used this trick to continue to be used. The Sense Indicators permit interaction with the operator via panel switches and lights. ;Memory *704: 4,096 or 8,192 or 32,768 – 36-bit binary words with six-bit characters *709, 7090, 7094, 7094 II, 7040, 7044: 32,768 – 36-bit binary words with six-bit characters ;Input/output The 709/7090 series use Data Synchronizer Channels for high speed input/output, such as tape and disk. The basic 7-bit DSCs, e.g., 7607, execute their own simple programs from the computer memory that controls the transfer of data between memory and the I/O devices; the more advanced 9-bit 7909 supports more sophisticated channel programs. Because the
unit record equipment Starting at the end of the nineteenth century, well before the advent of electronic computers, data processing was performed using electromechanical machines collectively referred to as unit record equipment, electric accounting machines (EAM) o ...
on the 709x was so slow,
Punched card A punched card (also punch card or punched-card) is a piece of stiff paper that holds digital data represented by the presence or absence of holes in predefined positions. Punched cards were once common in data processing applications or to di ...
I/O and high-speed printing were often performed by transferring magnetic tapes to and from an off-line
IBM 1401 The IBM 1401 is a variable-wordlength decimal computer that was announced by IBM on October 5, 1959. The first member of the highly successful IBM 1400 series, it was aimed at replacing unit record equipment for processing data stored on pun ...
. Later, the data channels were used to connect a 7090 to a 7040 or a 7094 to a 7044 to form the IBM 7094/7044 Direct Coupled System (DCS). In that configuration, the 7044, which could use faster 1400 series peripherals, primarily handled I/O.


FORTRAN assembly program

The FORTRAN Assembly Program (FAP) is an assembler for the 709, 7090, and 7094 under IBM's makeshift FMS (
Fortran Monitor System The history of IBM mainframe operating systems is significant within the history of mainframe operating systems, because of IBM's long-standing position as the world's largest hardware supplier of mainframe computers. IBM mainframes run operatin ...
) and
IBSYS IBSYS is the discontinued tape-based operating system that IBM supplied with its IBM 709, IBM 7090 and IBM 7094 computers. A similar operating system (but with several significant differences), also called IBSYS, was provided with IBM 7040 and ...
operating systems. An earlier assembler was SCAT (SHARE Compiler-Assembler-Translator). Macros were added to FAP by Bell Laboratories (BE-FAP), and the final 7090/7094 assembler was IBMAP, under IBSYS/IBJOB. Its pseudo-operation ''BSS'', used to reserve memory, is the origin of the common name of the " BSS section", still used in many
assembly language In computer programming, assembly language (or assembler language, or symbolic machine code), often referred to simply as Assembly and commonly abbreviated as ASM or asm, is any low-level programming language with a very strong correspondence b ...
s today for designating reserved
memory address In computing, a memory address is a reference to a specific memory location used at various levels by software and hardware. Memory addresses are fixed-length sequences of digits conventionally displayed and manipulated as unsigned integers. ...
ranges of the type not having to be saved in the
executable In computing, executable code, an executable file, or an executable program, sometimes simply referred to as an executable or binary, causes a computer "to perform indicated tasks according to encoded instructions", as opposed to a data fil ...
image.


Commercial architecture (702/705/7080)

The
IBM 702 The IBM 702 was an early generation tube-based digital computer produced by IBM in the early to mid-1950s. It was the company's response to Remington Rand's UNIVAC—the first mainframe computer to use magnetic tapes. As these machines were ...
and IBM 705 are similar, and the 705 can run many 702 programs without modification, but they are not completely compatible. The
IBM 7080 The IBM 7080 was a variable word length BCD transistor computer in the IBM 700/7000 series commercial architecture line, introduced in August 1961, that provided an upgrade path from the vacuum tube IBM 705 computer. The 7080 weighed about . ...
is a transistorized version of the 705, with various improvements. For backward compatibility it can be run in ''705 I'' mode, ''705 II'' mode, ''705 III'' mode, or full 7080 mode. ;Data format Data is represented by a variable-length string of characters terminated by a Record mark. ;Instruction format Five characters: one character opcode and four character address – OAAAA ;Registers *702 **two Accumulators (A & B) – 512 characters *705 **one Accumulator – 256 characters **14 auxiliary storage units – 16 characters **one auxiliary storage unit – 32 characters *7080 **one Accumulator – 256 characters **30 auxiliary storage units – 512 characters **32 communication storage units – 8 characters ;Memory *702 **2,000 to 10,000 characters in
Williams tube The Williams tube, or the Williams–Kilburn tube named after inventors Freddie Williams and Tom Kilburn, is an early form of computer memory. It was the first random-access digital storage device, and was used successfully in several early c ...
s (in increments of 2,000 characters) **Character cycle rate – 23 microseconds *705 (models I, II, or III) **20,000 or 40,000 or 80,000 characters of core memory **Character cycle rate – 17 microseconds or 9.8 microseconds *7080 **80,000 or 160,000 characters of Core memory **Character cycle rate – 2.18 microseconds ;Input/output The 705 and the basic 7080 use channels with a 7-bit interface. The 7080 can be equipped with 7908 data channels to attach faster devices using a 9-bit interface.


1400 series architecture (7010)

The 700/7000 commercial architecture inspired the very successful
IBM 1400 series The IBM 1400 series were second-generation ( transistor) mid-range business decimal computers that IBM marketed in the early 1960s. The computers were offered to replace tabulating machines like the IBM 407. The 1400-series machines stored infor ...
of mid-sized business computers. In turn, IBM later introduced a mainframe version of the
IBM 1410 The IBM 1410, a member of the IBM 1400 series, was a decimal computer with variable word length that was announced by IBM on September 12, 1960 and marketed as a midrange business computer. It was withdrawn on March 30, 1970. Overview The 1410 ...
called the IBM 7010. ;Data format *Data is represented by a variable length string of characters terminated by a word mark. ;Instruction format *Variable length: 1, 2, 6, 7, 11, or 12 characters. ;Registers Fifteen five-character fields in fixed locations in low memory can be treated as index registers, whose values can be added to the address specified in an instruction. Also, certain internal registers that would today be invisible, such as the addresses of the characters being currently processed, are exposed to the programmer; in particular, the B address register is often used for subroutine linkage. ;Memory *100,000 characters


Decimal architecture (7070/7072/7074)

The
IBM 7070 IBM 7070 was a decimal-architecture intermediate data-processing system that was introduced by IBM in 1958. It was part of the IBM 700/7000 series, and was based on discrete transistors rather than the vacuum tubes of the 1950s. It was the compan ...
, IBM 7072, and IBM 7074 are decimal, fixed-word-length machines. They use a ten-digit word like the smaller and older
IBM 650 The IBM 650 Magnetic Drum Data-Processing Machine is an early digital computer produced by IBM in the mid-1950s. It was the first mass produced computer in the world. Almost 2,000 systems were produced, the last in 1962, and it was the firs ...
, but are not
instruction set In computer science, an instruction set architecture (ISA), also called computer architecture, is an abstract model of a computer. A device that executes instructions described by that ISA, such as a central processing unit (CPU), is called ...
compatible with the 650. ;Data format *Word length – 10 decimal digits plus sign *Digit encoding –
two-out-of-five code A two-out-of-five code is a constant-weight code that provides exactly ten possible combinations of two bits, and is thus used for representing the decimal digits using five bits. Each bit is assigned a weight, such that the set bits sum to th ...
*Floating point – optional, with a two-digit exponent *Three signs for each word – Plus, Minus, and Alpha **Plus and Minus indicate 10-digit numeric values **Alpha indicates five characters of text coded by pairs of digits. 61 = A, 91 = 1. ;Instruction format *All instructions use one word *Two-digit
opcode In computing, an opcode (abbreviated from operation code, also known as instruction machine code, instruction code, instruction syllable, instruction parcel or opstring) is the portion of a machine language instruction that specifies the opera ...
(including sign, Plus or Minus only) *Two-digit index register *Two-digit field control – allows selecting sets of digits, shifting left or right *Four-digit address ;Registers *All registers use one word and can also be addressed as memory. *Accumulators – three (addresses 9991, 9992, and 9993 – standard; 99991, 99992, and 99993 – extended 7074) *Program register – one (address 9995 – standard; 99995 – extended 7074) **Addressable from console only. Stores current instruction. *Instruction counter – one (address 9999 – standard; 99999 – extended 7074) **Addressable from console only *Index registers – 99 (addresses 0001-0099) ;Memory *5000 to 9990 words (standard) *15000 to 30000 words (extended 7074) *Access time – 6 microseconds (7070/7072), 4 microseconds (7074) *Add time – 72 microseconds (7070), 12 microseconds (7072), 10 microseconds (7074) ;Input/output The 707x uses channels with a 7-bit interface. The 7070 and 7074 can be equipped with 7907 data channels to attach faster devices using a 9-bit interface.


Timeline

An IBM 7074 was used by the U.S.
Internal Revenue Service The Internal Revenue Service (IRS) is the revenue service for the United States federal government, which is responsible for collecting U.S. federal taxes and administering the Internal Revenue Code, the main body of the federal statutory tax ...
in 1962. The
IBM 7700 Data Acquisition System The IBM 7700 Data Acquisition System was announced by IBM on December 2, 1963. It is capable of collecting data from as many as 32 sources simultaneously, process the data and transmit results to up to 16 remote printers, display units or plot boa ...
is not a member of the IBM 7000 series, despite its number and its announcement date of December 2, 1963.


Performance

All of the 700 and 7000 series machines predate standard performance measurement tools such as the Whetstone (1972),
Dhrystone Dhrystone is a synthetic computing benchmark program developed in 1984 by Reinhold P. Weicker intended to be representative of system (integer) programming. The Dhrystone grew to become representative of general processor (CPU) performance. Th ...
(1984), LINPACK (1979), or Livermore loops (1986) benchmarks. In the table below, the Gibson and Knight measurements report speed, where higher numbers are better; the TRIDIA measurement reports time, where lower numbers are better.


See also

*
IBM 650 The IBM 650 Magnetic Drum Data-Processing Machine is an early digital computer produced by IBM in the mid-1950s. It was the first mass produced computer in the world. Almost 2,000 systems were produced, the last in 1962, and it was the firs ...


Notes


References


External links


IBM Mainframe family treeThe Architecture of IBM's Early Computers
(PDF)

* ttp://www-1.ibm.com/ibm/history/exhibits/mainframe/mainframe_PP705.html IBM 705* ttp://www.brouhaha.com/~eric/retrocomputing/ibm/stretch/ IBM 7030 Stretchbr>IBM 7070Birth of an Unwanted IBM Computer, by Bob Bemer


Reference manuals

;701 : ;702 : ;704 : ;705 : ;7010 : ;7030 : ;7040/7044 : ;7070/7072/7074 : ;7080 : ;7090/7094 : : {{DEFAULTSORT:IBM 700 7000 series Series Series