IBM 7070 is a decimal-architecture intermediate data-processing system that was introduced by

IBM International Business Machines Corporation (using the trademark IBM), nicknamed Big Blue, is an American Multinational corporation, multinational technology company headquartered in Armonk, New York, and present in over 175 countries. It is ...

in 1958. It was part of the

IBM 700/7000 series The IBM 700/7000 series is a series of large-scale (Mainframe computer, mainframe) computer systems that were made by IBM through the 1950s and early 1960s. The series includes several different, incompatible processor architectures. The 700s ...

, and was based on discrete

transistor A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch electrical signals and electric power, power. It is one of the basic building blocks of modern electronics. It is composed of semicondu ...

s rather than the

vacuum tube A vacuum tube, electron tube, thermionic 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 voltage, potential difference has been applied. It ...

s of the 1950s. It was the company's first transistorized

stored-program computer A stored-program computer is a computer that stores program instructions in electronically, electromagnetically, or optically accessible memory. This contrasts with systems that stored the program instructions with plugboards or similar mechani ...

The 7070 was expected to be a "common successor to at least the 650 and the 705". The 7070 was not designed to be compatible with the 650 instruction set, as the latter had a second jump address in every instruction to allow optimal use of the drum, something unnecessary and wasteful in a computer with random-access

core memory Core or cores may refer to: Science and technology * Core (anatomy), everything except the appendages * Core (laboratory), a highly specialized shared research resource * Core (manufacturing), used in casting and molding * Core (optical fiber), ...

. As a result, a simulator was needed to run old programs. The 7070 was also marketed as an IBM 705 upgrade, but failed miserably due to its incompatibilities, including an inability to fully represent the 705 character set; forcing IBM to quickly introduce 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 ...

as a "transistorized IBM 705" that was fully compatible. The 7070 series stored data in words containing 10 decimal digits plus a sign. Digits were encoded using a two-out-of-five code. Characters were represented by a two-digit code. The machine shipped with 5,000 or 9,990 words of core memory and the CPU speed was about 27KIPS. A typical system was leased for $17,400 per month or could be purchased for $813,000. The 7070 weighed . Later systems in this series were the faster IBM 7074 introduced in July 1960 and the IBM 7072 (1961), a less expensive system using the slower 7330 instead of 729 tape drives. The 7074 could be expanded to 30K words. They were eventually replaced by the

System/360 The IBM System/360 (S/360) is a family of mainframe computer systems announced by IBM on April 7, 1964, and delivered between 1965 and 1978. System/360 was the first family of computers designed to cover both commercial and scientific applicati ...

, announced in 1964.

Architecture

The 7070 is word addressable but many instructions can specify a range of digits. It has a single address space for registers and core storage. It has three accumulators and 99 index words. IBM numbers digits starting with 0 for the most significant digit. Instructions on the 7070 typically have a signed two-digit opcode, a two-digit index field, a two-digit control field and a four-digit address field. In many instruction the control field is used as a field definition. The 7070 uses Record Definition Words (RDWs) for #Block transmission #Input/Output #Table lookup A minus sign indicates the last RDW in a list; an alpha sign is invalid. Each RDW contains the starting and ending address for a block.

Hardware implementation

The 7070 was implemented using both CTDL (in the logic and control sections) and current-mode logic (in the timing storage and core storage sections) on Standard Modular System (SMS) cards. A total of about 30,000 alloy-junction germanium transistors and 22,000 germanium diodes are used, on approximately 14,000 SMS cards.

Input/Output in original announcement

The 7070, 7072 and 7074 support a variety of peripheral devices. including up to 1 7150 console typewriter, 4 7300 Disk-Storage units attached to an IBM 7604 Tape Control via an IBM 7605 RAMAC Control, 40 729 models II and IV tape drives attached to an IBM 7604 Tape Control, and 6 (3 input, 3 output) unit record devices attached to an IBM 7603 Input/Output Synchronizer via an IBM 7600 Input/Output control.

Mode of operation

Every I/O operation uses a list of Record Definition Words (RDWs); the last RDW in the list has a minus sign. Each RDW has a beginning and ending address. Ten 729 tape drives can be attached to each of 4 I/O channels. Four 7300 disk drives can be attached to the first two channels. The channels run asynchronously to the processor and generate priority interrupts upon completion of an operation. Unit-record devices (Card readers, printers, punches) are connected to a 7600 Input/Output control via a 7603 synchronizer that buffers cards and print lines. Completion of a transfer between the device and the buffer generates a priority interrupt. Transfers between the buffer and core storage delay the processor until completion. Transfers are limited to 16 words. The 7150 console and 7501 console card reader are connected directly to the 7600 Input/Output control

729 Tape drives

The IBM 729 is a 7-track tape drive common to most of the IBM 14xx and 70xx computers. It is available as a model II and a faster model IV. The models II and IV normally record at 556 BPI, but they support 200 BPI for compatibility with the older IBM 727 and 729 model I. The models V and VI, supporting 800 BPI, were announced later. The 729 is not used on the 7072.

7150 Console control unit

The 7150 includes a console typewriter that both controls the system and communicates with the running program via the 7600 I/O control.

7151 console card reader

The 7151 console card reader is a modified

keypunch A keypunch is a device for precisely punching holes into stiff paper cards at specific locations as determined by keys struck by a human operator. Other devices included here for that same function include the gang punch, the pantograph punch, ...

that can only read.

7300 Disk Storage Units

The IBM 7300 Disk Storage Unit has a capacity of 6 million digits. The IBM 1301 replaced it in 1961.

7330 Tape drive

The IBM 7330 is a slower, less expensive, alternative to the 729; it is not used on the 7070 or 7074. Like the 729 II and IV, the 7330 supports dual (200 BPI/556 BPI) density.

7400 Printer

Up to three 7400 Printers can be attached to the 7603 Input/Output Synchronizer. The 7400 prints 120 column lines at up to 150 lines per minute. The installation must wire a

plugboard A plugboard or control panel (the term used depends on the application area) is an array of jack (connector), jacks or sockets (often called hubs) into which patch cords can be inserted to complete an electrical circuit. Control panels are som ...

to control the layout of the print line.

7500 Card reader

Up to three 7500 Card readers can be attached to the 7603 Input/Output Synchronizer. The 7500 reads 80-column cards at up to 500 cards per minute. The installation must wire a

to control the layout of the cards.

7550 Card punch

Up to three 7550 Card punches can be attached to the 7603 Input/Output Synchronizer. The 7550 punches 80-column cards at up to 250 cards per minute. The installation must wire a

to control the layout of the cards.

Additional or optional I/O units

7907 Data Channel

The 7907 is an 8-bit channel with the same interface as the 7908 and 7909 channels on the 7080 and 7090.

1301 and 1302 Disk storage

In 1961, IBM announced the IBM 1301-1 Disk Storage Unit, with a capacity of 28 million characters per module, replacing the IBM 7300 Disk Storage Units. The 1301 attaches to an IBM 7907 Data Channel via an IBM 7631-II File Control. In 1963, IBM announced the IBM 1302, with quadruple the capacity of the 1301.

7340 Hypertape

In 1961, IBM announced the IBM 7340 Hypertape. The 7340 attaches to an IBM 7907 Data Channel via an IBM 7640 Hypertape Control.

1414 I/O Synchronizer

* IBM 1414-6 Input-Output Synchronizer contains 6 buffers and can attach a variety of serial I/O devices: ** 1009 Data Transmission Unit (modem) ** 1011 Paper Tape Reader ** 1014 Remote Enquiry Units (keyboards and typewriter) ** Telegraph I/O units The 1414-6 is connected to 7070/7074 via the IBM 7907 Data Channel Switch. The 7907 can execute channel programs from the main memory of the 7070.

Notes

References

External links

The IBM 7070
Experiences of one user,

Tom Van Vleck Tom Van Vleck is an American computer software engineer. Life and work Van Vleck graduated from MIT in 1965 with a BS in Mathematics. He worked on CTSS at MIT, and co-authored its first email program with Noel Morris. In 1965, he joined Project ...

BIRTH OF AN UNWANTED IBM COMPUTER Computer History Vignettes
by

Bob Bemer Robert William Bemer (February 8, 1920 – June 22, 2004) was a computer scientist best known for his work at IBM during the late 1950s and early 1960s. Early life and education Born in Sault Ste. Marie, Michigan, Bemer graduated from Cranbro ...

IBM 7070 documentation
on Bitsavers.org

– Includes a cross assembler for the IBM 7070/7074
IBM 7070 film
*{{cite book , first = Martin H. , last = Weik , title = A Third Survey of Domestic Electronic Digital Computing Systems: IBM 7070 Section , publisher = Ballistic Research Laboratories (BRL) , date = March 1961 , id = Report No. 1115 , url = http://ed-thelen.org/comp-hist/BRL61-ibm7070.html#IBM-7070 Contains about 10 pages of IBM 7070 survey detail: applications, customers, specifications, and costs.
Cover of IBM 7070 brochure
at Classic Computer Brochures 7070 7 7070 Computer-related introductions in 1959 Decimal computers