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 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 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 ...

s rather than the

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 voltage, potential difference has been applied. The type kn ...

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 or optically accessible memory. This contrasts with systems that stored the program instructions with plugboards or similar mechanisms. The definition i ...

The 7070 was expected to be a "common successor to at least the 650 and the 705". The 7070 was not designed to be instruction set compatible with the 650, 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 (manufacturing), used in casting and molding * Core (optical fiber), the signal-carrying portion of an optical fiber * Core, the centra ...

. As a result, a simulator was needed to run old programs. The 7070 was also marketed as an

IBM 705 The IBM 700/7000 series is a series of large-scale (mainframe) 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 lo ...

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 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 ...

. Characters were represented by a two-digit code. The machine shipped with 5,000 to 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). They were eventually replaced by the

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

, announced in 1964.

Hardware implementation

The 7070 was implemented using both CTDL (in the logic and control sections) and

current-mode logic Current mode logic (CML), or source-coupled logic (SCL), is a digital design style used both for logic gates and for board-level digital signaling of digital data. The basic principle of CML is that current from a constant current generator is ...

(in the timing storage and core storage sections) on

Standard Modular System The Standard Modular System (SMS) is a system of standard transistorized circuit boards and mounting racks developed by IBM in the late 1950s, originally for the IBM 7030 Stretch. They were used throughout IBM's second-generation computers, peri ...

(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.

Additional or optional I/O units

Disk storage

The

IBM 7300 IBM manufactured magnetic disk storage devices from 1956 to 2003, when it sold its hard disk drive business to Hitachi. Both the hard disk drive (HDD) and floppy disk drive (FDD) were invented by IBM and as such IBM's employees were responsible fo ...

Disk Storage Unit had a capacity of 6 million digits. From 1961: the

IBM 1301 IBM manufactured magnetic disk storage devices from 1956 to 2003, when it sold its hard disk drive business to Hitachi. Both the hard disk drive (HDD) and floppy disk drive (FDD) were invented by IBM and as such IBM's employees were responsible fo ...

-1 Disk Storage Unit which had a capacity of 28 million characters.

IBM 1414 I/O

* 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.

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 Proje ...

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 Cranb ...

IBM 7070 documentation
on Bitsavers.org

– Includes a cross assembler for the IBM 7070/7074 *{{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

Hardware implementation

Additional or optional I/O units

Disk storage

IBM 1414 I/O

See also

References

External links