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 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 log ...

, 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 ...

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 ...

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 __NOTOC__ Year 650 ( DCL) was a common year starting on Friday (link will display the full calendar) of the Julian calendar. The denomination 650 for this year has been used since the early medieval period, when the Anno Domini calendar era bec ...

, 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 centr ...

. 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 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 the ...

. 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 applic ...

, 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 (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 Disk Storage Unit had a capacity of 6 million digits. From 1961: the IBM 1301-1 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
BIRTH OF AN UNWANTED IBM COMPUTER Computer History Vignettes
by Bob Bemer
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