Women holding parts of the first four Army computers

The BRLESC I (Ballistic Research Laboratories Electronic Scientific Computer) was one of the last of the first-generation electronic computers. It was built by the

United States Army The United States Army (USA) is the primary Land warfare, land service branch of the United States Department of Defense. It is designated as the Army of the United States in the United States Constitution.Article II, section 2, clause 1 of th ...

Ballistic Research Laboratory The Ballistic Research Laboratory (BRL) was a research facility under the U.S. Army Ordnance Corps and later the U.S. Army Materiel Command that specialized in ballistics as well as vulnerability and lethality analysis. Situated at Aberdeen Pr ...

(BRL) at

Aberdeen Proving Ground Aberdeen Proving Ground (APG) is a U.S. Army facility located adjacent to Aberdeen, Harford County, Maryland, United States. More than 7,500 civilians and 5,000 military personnel work at APG. There are 11 major commands among the tenant units, ...

with assistance from the National Bureau of Standards (now the

National Institute of Standards and Technology The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into Outline of p ...

), and was designed to take over the computational workload of

EDVAC EDVAC (Electronic Discrete Variable Automatic Computer) was one of the earliest electronic computers. It was built by Moore School of Electrical Engineering at the University of Pennsylvania. Along with ORDVAC, it was a successor to the ENIAC. ...

and ORDVAC, which themselves were successors of

ENIAC ENIAC (; Electronic Numerical Integrator and Computer) was the first Computer programming, programmable, Electronics, electronic, general-purpose digital computer, completed in 1945. Other computers had some of these features, but ENIAC was ...

. It began operation in 1962. The Ballistic Research Laboratory became a part of the U.S. Army Research Laboratory in 1992. BRLESC was designed primarily for scientific and military tasks requiring high precision and high computational speed, such as

ballistics Ballistics is the field of mechanics concerned with the launching, flight behaviour and impact effects of projectiles, especially weapon munitions such as bullets, unguided bombs, rockets and the like; the science or art of designing and acceler ...

problems, army logistical problems, and weapons systems evaluations. It contained 1727

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 and 853

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 and had a

memory Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembe ...

of 4096 68- bit

word A word is a basic element of language that carries semantics, meaning, can be used on its own, and is uninterruptible. Despite the fact that language speakers often have an intuitive grasp of what a word is, there is no consensus among linguist ...

s. BRLESC employed

punched card A punched card (also punch card or punched-card) is a stiff paper-based medium used to store digital information via the presence or absence of holes in predefined positions. Developed over the 18th to 20th centuries, punched cards were widel ...

magnetic tape Magnetic tape is a medium for magnetic storage made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany in 1928, based on the earlier magnetic wire recording from Denmark. Devices that use magnetic ...

, and a magnetic drum as input-output devices, which could be operated simultaneously. It was capable of five million (bitwise) operations per second. A fixed-point addition took 5 microseconds, a

floating-point In computing, floating-point arithmetic (FP) is arithmetic on subsets of real numbers formed by a ''significand'' (a Sign (mathematics), signed sequence of a fixed number of digits in some Radix, base) multiplied by an integer power of that ba ...

addition took 5 to 10 microseconds, a multiplication (fixed- or floating-point) took 25 microseconds, and a division (fixed- or floating-point) took 65 microseconds. (These times are including the memory access time, which was 4-5 microseconds.) It was the fastest computer in the world until the CDC 6600 was introduced in 1964. BRLESC and its predecessor, ORDVAC, used their own unique notation for

hexadecimal Hexadecimal (also known as base-16 or simply hex) is a Numeral system#Positional systems in detail, positional numeral system that represents numbers using a radix (base) of sixteen. Unlike the decimal system representing numbers using ten symbo ...

numbers. Instead of the sequence A B C D E F universally used today, the digits 10 to 15 were represented by the letters K S N J F L, corresponding to the

teletypewriter A teleprinter (teletypewriter, teletype or TTY) is an electromechanical device that can be used to send and receive typed messages through various communications channels, in both point-to-point and point-to-multipoint configurations. Init ...

characters on five-track paper tape. The

mnemonic A mnemonic device ( ), memory trick or memory device is any learning technique that aids information retention or retrieval in the human memory, often by associating the information with something that is easier to remember. It makes use of e ...

phrase "King Size Numbers Just For Laughs" was used to remember the letter sequence. BRLESC II, using integrated circuits, became operational in November 1967; it was designed to be 200 times faster than ORDVAC.

References

External links

D.K. ARMY ORDNANCE "HISTORICAL MONOGRAPH, ELECTRONIC COMPUTERS WITHIN THE ORDNANCE CORPS"

One-of-a-kind computers United States Army equipment Vacuum tube computers {{compu-hardware-stub