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 land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, ...

Ballistic Research Laboratory The Ballistic Research Laboratory (BRL) was a leading U.S. Army research establishment situated at Aberdeen Proving Ground, Maryland that specialized in ballistics (interior, exterior, and terminal) as well as vulnerability and lethality analysi ...

(BRL) at

Aberdeen Proving Ground Aberdeen Proving Ground (APG) (sometimes erroneously called Aberdeen Proving ''Grounds'') 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 a ...

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 physical sci ...

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

ORDVAC The ORDVAC (''Ordnance Discrete Variable Automatic Computer)'', is an early computer built by the University of Illinois for the Ballistic Research Laboratory at Aberdeen Proving Ground. A successor to the ENIAC (along with EDVAC built earlier). ...

, which themselves were successors of

ENIAC ENIAC (; Electronic Numerical Integrator and Computer) was the first programmable, electronic, general-purpose digital computer, completed in 1945. There were other computers that had these features, but the ENIAC had all of them in one pac ...

. 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 ranged weapon munitions such as bullets, unguided bombs, rockets or the like; the science or art of designing and a ...

problems, army

logistical Logistics is generally the detailed organization and implementation of a complex operation. In a general business sense, logistics manages the flow of goods between the point of origin and the point of consumption to meet the requirements of ...

problems, and weapons systems evaluations. It contained 1727

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 ...

s and 853

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 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 remembered, ...

of 4096 72-

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 represented ...

word A word is a basic element of language that carries an objective or practical 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 consen ...

s. BRLESC employed

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 ...

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 magnet ...

, and a

magnetic drum Drum memory was a magnetic data storage device invented by Gustav Tauschek in 1932 in Austria. Drums were widely used in the 1950s and into the 1960s as computer memory. For many early computers, drum memory formed the main working memory o ...

as input-output devices, which could be operated simultaneously. It was capable of five million (bitwise) operations per second. A

fixed-point Fixed point may refer to: * Fixed point (mathematics), a value that does not change under a given transformation * Fixed-point arithmetic, a manner of doing arithmetic on computers * Fixed point, a benchmark (surveying) The term benchmark, be ...

addition took 5

microseconds A microsecond is a unit of time in the International System of Units (SI) equal to one millionth (0.000001 or 10−6 or ) of a second. Its symbol is μs, sometimes simplified to us when Unicode is not available. A microsecond is equal to 1000 n ...

, a

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 be r ...

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,

, used their own unique notation for

hexadecimal In mathematics and computing, the hexadecimal (also base-16 or simply hex) numeral system is a positional numeral system that represents numbers using a radix (base) of 16. Unlike the decimal system representing numbers using 10 symbols, hexa ...

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. Initia ...

characters on five-track

paper tape Five- and eight-hole punched paper tape Paper tape reader on the Harwell computer with a small piece of five-hole tape connected in a circle – creating a physical program loop Punched tape or perforated paper tape is a form of data storage ...

. The

mnemonic A mnemonic ( ) device, or memory device, is any learning technique that aids information retention or retrieval (remembering) in the human memory for better understanding. Mnemonics make use of elaborative encoding, retrieval cues, and imager ...

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