Computer programming or coding is the composition of sequences of instructions, called programs, that computers can follow to perform tasks. It involves designing and implementing algorithms, step-by-step specifications of procedures, by writing code in one or more programming languages. Programmers typically use high-level programming languages that are more easily intelligible to humans than machine code, which is directly executed by the central processing unit. Proficient programming usually requires expertise in several different subjects, including knowledge of the application domain, details of programming languages and generic code libraries, specialized algorithms, and formal logic.
Grace Brewster Hopper was an American computer scientist, mathematician, and United States Navy rear admiral. One of the first programmers of the Harvard Mark I computer, she was a pioneer of computer programming. Hopper was the first to devise the theory of machine-independent programming languages, and the FLOW-MATIC programming language she created using this theory was later extended by others to create COBOL, an early high-level programming language still in use today.
A software bug is an error, flaw or fault in the design, development, or operation of computer software that causes it to produce an incorrect or unexpected result, or to behave in unintended ways. The process of finding and correcting bugs is termed "debugging" and often uses formal techniques or tools to pinpoint bugs. Since the 1950s, some computer systems have been designed to detect or auto-correct various software errors during operations.
The IBM 1620 was announced by IBM on October 21, 1959, and marketed as an inexpensive scientific computer. After a total production of about two thousand machines, it was withdrawn on November 19, 1970. Modified versions of the 1620 were used as the CPU of the IBM 1710 and IBM 1720 Industrial Process Control Systems.
BARK was an early electromechanical computer. BARK was built using standard telephone relays, implementing a 32-bit binary machine. It could perform addition in 150 ms and multiplication in 250 ms. It had a memory with 50 registers and 100 constants. It was later expanded to double the memory. Howard Aiken stated in reference to BARK "This is the first computer I have seen outside Harvard that actually works."
The Harvard Mark I, or IBM Automatic Sequence Controlled Calculator (ASCC), was one of the earliest general-purpose electromechanical computers used in the war effort during the last part of World War II.
Howard Hathaway Aiken was an American physicist and a pioneer in computing, being the original conceptual designer behind IBM's Harvard Mark I computer.
The DEUCE was one of the earliest British commercially available computers, built by English Electric from 1955. It was the production version of the Pilot ACE, itself a cut-down version of Alan Turing's ACE.
The APE(X)C, or All Purpose Electronic (X) Computer series was designed by Andrew Donald Booth at Birkbeck College, London in the early 1950s. His work on the APE(X)C series was sponsored by the British Rayon Research Association. Although the naming conventions are slightly unclear, it seems the first model belonged to the BRRA. According to Booth, the X stood for X-company.
The Z1 was a motor-driven mechanical computer designed by Konrad Zuse from 1936 to 1937, which he built in his parents' home from 1936 to 1938. It was a binary electrically driven mechanical calculator with limited programmability, reading instructions from punched celluloid film.
The IBM Selective Sequence Electronic Calculator (SSEC) was an electromechanical computer built by IBM. Its design was started in late 1944 and it operated from January 1948 to August 1952. It had many of the features of a stored-program computer, and was the first operational machine able to treat its instructions as data, but it was not fully electronic. Although the SSEC proved useful for several high-profile applications, it soon became obsolete. As the last large electromechanical computer ever built, its greatest success was the publicity it provided for IBM.
The Harvard Mark III, also known as ADEC was an early computer that was partially electronic and partially electromechanical. It was built at Harvard University under the supervision of Howard Aiken for use at Naval Surface Warfare Center Dahlgren Division.
The United States Naval Surface Warfare Center Dahlgren Division (NSWCDD), named for Rear Admiral John A. Dahlgren, is located in King George County, Virginia, in close proximity to the largest fleet concentration area in the Navy. NSWCDD is part of the Naval Surface Warfare Centers under the Naval Sea Systems Command (NAVSEA). NSWCDD was initially established 16 October 1918 as a remote extension of Maryland's Indian Head Proving Ground used for testing naval guns. The Dahlgren site was named the Lower Station, Dahlgren Naval Proving Ground when it first opened. The location on the Potomac River was specifically chosen for the development of a long ballistic test range on the Potomac River, required for the testing of modern, high-powered munitions.
An instruction set simulator (ISS) is a simulation model, usually coded in a high-level programming language, which mimics the behavior of a mainframe or microprocessor by "reading" instructions and maintaining internal variables which represent the processor's registers.
A hardware bug is a defect in the design, manufacture, or operation of computer hardware that causes incorrect operation. It is the counterpart of software bugs which refer to flaws in the code which operates computers, and is the original context in which "bug" was used to refer to such flaws. Intermediate between hardware and software are microcode and firmware which may also have such defects. In common usage, a bug is subtly different from a "glitch" which may be more transient than fundamental, and somewhat different from a "quirk" which may be considered useful or intrinsic. Errata may be published by the manufacturer to reflect such unintended operation, and "errata" is sometimes used as a term for the flaws themselves.
A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations (computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These programs enable computers to perform a wide range of tasks. A computer system is a nominally complete computer that includes the hardware, operating system, and peripheral equipment needed and used for full operation. This term may also refer to a group of computers that are linked and function together, such as a computer network or computer cluster.
The Olivetti Programma 101, also known as Perottina or P101, is one of the first "all in one" commercial desktop programmable calculators, although not the first. Produced by Italian manufacturer Olivetti, based in Ivrea, Piedmont, and invented by the Italian engineer Pier Giorgio Perotto, the P101 used many features of large computers of that period. It was launched at the 1964 New York World's Fair; volume production started in 1965. A futuristic design for its time, the Programma 101 was priced at $3,200 (equivalent to $29,700 in 2022). About 44,000 units were sold, primarily in the US.
In computer programming and software development, debugging is the process of finding and resolving bugs within computer programs, software, or systems.
In engineering, a bug is a defect in the design, manufacture or operation of machinery, circuitry, electronics, hardware, or software that produces undesired results or impedes operation. It is contrasted with a glitch which may only be transient. Sometimes what might be seen as unintended or defective operation can be seen as a feature.
Richard Milton Bloch was a pioneering American computer programmer. Bloch, Grace Hopper, and Robert Campbell were the first programmers of the Harvard Mark I, an electromechanical computer which, when it began operation in 1944, was the first American programmable computer.
