floating point

MBASIC was an interpreter. Program source text was stored in memory in tokenized form, with BASIC keywords replaced by one-byte tokens which saved memory space and speeded execution. Programs could be listed on the screen for editing, or saved to disk in either a compressed binary format or as plain ASCII text. Every source line was identified with a number, which could be used as the target of a GOTO transfer. Only on-screen line editing commands were provided - no full-screen cursor-addressing editing was available owing to the limitations of su ...

See also:

MBASIC, MBASIC - Environment, MBASIC - Features, MBASIC - PEEKs POKEs and user functions, MBASIC - Successors to MBASIC, MBASIC - Importance of MBASIC

Read more here: » MBASIC: Encyclopedia II - MBASIC - Features

Many problems in continuous mathematics do not possess a closed-form solution. Examples are finding the integral of exp(−x2) (see error function) and solving a general polynomial equation of degree five or higher (see Abel-Ruffini theorem). In these situations, one has two options left: either one tries to find an approximate solution using asymptotic analysis or one seeks a numerical solution. The latter choice describes the field of numerical analysis. See also:

Numerical analysis, Numerical analysis - General introduction, Numerical analysis - Direct and iterative methods, Numerical analysis - Discretization, Numerical analysis - The generation and propagation of errors, Numerical analysis - Applications, Numerical analysis - Areas of study, Numerical analysis - Computing values of functions, Numerical analysis - Interpolation extrapolation and regression, Numerical analysis - Solving equations and systems of equations, Numerical analysis - Optimization, Numerical analysis - Evaluating integrals, Numerical analysis - Differential equations, Numerical analysis - History, Numerical analysis - Software

Read more here: » Numerical analysis: Encyclopedia II - Numerical analysis - General introduction

The simplest numeral system is the unary numeral system, in which every natural number is represented by a corresponding number of symbols. If the symbol ′ is chosen, for example, then the number seven would be represented by ′′′′′′′. The unary system is normally only useful for small numbers. It has some uses in theoretical computer science. Elias gamma coding is commonly used in da ...

See also:

Numeral system, Numeral system - Types of numeral systems, Numeral system - History, Numeral system - Bases used, Numeral system - Positional systems in detail, Numeral system - Change of radix, Numeral system - Generalized variable-length integers, Numeral system - Reference

Read more here: » Numeral system: Encyclopedia II - Numeral system - Types of numeral systems

The discrete Fourier transform is given by The number-theoretic transform operates on a sequence of n numbers, modulus a prime number p of the form p=ξn+1, where ξ can be any positive integer. The number is replaced by a number ωξ where ω is a "primitive root" of p, a number where the lowest positive integer ж where ωж=1 is ж=p-1. There should be plenty of ω which ...

See also:

Number-theoretic transform, Number-theoretic transform - Definition, Number-theoretic transform - Properties, Number-theoretic transform - Proof of inverse NTT, Number-theoretic transform - External link

Read more here: » Number-theoretic transform: Encyclopedia II - Number-theoretic transform - Definition

Xbox - Development. The Xbox was initially developed within Microsoft by a small team which included Seamus Blackley, a game developer and high energy physicist. The rumors of a video game console being developed by Microsoft first emerged at the end of 1999 following interviews of Bill Gates. Gates said that a gaming/multimedia device was essential for multimedia convergence in the new times of digital entertainment. In May 2000 the "Xbox Project" was of ...

See also:

Xbox, Xbox - History, Xbox - Development, Xbox - Software, Xbox - Xbox Live, Xbox - Market share, Xbox - Hardware, Xbox - Detailed specifications, Xbox - Special Limited Editions, Xbox - Official Xbox accessories, Xbox - Audio/video connectors, Xbox - Networking, Xbox - Multimedia, Xbox - Controllers and removable storage, Xbox - Screenshots, Xbox - Xbox and DirectX, Xbox - Modding the Xbox, Xbox - Price history, Xbox - Xbox 360, Xbox - Programming for Xbox

Read more here: » Xbox: Encyclopedia II - Xbox - History

From 1952 into the late 1960s, IBM manufactured and marketed several large computer models, known as the IBM 700/7000 series. The 700s were based on vacuum tubes, while the later 7000s used transistors. These machines established IBM's dominance in electronic data processing. IBM had two model categories: one (701, 704, 709, 7090, 7040) for engineering and scientific use, and one (702, 705, 7080, 7070, 7010) for commercial or data processing use. IBM initially sold its computers without any software, expecting customers to write their own; a ...

See also:

IBM mainframe, IBM mainframe - History, IBM mainframe - Software, IBM mainframe - Operating systems, IBM mainframe - Middleware, IBM mainframe - Notes

Read more here: » IBM mainframe: Encyclopedia II - IBM mainframe - History

Implicit type conversion, also known as coercion, is an automatic type conversion by the compiler. Some languages allow, or even require compilers to provide coercion. In a mixed type expression, a subtype s will be converted to a supertype t or some subtypes s1, s2, ... will be converted to a supertype t (maybe none of the si is of type t) at runtime so that the program will run correctly. For example: double d; long l; int i; if (d > i) ...

See also:

Type conversion, Type conversion - Aviation, Type conversion - Computing, Type conversion - Implicit type conversion, Type conversion - Explicit type conversion, Type conversion - in Ada, Type conversion - in C/C++, Type conversion - Two common casting styles

Read more here: » Type conversion: Encyclopedia II - Type conversion - Implicit type conversion

The design for the EDVAC was developed before the ENIAC was even operational, it was intended to resolve many of the problems created by the ENIAC's design. Like the ENIAC, the EDVAC was built for the U.S. Army's Ballistics Research Laboratory at the Aberdeen Proving Ground by the University of Pennsylvania. The ENIAC designers Eckert & Mauchly were joined by John von Neumann and some others and the new design was based on von ...

See also:

EDVAC, EDVAC - Project origin and plans, EDVAC - Technical description, EDVAC - Installation and operation

Read more here: » EDVAC: Encyclopedia II - EDVAC - Project origin and plans

The computer’s service revolves directly around the ALU. Fundamentally, the ALU receives the data through input registers that are given data from the memory. This data is processed and the results of this operation are stored into ALU output registers where they wait to be transferred back out to the memory. [3]. There is also a Control Unit that gives signals to the ALU which instruct it on what operations should be performed. This relationship between the Control Unit and the ALU can be compared ...

See also:

Arithmetic logic unit, Arithmetic logic unit - Von Neumann's proposal, Arithmetic logic unit - Practical overview, Arithmetic logic unit - ALU operations, Arithmetic logic unit - Inputs and outputs, Arithmetic logic unit - Notes

Read more here: » Arithmetic logic unit: Encyclopedia II - Arithmetic logic unit - Practical overview

CDC's first products were based on the machines designed at ERA, which Seymour Cray had been asked to update after moving to CDC. After an experimental machine known as the Little Character, they delivered the CDC 1604, one of the first commercial transistor-based computers, and one of the fastest machines on the market. Management was delighted, and made plans for a new series of machines that were more tailored to business use; they would include instructions for character handling and record keeping for instance. Cray was not inter ...

See also:

CDC 6600, CDC 6600 - History and impact, CDC 6600 - Description, CDC 6600 - The Central Processor CP, CDC 6600 - Memory organization, CDC 6600 - Peripheral Processors PPs, CDC 6600 - Wordlengths characters, CDC 6600 - Physical design

Read more here: » CDC 6600: Encyclopedia II - CDC 6600 - History and impact

The Ariane 5 software reused the specifications from the Ariane 4, but the Ariane 5's flight path was considerably different and beyond the range for which the reused code had been designed. Specifically, the Ariane 5's greater acceleration caused the back-up and primary inertial guidance computers to crash, after which the launcher's nozzles were directed by spurious data. Pre-flight tests had never been performed on the re-alignment code under simulated Ariane 5 flight conditions, ...

See also:

Ariane 5 Flight 501, Ariane 5 Flight 501 - Summary, Ariane 5 Flight 501 - Full report, Ariane 5 Flight 501 - Aftermath

Read more here: » Ariane 5 Flight 501: Encyclopedia II - Ariane 5 Flight 501 - Summary

Ariane 5's first test flight (Ariane 5 Flight 501) on 4 June 1996 failed, with the rocket self-destructing 37 seconds after launch because of a malfunction in the control software, which was arguably one of the most expensive computer bugs in history. A data conversion from 64-bit floating point to 16-bit signed integer value had caused a processor trap (operand error). The floating point number had a value too large to be represented by a 16-bit signed integer. Efficiency considerations had led to the disabling of the software handler (in Ada code) for this trap, although other conversions of comparabl ...

See also:

Ariane 5, Ariane 5 - Components, Ariane 5 - Variants, Ariane 5 - Future developments, Ariane 5 - Cancelled developments, Ariane 5 - Launch history, Ariane 5 - Ariane 5 flights, Ariane 5 - Upcoming flight

Read more here: » Ariane 5: Encyclopedia II - Ariane 5 - Launch history

FOCAL15 V6B *01.10 ASK "IN WHAT YEAR WERE YOU BORN?", YEAR *01.20 SET YEAROFFOCAL=YEAR-1969+1 *01.30 IF (YEAROFFOCAL) 02.10,02.10,01.40 *01.40 TYPE "YOU WERE BORN IN THE YEAR ",YEAROFFOCAL," OF FOCAL!",! *01.50 GOTO 01.10 *02.10 TYPE "YOU ARE TOO OLD FOR FOCAL, POPS",! *02.20 GOTO 01.10 *GO IN WHAT YEAR WERE YOU BORN?:1969 YOU WERE BORN IN THE YEAR 1.0000 OF FOCAL! IN WHAT YEAR WERE YOU BORN?:1950 YOU ARE TOO OLD FOR FOCAL, POPS IN WHAT YEAR WERE YOU BORN?: This program tak ...

See also:

FOCAL programming language, FOCAL programming language - Sample Session with Focal on a PDP15, FOCAL programming language - External link

Read more here: » FOCAL programming language: Encyclopedia II - FOCAL programming language - Sample Session with Focal on a PDP15

Suppose you need to find numbers x, y, and z such that the following three equations are all simultaneously true: 2x + y − z = 8, − 3x − y + 2z = − 11, − 2x + y + 2z = − 3 This is called a system of linear equations for the unknowns x, y, and z. They are called linear bec ...

See also:

Gaussian elimination, Gaussian elimination - History, Gaussian elimination - Numerical analysis, Gaussian elimination - Example, Gaussian elimination - Row echelon and reduced row echelon form, Gaussian elimination - Other applications, Gaussian elimination - Finding the inverse of a matrix, Gaussian elimination - The general algorithm to compute ranks and bases

Read more here: » Gaussian elimination: Encyclopedia II - Gaussian elimination - Example

Even before the completion of the Atlas (UNIVAC 1101), the Navy asked Engineering Research Associates to design a more powerful machine. This project became Task 29, and the computer was designated Atlas II. In 1952, Engineering Research Associates asked the Armed Forces Security Agency (the predecessor of the NSA) for approval to sell the Atlas II commercially. Permission was given, on the condition that several specialized instructions would be removed. The commercial version then became the UNIVAC 1103. Because of security classification, Remington Rand management w ...

See also:

UNIVAC 1103, UNIVAC 1103 - History

Read more here: » UNIVAC 1103: Encyclopedia II - UNIVAC 1103 - History

CPU design - 1950s: early designs. Each of the computer designs of the early 1950s was a unique design; there were no upward-compatible machines or computer architectures with multiple, differing implementations. Programs written for one machine would not run on another kind, even other kinds from the same company. This was not a major drawback at the time because there was not a large body of software developed to run on computers, so star ...

See also:

CPU design, CPU design - Goals of CPU design, CPU design - History of general purpose CPUs, CPU design - 1950s: early designs, CPU design - 1960s: the computer revolution and CISC, CPU design - 1970s: large scale integration, CPU design - Early 1980s: the lessons of RISC, CPU design - Mid-1980s to today: exploiting instruction level parallelism, CPU design - 1990 to today: looking forward, CPU design - Embedded design, CPU design - Other design issues, CPU design - Design concepts, CPU design - RISC, CPU design - Instruction pipelining, CPU design - Cache, CPU design - Superscalar designs, CPU design - Out-of-order execution, CPU design - Speculative execution, CPU design - Multiprocessing and Multithreading

Read more here: » CPU design: Encyclopedia II - CPU design - History of general purpose CPUs

CPU design - 1950s: early designs. Each of the computer designs of the early 1950s was a unique design; there were no upward-compatible machines or computer architectures with multiple, differing implementations. Programs written for one machine would not run on another kind, even other kinds from the same company. This was not a major drawback at the time because there was not a large body of software developed to run on computers, so star ...

See also:

CPU design, CPU design - History of general purpose CPUs, CPU design - 1950s: early designs, CPU design - 1960s: the computer revolution and CISC, CPU design - 1970s: large scale integration, CPU design - Early 1980s: the lessons of RISC, CPU design - Mid-1980s to today: exploiting instruction level parallelism, CPU design - 1990 to today: looking forward, CPU design - Embedded design, CPU design - Other design issues, CPU design - Design concepts, CPU design - RISC, CPU design - Instruction pipelining, CPU design - Speculative execution, CPU design - Cache, CPU design - Out-of-order execution, CPU design - Superscalar designs, CPU design - Simultaneous multithreading

Read more here: » CPU design: Encyclopedia II - CPU design - History of general purpose CPUs

There are several scenarios where a context switch needs to occur. Context switch - Multitasking. Most commonly, within some scheduling schema, one process needs to be switched out of the CPU so another process can run. Within a preemptive multitasking operating system, the scheduler allows every task to run for some certain amount of time, called its time slice. However, if a process does not voluntarily yield the CPU (for example, by performing an I/O operation), a timer interrupt fires, an ...

See also:

Context switch, Context switch - When to switch?, Context switch - Multitasking, Context switch - Interrupt handling, Context switch - User and kernel mode switching, Context switch - Context switch: steps, Context switch - Software vs hardware context switching

Read more here: » Context switch: Encyclopedia II - Context switch - When to switch?

Dhrystone's eventual importance as an indicator of general-purpose ("integer") performance of new computers made it a target for commercial compiler writers. Various modern compiler techniques (such as dead code elimination) make the use and design of synthetic benchmarks more difficult. Version 2.0 of the benchmark, released by Weicker and Richardson in March of 1988, had a number of changes intended to foil a range of compiler techniques. Yet it was carefully crafted so as not to change the underlying benchmark. This effort to foil compile ...

See also:

Dhrystone, Dhrystone - Dhrystone vs Whetstone, Dhrystone - Issues addressed by Dhrystone, Dhrystone - Results

Read more here: » Dhrystone: Encyclopedia II - Dhrystone - Issues addressed by Dhrystone

Its early CPU products included the 486SLC and 486DLC, released in 1992, which, despite their names, were pin-compatible with the 386SX and DX, respectively. While they added an on-chip L1 cache and the 486 instruction set, performance-wise they were somewhere between the 386 and the 486. The chips were mostly used as upgrades, either by end users looking to improve performance of an aging 386 and especially by dealers, who by changing the CPU could turn slow-selling 386 boards into budget 486 boards. The chips were widely criticized in prod ...

See also:

Cyrix, Cyrix - Products, Cyrix - PR Rating, Cyrix - Manufacturing partners, Cyrix - Legal troubles, Cyrix - Merger with National Semiconductor, Cyrix - Legacy

Read more here: » Cyrix: Encyclopedia II - Cyrix - Products

Digital signal processing can be done on general-purpose microprocessors. Possible optimizations: Digital signal processor - Data operators. Saturation arithmetic, in which operations that produce overflows will accumulate at the maximum (or minimum) values that the register can hold rather than wrapping around (maximum+1 doesn't equal minimum as in many general-purpose CPUs, instead it stays at maximum). Sometimes various sticky bits operation modes are available. Multiply-accumulate (MAC) ...

See also:

Digital signal processor, Digital signal processor - Real-time processing, Digital signal processor - Digital signal processing, Digital signal processor - Data operators, Digital signal processor - Program flow, Digital signal processor - History

Read more here: » Digital signal processor: Encyclopedia II - Digital signal processor - Digital signal processing

Constant folding is the process of simplifying constant expressions at compile time. Terms in constant expressions are typically simple literals, such as the integer 2, but can also be variables whose values are never modified, or variables explicitly marked as constant. Consider the statement: i = 320 * 200 * 32; Most modern compilers would not actually generate two multiply instructions and a store for this statement. Instead, they identify constructs such as these, and substitute the computed values at compile time (in this case, 2,048,000), ...

See also:

Constant folding, Constant folding - Constant folding, Constant folding - Constant folding and cross compilation, Constant folding - Constant propagation, Constant folding - The optimizations in action

Read more here: » Constant folding: Encyclopedia II - Constant folding - Constant folding