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90-484: Grand Prix Legends is a computer racing simulator developed by Papyrus Design Group and published in 1998 by Sierra On-Line under the Sierra Sports banner. It is inspired by the 1967 Grand Prix season ; teams included are Brabham, BRM, Eagle, Ferrari and Lotus. Two fictional teams called "Murasama" and "Coventry" replaced the other big names. The Japanese team possibly because of copyright claims. Whilst it

180-442: A TV set or an appropriately sized computer display , and is often used as a digital photo viewer, music and video player, TV receiver, and digital video recorder. HTPCs are also referred to as media center systems or media servers . The goal is to combine many or all components of a home theater setup into one box. HTPCs can also connect to services providing on-demand movies and TV shows. HTPCs can be purchased pre-configured with

270-492: A code obfuscation technique as a measure against disassembly and tampering. The principle is also used in shared code sequences of fat binaries which must run on multiple instruction-set-incompatible processor platforms. This property is also used to find unintended instructions called gadgets in existing code repositories and is used in return-oriented programming as alternative to code injection for exploits such as return-to-libc attacks . In some computers,

360-401: A kit form and in limited volumes, and were of interest mostly to hobbyists and technicians. Minimal programming was done with toggle switches to enter instructions, and output was provided by front panel lamps. Practical use required adding peripherals such as keyboards, computer displays , disk drives , and printers . Micral N was the earliest commercial, non-kit microcomputer based on

450-511: A multitasking operating system . Eventually, due to the influence of the IBM PC on the personal computer market , personal computers and home computers lost any technical distinction. Business computers acquired color graphics capability and sound, and home computers and game systems users used the same processors and operating systems as office workers. Mass-market computers had graphics capabilities and memory comparable to dedicated workstations of

540-553: A portable computer prototype called SCAMP (Special Computer APL Machine Portable) based on the IBM PALM processor with a Philips compact cassette drive, small CRT , and full function keyboard. SCAMP emulated an IBM 1130 minicomputer in order to run APL/1130. In 1973, APL was generally available only on mainframe computers, and most desktop sized microcomputers such as the Wang 2200 or HP 9800 offered only BASIC . Because SCAMP

630-469: A touchscreen display, which can be controlled using either a stylus pen or finger. Some tablets may use a hybrid or convertible design, offering a keyboard that can either be removed as an attachment, or a screen that can be rotated and folded directly over top the keyboard. Some tablets may use desktop-PC operating system such as Windows or Linux, or may run an operating system designed primarily for tablets. Many tablet computers have USB ports, to which

720-835: A 4096-color palette, stereo sound, Motorola 68000 CPU, 256 KB RAM, and 880 KB 3.5-inch disk drive, for US$ 1,295. IBM's first PC was introduced on 12 August 1981 setting what became a mass market standard for PC architecture. In 1982 The Computer was named Machine of the Year by Time magazine. Somewhat larger and more expensive systems were aimed at office and small business use. These often featured 80-column text displays but might not have had graphics or sound capabilities. These microprocessor-based systems were still less costly than time-shared mainframes or minicomputers. Workstations were characterized by high-performance processors and graphics displays, with large-capacity local disk storage, networking capability, and running under

810-529: A computer program which is actually read and interpreted by the computer. A program in machine code consists of a sequence of machine instructions (possibly interspersed with data). Each machine code instruction causes the CPU to perform a specific task. Examples of such tasks include: In general, each architecture family (e.g., x86 , ARM ) has its own instruction set architecture (ISA), and hence its own specific machine code language. There are exceptions, such as

900-410: A computer that could fit on a desk was remarkably small, leading to the desktop nomenclature. More recently, the phrase usually indicates a particular style of computer case . Desktop computers come in a variety of styles ranging from large vertical tower cases to small models which can be tucked behind or rest directly beneath (and support) LCD monitors . While the term desktop often refers to

990-557: A computer with a vertically aligned computer tower case , these varieties often rest on the ground or underneath desks. Despite this seeming contradiction, the term desktop does typically refer to these vertical tower cases as well as the horizontally aligned models which are designed to literally rest on top of desks and are therefore more appropriate to the desktop term, although both types qualify for this desktop label in most practical situations aside from certain physical arrangement differences. Both styles of these computer cases hold

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1080-510: A desk, including a keyboard, a small one-line display, and printer. The Wang 2200 microcomputer of 1973 had a full-size cathode ray tube (CRT) and cassette tape storage. These were generally expensive specialized computers sold for business or scientific uses. 1974 saw the introduction of what is considered by many to be the first true personal computer, the Altair 8800 created by Micro Instrumentation and Telemetry Systems (MITS) . Based on

1170-416: A direct map between the numerical machine code and a human-readable mnemonic. In assembly, numerical opcodes and operands are replaced with mnemonics and labels. For example, the x86 architecture has available the 0x90 opcode; it is represented as NOP in the assembly source code . While it is possible to write programs directly in machine code, managing individual bits and calculating numerical addresses

1260-415: A few years before. Even local area networking, originally a way to allow business computers to share expensive mass storage and peripherals, became a standard feature of personal computers used at home. An increasingly important set of uses for personal computers relied on the ability of the computer to communicate with other computer systems, allowing interchange of information. Experimental public access to

1350-432: A graphics card installed. For this reason, desktop computers are usually preferred over laptops for gaming purposes. Unlike desktop computers, only minor internal upgrades (such as memory and hard disk drive) are feasible owing to the limited space and power available. Laptops have the same input and output ports as desktops, for connecting to external displays, mice, cameras, storage devices and keyboards. Laptops are also

1440-470: A hardware specification called Handheld PC was later released by Microsoft that run the Windows CE operating system. Machine code In computer programming , machine code is computer code consisting of machine language instructions , which are used to control a computer's central processing unit (CPU). For conventional binary computers , machine code is the binary representation of

1530-438: A hinged second panel containing a flat display screen. Closing the laptop protects the screen and keyboard during transportation. Laptops generally have a rechargeable battery , enhancing their portability. To save power, weight and space, laptop graphics chips are in many cases integrated into the CPU or chipset and use system RAM, resulting in reduced graphics performance when compared to desktop machines, that more typically have

1620-408: A keyboard or mouse can be connected. Smartphones are often similar to tablet computers , the difference being that smartphones always have cellular integration. They are generally smaller than tablets, and may not have a slate form factor. The ultra-mobile PC (UMPC) is a small tablet computer . It was developed by Microsoft , Intel and Samsung , among others. Current UMPCs typically feature

1710-540: A larger screen or use with video projectors. IBM PC-compatible suitcase format computers became available soon after the introduction of the PC, with the Compaq Portable being a leading example of the type. Later models included a hard drive to give roughly equivalent performance to contemporary desktop computers. The development of thin plasma display and LCD screens permitted a somewhat smaller form factor, called

1800-465: A little more expensive compared to desktops, as the miniaturized components for laptops themselves are expensive. Notebook computers such as the TRS-80 Model 100 and Epson HX-20 had roughly the plan dimensions of a sheet of typing paper ( ANSI A or ISO A4 ). These machines had a keyboard with slightly reduced dimensions compared to a desktop system, and a fixed LCD display screen coplanar with

1890-486: A machine with a single accumulator , the accumulator is implicitly both the left operand and result of most arithmetic instructions. Some other architectures, such as the x86 architecture, have accumulator versions of common instructions, with the accumulator regarded as one of the general registers by longer instructions. A stack machine has most or all of its operands on an implicit stack. Special purpose instructions also often lack explicit operands; for example, CPUID in

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1980-432: A manufacturer-supported channel, and end-user program development may be discouraged by lack of support by the manufacturer. Since the early 1990s, Microsoft operating systems (first with MS-DOS and then with Windows ) and Intel hardware – collectively called Wintel – have dominated the personal computer market, and today the term PC normally refers to the ubiquitous Wintel platform. Alternatives to Windows occupy

2070-739: A microprocessor, the Intel 8008 . It was built starting in 1972, and a few hundred units were sold. This had been preceded by the Datapoint 2200 in 1970, for which the Intel 8008 had been commissioned, though not accepted for use. The CPU design implemented in the Datapoint 2200 became the basis for x86 architecture used in the original IBM PC and its descendants. In 1973, the IBM Los Gatos Scientific Center developed

2160-621: A minority share of the market; these include the Mac platform from Apple (running the macOS operating system), and free and open-source , Unix-like operating systems, such as Linux . Other notable platforms until the 1990s were the Amiga from Commodore , and the PC-98 from NEC . The term PC is an initialism for personal computer. While the IBM Personal Computer incorporated

2250-481: A new naming scheme: devices without an integrated phone are called Windows Mobile Classic instead of Pocket PC, while devices with an integrated phone and a touch screen are called Windows Mobile Professional. Palmtop PCs were miniature pocket-sized computers running DOS that first came about in the late 1980s, typically in a clamshell form factor with a keyboard. Non-x86 based devices were often called palmtop computers, examples being Psion Series 3 . In later years

2340-433: A one-to-one mapping to machine code. The assembly language decoding method is called disassembly . Machine code may be decoded back to its corresponding high-level language under two conditions: The first condition is to accept an obfuscated reading of the source code. An obfuscated version of source code is displayed if the machine code is sent to a decompiler of the source language. The second condition requires

2430-400: A paging based system, if the current page actually holds machine code by an execute bit — pages have multiple such permission bits (readable, writable, etc.) for various housekeeping functionality. E.g. on Unix-like systems memory pages can be toggled to be executable with the mprotect() system call, and on Windows, VirtualProtect() can be used to achieve a similar result. If an attempt

2520-406: A preview of features that would later become staples of personal computers: e-mail , hypertext , word processing , video conferencing , and the mouse . The demonstration required technical support staff and a mainframe time-sharing computer that were far too costly for individual business use at the time. Early personal computers‍—‌generally called microcomputers‍—‌were often sold in

2610-615: A shared mainframe computer system was demonstrated as early as 1973 in the Community Memory project, but bulletin board systems and online service providers became more commonly available after 1978. Commercial Internet service providers emerged in the late 1980s, giving public access to the rapidly growing network. In 1991, the World Wide Web was made available for public use. The combination of powerful personal computers with high-resolution graphics and sound, with

2700-444: A tag and a Y field. In addition to transfer (branch) instructions, these machines have skip instruction that conditionally skip one or two words, e.g., Compare Accumulator with Storage (CAS) does a three way compare and conditionally skips to NSI, NSI+1 or NSI+2, depending on the result. The MIPS architecture provides a specific example for a machine code whose instructions are always 32 bits long. The general type of instruction

2790-655: A television already in the home as the computer display, with low-detail blocky graphics and a limited color range, and text about 40 characters wide by 25 characters tall. Sinclair Research , a UK company, produced the ZX Series‍—;‌the ZX80 (1980), ZX81 (1981), and the ZX Spectrum ; the latter was introduced in 1982, and totaled 8 million unit sold. Following came the Commodore 64 , totaled 17 million units sold,

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2880-406: A time, they are commonly connected to a local area network and run multi-user operating systems . Workstations are used for tasks such as computer-aided design , drafting and modeling, computation-intensive scientific and engineering calculations, image processing, architectural modeling, and computer graphics for animation and motion picture visual effects. Before the widespread use of PCs,

2970-601: A wide range of users, not just experienced electronics hobbyists who had the soldering skills to assemble a computer kit. The Apple I as delivered was still technically a kit computer, as it did not have a power supply, case, or keyboard when it was delivered to the Byte Shop. The first successfully mass-marketed personal computer to be announced was the Commodore PET after being revealed in January 1977. However, it

3060-542: Is a desktop computer that generally comprises a high-performance video card , processor and RAM, to improve the speed and responsiveness of demanding video games . An all-in-one computer (also known as single-unit PCs) is a desktop computer that combines the monitor and processor within a single unit. A separate keyboard and mouse are standard input devices, with some monitors including touchscreen capability. The processor and other working components are typically reduced in size relative to standard desktops, located behind

3150-495: Is a portable computer that provides the full capabilities of a desktop computer . Such computers are currently large laptops. This class of computers usually includes more powerful components and a larger display than generally found in smaller portable computers, and may have limited battery capacity or no battery. Netbooks , also called mini notebooks or subnotebooks , were a subgroup of laptops suited for general computing tasks and accessing web-based applications . Initially,

3240-477: Is generally different from bytecode (also known as p-code), which is either executed by an interpreter or itself compiled into machine code for faster (direct) execution. An exception is when a processor is designed to use a particular bytecode directly as its machine code, such as is the case with Java processors . Machine code and assembly code are sometimes called native code when referring to platform-dependent parts of language features or libraries. From

3330-449: Is given by the op (operation) field, the highest 6 bits. J-type (jump) and I-type (immediate) instructions are fully specified by op . R-type (register) instructions include an additional field funct to determine the exact operation. The fields used in these types are: rs , rt , and rd indicate register operands; shamt gives a shift amount; and the address or immediate fields contain an operand directly. For example, adding

3420-428: Is made to execute machine code on a non-executable page, an architecture specific fault will typically occur. Treating data as machine code , or finding new ways to use existing machine code, by various techniques, is the basis of some security vulnerabilities. Similarly, in a segment based system, segment descriptors can indicate whether a segment can contain executable code and in what rings that code can run. From

3510-429: Is provided in ready-to-run , or binary form. Software for personal computers is typically developed and distributed independently from the hardware or operating system manufacturers. Many personal computer users no longer need to write their programs to make any use of a personal computer, although end-user programming is still feasible. This contrasts with mobile systems, where software is often available only through

3600-425: Is rarely a problem. Systems may also differ in other details, such as memory arrangement, operating systems, or peripheral devices . Because a program normally relies on such factors, different systems will typically not run the same machine code, even when the same type of processor is used. A processor's instruction set may have fixed-length or variable-length instructions. How the patterns are organized varies with

3690-475: Is rumoured the other fictional team was included due to a misunderstanding. The game offers several modes in which the player can race alone or against AI opponents. The game also features multiplayer via LAN . Many parameters affecting the skill and aggressiveness of the AI drivers can be specified. The game was in development for three years with a team of 25 to 30 people. Inspired by the 1966 film Grand Prix ,

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3780-512: Is tedious and error-prone. Therefore, programs are rarely written directly in machine code. However, an existing machine code program may be edited if the assembly source code is not available. The majority of programs today are written in a high-level language . A high-level program may be translated into machine code by a compiler . Every processor or processor family has its own instruction set . Instructions are patterns of bits , digits, or characters that correspond to machine commands. Thus,

3870-419: Is typically set to a hard coded value when the CPU is first powered on, and will hence execute whatever machine code happens to be at this address. Similarly, the program counter can be set to execute whatever machine code is at some arbitrary address, even if this is not valid machine code. This will typically trigger an architecture specific protection fault. The CPU is oftentimes told, by page permissions in

3960-536: The Apple I computer circuit board, which was fully prepared and contained about 30 chips. The Apple I computer differed from the other kit-style hobby computers of era. At the request of Paul Terrell , owner of the Byte Shop , Jobs and Wozniak were given their first purchase order, for 50 Apple I computers, only if the computers were assembled and tested and not a kit computer. Terrell wanted to have computers to sell to

4050-590: The Bendix G15 and LGP-30 of 1956, and the Soviet MIR series of computers developed from 1965 to 1969. By the early 1970s, people in academic or research institutions had the opportunity for single-person use of a computer system in interactive mode for extended durations, although these systems would still have been too expensive to be owned by a single person. The personal computer was made possible by major advances in semiconductor technology. In 1959,

4140-656: The Galaksija (1983) introduced in Yugoslavia and the Amstrad CPC series (464–6128). In the same year, the NEC PC-98 was introduced, which was a very popular personal computer that sold in more than 18 million units. Another famous personal computer, the revolutionary Amiga 1000 , was unveiled by Commodore on 23 July 1985. The Amiga 1000 featured a multitasking, windowing operating system, color graphics with

4230-539: The Kruskal count , sometimes possible through opcode-level programming to deliberately arrange the resulting code so that two code paths share a common fragment of opcode sequences. These are called overlapping instructions , overlapping opcodes , overlapping code , overlapped code , instruction scission , or jump into the middle of an instruction . In the 1970s and 1980s, overlapping instructions were sometimes used to preserve memory space. One example were in

4320-698: The VAX architecture, which includes optional support of the PDP-11 instruction set; the IA-64 architecture, which includes optional support of the IA-32 instruction set; and the PowerPC 615 microprocessor, which can natively process both PowerPC and x86 instruction sets. Machine code is a strictly numerical language, and it is the lowest-level interface to the CPU intended for a programmer. Assembly language  provides

4410-599: The Zilog Z80 processor, the machine code 00000101 , which causes the CPU to decrement the B general-purpose register , would be represented in assembly language as DEC B . The IBM 704, 709, 704x and 709x store one instruction in each instruction word; IBM numbers the bit from the left as S, 1, ..., 35. Most instructions have one of two formats: For all but the IBM 7094 and 7094 II, there are three index registers designated A, B and C; indexing with multiple 1 bits in

4500-405: The lunchbox computer. The screen formed one side of the enclosure, with a detachable keyboard and one or two half-height floppy disk drives, mounted facing the ends of the computer. Some variations included a battery, allowing operation away from AC outlets. A laptop computer is designed for portability with clamshell design, where the keyboard and computer components are on one panel, with

4590-420: The review aggregation website GameRankings . GameSpot said that Grand Prix Legends has the most intense racing experience ever seen on a personal computer. Next Generation highly praised the graphics, gameplay, the recreation of 1967 Grand Prix season (in addition to its cars and tracks of its era), artificial intelligence and realistic driving model physics. The magazine ranked it at #47 in its list of

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4680-460: The silicon integrated circuit (IC) chip was developed by Robert Noyce at Fairchild Semiconductor , and the metal–oxide–semiconductor (MOS) transistor was developed by Mohamed Atalla and Dawon Kahng at Bell Labs . The MOS integrated circuit was commercialized by RCA in 1964, and then the silicon-gate MOS integrated circuit was developed by Federico Faggin at Fairchild in 1968. Faggin later used silicon-gate MOS technology to develop

4770-661: The "1977 trinity". Mass-market, ready-assembled computers had arrived, and allowed a wider range of people to use computers, focusing more on software applications and less on development of the processor hardware. In 1977 the Heath company introduced personal computer kits known as Heathkits , starting with the Heathkit H8 , followed by the Heathkit H89 in late 1979. With the purchase of the Heathkit H8 you would obtain

4860-436: The "combination of treacherous gameplay, sometimes glacial frame rates, and esoteric subject matter". It ultimately totaled 200,000 sales by 2004. The game was the runner-up for Computer Gaming World ' s 1998 "Best Driving" award, and for GameSpot ' s 1998 "Driving Game of the Year" award, both of which ultimately went to Need for Speed III: Hot Pursuit . The staff of the former commented that Grand Prix Legends

4950-403: The 1967 Grand Prix season meant that some of the tracks the designers wanted to recreate no longer existed in their original form. The team visited town halls to get blueprints for defunct tracks. Papyrus co-founder Dave Kaemmer commented that the licensing for the game was difficult, but they had people who helped them during the development. The game received "favorable" reviews according to

5040-555: The 8-bit Intel 8080 Microprocessor, the Altair is widely recognized as the spark that ignited the microcomputer revolution as the first commercially successful personal computer. The computer bus designed for the Altair was to become a de facto standard in the form of the S-100 bus , and the first programming language for the machine was Microsoft's founding product, Altair BASIC . In 1976, Steve Jobs and Steve Wozniak sold

5130-668: The Fifty Best Games of All Time. The game was a commercial failure; Andy Mahood of PC Gamer US described its sales as "abysmally poor". In 2003, writer Mark H. Walker reported that "the game sold only a few thousand copies" in the United States, which he attributed to the general unpopularity of Formula One racing in the country. He noted that its "steep learning curve kept many fans away" in European markets. GameSpot ' s Gord Goble attributed its performance to

5220-549: The Windows XP, Windows Vista, Windows 7, or Linux operating system , and low-voltage Intel Atom or VIA C7-M processors. A pocket PC is a hardware specification for a handheld-sized computer ( personal digital assistant , PDA) that runs the Microsoft Windows Mobile operating system . It may have the capability to run an alternative operating system like NetBSD or Linux . Pocket PCs have many of

5310-473: The ability to be programmed in both APL and BASIC for engineers, analysts, statisticians, and other business problem-solvers. In the late 1960s such a machine would have been nearly as large as two desks and would have weighed about half a ton. Another desktop portable APL machine, the MCM/70 , was demonstrated in 1973 and shipped in 1974. It used the Intel 8008 processor. A seminal step in personal computing

5400-477: The capabilities of desktop PCs . Numerous applications are available for handhelds adhering to the Microsoft Pocket PC specification, many of which are freeware . Microsoft-compliant Pocket PCs can also be used with many other add-ons like GPS receivers , barcode readers, RFID readers and cameras. In 2007, with the release of Windows Mobile 6, Microsoft dropped the name Pocket PC in favor of

5490-577: The chassis and CPU card to assemble yourself, additional hardware such as the H8-1 memory board that contained 4k of RAM could also be purchased in order to run software. The Heathkit H11 model was released in 1978 and was one of the first 16-bit personal computers; however, due to its high retail cost of $ 1,295 was discontinued in 1982. During the early 1980s, home computers were further developed for household use, with software for personal productivity, programming and games. They typically could be used with

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5580-673: The common people] and help with our income-tax and book-keeping calculations. But this is speculation and there is no sign of it so far. In the history of computing , early experimental machines could be operated by a single attendant. For example, ENIAC which became operational in 1946 could be run by a single, albeit highly trained, person. This mode pre-dated the batch programming, or time-sharing modes with multiple users connected through terminals to mainframe computers. Computers intended for laboratory, instrumentation, or engineering purposes were built, and could be operated by one person in an interactive fashion. Examples include such systems as

5670-511: The designation into its model name, the term originally described personal computers of any brand. In some contexts, PC is used to contrast with Mac, an Apple Macintosh computer. Since none of these Apple products were mainframes or time-sharing systems, they were all personal computers but not PC (brand) computers. In 1995, a CBS segment on the growing popularity of PC reported: "For many newcomers PC stands for Pain and Confusion." The "brain" [computer] may one day come down to our level [of

5760-428: The developers chose to base the game on the 1967 Formula 1 Grand Prix season because during that period tracks were narrow and lined with trees, houses, and other elements that in a video game can serve as backgrounds to enhance the sensation of speed. In addition, the more primitive suspension of cars of the time meant that the car physics could be more visually dramatic. However, the amount of time that has passed since

5850-479: The first single-chip microprocessor , the Intel 4004 , in 1971. The first microcomputers , based on microprocessors, were developed during the early 1970s. Widespread commercial availability of microprocessors, from the mid-1970s onwards, made computers cheap enough for small businesses and individuals to own. In what was later to be called the Mother of All Demos , SRI researcher Douglas Engelbart in 1968 gave

5940-469: The implementation of error tables in Microsoft 's Altair BASIC , where interleaved instructions mutually shared their instruction bytes. The technique is rarely used today, but might still be necessary to resort to in areas where extreme optimization for size is necessary on byte-level such as in the implementation of boot loaders which have to fit into boot sectors . It is also sometimes used as

6030-556: The infrastructure provided by the Internet, and the standardization of access methods of the Web browsers , established the foundation for a significant fraction of modern life, from bus time tables through unlimited distribution of free videos through to online user-edited encyclopedias. A workstation is a high-end personal computer designed for technical, mathematical, or scientific applications. Intended primarily to be used by one person at

6120-511: The instruction set is specific to a class of processors using (mostly) the same architecture . Successor or derivative processor designs often include instructions of a predecessor and may add new additional instructions. Occasionally, a successor design will discontinue or alter the meaning of some instruction code (typically because it is needed for new purposes), affecting code compatibility to some extent; even compatible processors may show slightly different behavior for some instructions, but this

6210-519: The introduction of the IBM PC, portable computers consisting of a processor, display, disk drives and keyboard, in a suit-case style portable housing, allowed users to bring a computer home from the office or to take notes at a classroom. Examples include the Osborne 1 and Kaypro ; and the Commodore SX-64 . These machines were AC-powered and included a small CRT display screen. The form factor

6300-549: The keyboard. These displays were usually small, with 8 to 16 lines of text, sometimes only 40 columns line length. However, these machines could operate for extended times on disposable or rechargeable batteries. Although they did not usually include internal disk drives, this form factor often included a modem for telephone communication and often had provisions for external cassette or disk storage. Later, clamshell format laptop computers with similar small plan dimensions were also called notebooks . A desktop replacement computer

6390-526: The machine code of the architecture is implemented by an even more fundamental underlying layer called microcode , providing a common machine language interface across a line or family of different models of computer with widely different underlying dataflows . This is done to facilitate porting of machine language programs between different models. An example of this use is the IBM System/360 family of computers and their successors. Machine code

6480-455: The monitor, and configured similarly to laptops. A nettop computer was introduced by Intel in February 2008, characterized by low cost and lean functionality. These were intended to be used with an Internet connection to run Web browsers and Internet applications. A Home theater PC (HTPC) combines the functions of a personal computer and a digital video recorder . It is connected to

6570-412: The other four index registers. The effective address is normally Y-C(T), where C(T) is either 0 for a tag of 0, the logical or of the selected index regisrs in multiple tag mode or the selected index register if not in multiple tag mode. However, the effective address for index register control instructions is just Y. A flag with both bits 1 selects indirect addressing; the indirect address word has both

6660-529: The particular architecture and type of instruction. Most instructions have one or more opcode fields that specify the basic instruction type (such as arithmetic, logical, jump , etc.), the operation (such as add or compare), and other fields that may give the type of the operand (s), the addressing mode (s), the addressing offset(s) or index, or the operand value itself (such constant operands contained in an instruction are called immediate ). Not all machines or individual instructions have explicit operands. On

6750-657: The point of view of a process , the code space is the part of its address space where the code in execution is stored. In multitasking systems this comprises the program's code segment and usually shared libraries . In multi-threading environment, different threads of one process share code space along with data space, which reduces the overhead of context switching considerably as compared to process switching. Various tools and methods exist to decode machine code back to its corresponding source code . Machine code can easily be decoded back to its corresponding assembly language source code because assembly language forms

6840-504: The point of view of the CPU, machine code is stored in RAM, but is typically also kept in a set of caches for performance reasons. There may be different caches for instructions and data, depending on the architecture. The CPU knows what machine code to execute, based on its internal program counter. The program counter points to a memory address and is changed based on special instructions which may cause programmatic branches. The program counter

6930-503: The primary defining characteristic of netbooks was the lack of an optical disc drive, smaller size, and lower performance than full-size laptops. By mid-2009 netbooks had been offered to users "free of charge", with an extended service contract purchase of a cellular data plan. Ultrabooks and Chromebooks have since filled the gap left by Netbooks. Unlike the generic Netbook name, Ultrabook and Chromebook are technically both specifications by Intel and Google respectively. A tablet uses

7020-412: The registers 1 and 2 and placing the result in register 6 is encoded: Load a value into register 8, taken from the memory cell 68 cells after the location listed in register 3: Jumping to the address 1024: On processor architectures with variable-length instruction sets (such as Intel 's x86 processor family) it is, within the limits of the control-flow resynchronizing phenomenon known as

7110-498: The required hardware and software needed to add television programming to the PC, or can be assembled from components. Keyboard computers are computers inside of keyboards, generally still designed to be connected to an external computer monitor or television . Examples include the Atari ST , Amstrad CPC , BBC Micro , Commodore 64 , MSX , Raspberry Pi 400 , and the ZX Spectrum . The potential utility of portable computers

7200-416: The result of a constant expression freed up by replacing it by that constant) and other code enhancements. A much more human-friendly rendition of machine language, named assembly language , uses mnemonic codes to refer to machine code instructions, rather than using the instructions' numeric values directly, and uses symbolic names to refer to storage locations and sometimes registers . For example, on

7290-418: The systems hardware components such as the motherboard , processor chip and other internal operating parts. Desktop computers have an external monitor with a display screen and an external keyboard, which are plugged into ports on the back of the computer case. Desktop computers are popular for home and business computing applications as they leave space on the desk for multiple monitors . A gaming computer

7380-443: The tag subtracts the logical or of the selected index registers and loading with multiple 1 bits in the tag loads all of the selected index registers. The 7094 and 7094 II have seven index registers, but when they are powered on they are in multiple tag mode , in which they use only the three of the index registers in a fashion compatible with earlier machines, and require a Leave Multiple Tag Mode ( LMTM ) instruction in order to access

7470-406: The x86 architecture writes values into four implicit destination registers. This distinction between explicit and implicit operands is important in code generators, especially in the register allocation and live range tracking parts. A good code optimizer can track implicit and explicit operands which may allow more frequent constant propagation , constant folding of registers (a register assigned

7560-412: The years in earlier versions: Personal computer Institutional or corporate computer owners in the 1960s had to write their own programs to do any useful work with computers. While personal computer users may develop their applications, usually these systems run commercial software , free-of-charge software (" freeware "), which is most often proprietary, or free and open-source software , which

7650-460: Was apparent early on. Alan Kay described the Dynabook in 1972, but no hardware was developed. The Xerox NoteTaker was produced in a very small experimental batch around 1978. In 1975, the IBM 5100 could be fit into a transport case, making it a portable computer, but it weighed about 50 pounds. Such early portable computers were termed luggables by journalists owing to their heft. Before

7740-705: Was back-ordered and not available until later that year. Three months later (April), the Apple II (usually referred to as the Apple) was announced with the first units being shipped 10 June 1977, and the TRS-80 from Tandy Corporation / Tandy Radio Shack following in August 1977, which sold over 100,000 units during its lifetime. Together, especially in the North American market, these 3 machines were referred to as

7830-401: Was intended to allow these systems to be taken on board an airplane as carry-on baggage, though their high power demand meant that they could not be used in flight. The integrated CRT display made for a relatively heavy package, but these machines were more portable than their contemporary desktop equals. Some models had standard or optional connections to drive an external video monitor, allowing

7920-453: Was the 1973 Xerox Alto , developed at Xerox 's Palo Alto Research Center (PARC) . It had a graphical user interface ( GUI ) which later served as inspiration for Apple's Macintosh , and Microsoft's Windows operating system. The Alto was a demonstration project, not commercialized, as the parts were too expensive to be affordable. Also in 1973 Hewlett Packard introduced fully BASIC programmable microcomputers that fit entirely on top of

8010-500: Was the first to emulate APL/1130 performance on a portable, single user computer, PC Magazine in 1983 designated SCAMP a "revolutionary concept" and "the world's first personal computer". This seminal, single user portable computer now resides in the Smithsonian Institution , Washington, D.C.. Successful demonstrations of the 1973 SCAMP prototype led to the IBM 5100 portable microcomputer launched in 1975 with

8100-528: Was the most ambitious and realistic driving simulation game of 1998, and the toughest to play. The game won Computer Games Strategy Plus ' 1998 "Sports Game of the Year" award. The staff wrote that a few racing games could come close to Grand Prix Racing ' s level of sophistication and uncompromising detail. It also won the Best Racing Game award at the 1998 CNET Gamecenter Awards. Some errors in physics or graphics were found during

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