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94-587: The Power Mac G5 is a series of personal computers designed, manufactured, and sold by Apple Computer, Inc. from 2003 to 2006 as part of the Power Mac series. When introduced, it was the most powerful computer in Apple's Macintosh lineup, and was marketed by the company as the world's first 64-bit desktop computer. It was also the first desktop computer from Apple to use an anodized aluminum alloy enclosure, and one of only three computers in Apple's lineup to utilize

188-442: 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

282-401: 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

376-507: 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

470-544: 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

564-469: 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

658-696: A 36-bit physical memory address to address a maximum of 2 bytes (64 gigabytes) of physical memory , while the PowerPC 970 processor is capable of addressing 2 bytes (4 terabytes ) of physical memory and 2 bytes (16 exabytes ) of virtual memory . Due to its 64-bit processor (and 42-bit MMU ), the final revision of the Power Mac G5 can hold 16 GB of Dual-Channel DDR2 PC4200 RAM using eight memory slots, with support for ECC memory. According to Apple, all of these models are obsolete. Early versions of dual processor G5 computers have noise problems. The first one

752-831: 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

846-410: 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

940-557: 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

1034-401: A core if the processor is a multi-core processor ), but an execution resource within a single CPU such as an arithmetic logic unit . While a superscalar CPU is typically also pipelined , superscalar and pipelining execution are considered different performance enhancement techniques. The former (superscalar) executes multiple instructions in parallel by using multiple execution units, whereas

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1128-506: 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

1222-415: 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

1316-658: A given CPU): Seymour Cray 's CDC 6600 from 1964 is often mentioned as the first superscalar design. The 1967 IBM System/360 Model 91 was another superscalar mainframe. The Intel i960 CA (1989), the AMD 29000 -series 29050 (1990), and the Motorola MC88110 (1991), microprocessors were the first commercial single-chip superscalar microprocessors. RISC microprocessors like these were the first to have superscalar execution, because RISC architectures free transistors and die area which can be used to include multiple execution units and

1410-432: 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

1504-476: A hardware specification called Handheld PC was later released by Microsoft that run the Windows CE operating system. Superscalar A superscalar processor (or multiple-issue processor ) is a CPU that implements a form of parallelism called instruction-level parallelism within a single processor. In contrast to a scalar processor , which can execute at most one single instruction per clock cycle,

1598-484: 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

1692-408: 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

1786-745: A laptop version of the G5 processor. The processor that would run the personal computers was P.A. Semi's preliminarily proposed processor, PWRficient 1682M (PA6T-1682M). The version that would be sampled for pre-production at third quarter of 2006 was a 2 GHz, dual-core CPU with two DDR2 memory controllers, 2 MB of L2 cache, and support for 8 PCI Express lanes. The sampled chip also has lower heat intensity than Intel's Core Duo , which gives off 9–31 W under normal load. According to The Register article, P.A. Semi executives believed that they were all but assured of winning Apple's contract, and CEO Dan Dobberpuhl thought that Apple's hints of moving to Intel were just

1880-530: 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

1974-459: 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

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2068-432: 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

2162-708: 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

2256-601: 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

2350-481: 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

2444-409: A persuading tactic. At the time, the companies were working for PWRficient software. Despite the advantages of more compatible architecture, Apple moved to the Intel architecture officially for 'performance-per-watt' reasons. However, P.A. Semi would not be able to ship its low-power multicore product in volume until 2007, which, combined with P.A. Semi's status as a start-up company, seems to have been

2538-406: 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

2632-600: 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

2726-436: A superscalar CPU the dispatcher reads instructions from memory and decides which ones can be run in parallel, dispatching each to one of the several execution units contained inside a single CPU. Therefore, a superscalar processor can be envisioned as having multiple parallel pipelines, each of which is processing instructions simultaneously from a single instruction thread. Most modern superscalar CPUs also have logic to reorder

2820-399: A superscalar processor can execute more than one instruction during a clock cycle by simultaneously dispatching multiple instructions to different execution units on the processor. It therefore allows more throughput (the number of instructions that can be executed in a unit of time) than would otherwise be possible at a given clock rate . Each execution unit is not a separate processor (or

2914-640: 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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3008-406: 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,

3102-584: 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

3196-498: Is ground loop -based interference, which sometimes causes noise leaks into the analog audio outputs. This bug was fixed in Rev. B G5. The second noise problem came from the 'chirping' sound, which can be triggered by fluctuations in power draw. For example, using Exposé causes a brief chirp. A widely circulated work-around is to disable the CPUs' "nap" feature using Apple's CHUD Tools , but this

3290-542: 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

3384-495: 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,

3478-570: Is for Apple and IBM to come together so that Apple customers get the best of both worlds, the tremendous creativity from the Apple corporation and the tremendous technology from the IBM corporation. IBM invested over US$ 3 billion in a new lab to produce these large, 300 mm wafers." This completely automated facility in East Fishkill, New York figured heavily in IBM's larger microelectronics strategy. The original PowerPC 970 had 50 million transistors and

3572-426: Is no assurance otherwise and failure to detect a dependency would produce incorrect results. No matter how advanced the semiconductor process or how fast the switching speed, this places a practical limit on how many instructions can be simultaneously dispatched. While process advances will allow ever greater numbers of execution units (e.g. ALUs), the burden of checking instruction dependencies grows rapidly, as does

3666-429: 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

3760-454: Is removed and delegated to the compiler . Explicitly parallel instruction computing (EPIC) is like VLIW with extra cache prefetching instructions. Simultaneous multithreading (SMT) is a technique for improving the overall efficiency of superscalar processors. SMT permits multiple independent threads of execution to better utilize the resources provided by modern processor architectures. The fact that they are independent means that we know that

3854-480: Is the difference between scalar and vector arithmetic. A superscalar processor is a mixture of the two. Each instruction processes one data item, but there are multiple execution units within each CPU thus multiple instructions can be processing separate data items concurrently. Superscalar CPU design emphasizes improving the instruction dispatcher accuracy and allowing it to keep the multiple execution units in use at all times. This has become increasingly important as

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3948-641: The ALU , integer multiplier , integer shifter, FPU , etc. There may be multiple versions of each execution unit to enable the execution of many instructions in parallel. This differs from a multi-core processor that concurrently processes instructions from multiple threads, one thread per processing unit (called "core"). It also differs from a pipelined processor , where the multiple instructions can concurrently be in various stages of execution, assembly-line fashion. The various alternative techniques are not mutually exclusive—they can be (and frequently are) combined in

4042-477: The AmigaOne X1000 personal computer. 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

4136-527: 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

4230-578: 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,

4324-634: 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

4418-619: The PowerPC 970 CPU, the others being the iMac G5 and the Xserve G5 . Three generations of Power Mac G5 were released before it was discontinued as part of the Mac transition to Intel processors , making way for its replacement, the Mac Pro . The Mac Pro retained a variation of the G5's enclosure design for seven more years, making it among the longest-lived designs in Apple's history. Officially launched as part of Steve Jobs ' keynote presentation at

4512-588: The Worldwide Developers Conference in June 2003, the Power Mac G5 was introduced with three models, sharing the same physical case, but differing in features and performance. Although somewhat larger than the G4 tower it replaced, the necessity for a complex cooling system meant that the G5 tower had room inside for only one optical drive and two hard drives. Steve Jobs stated during his keynote presentation that

4606-405: 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

4700-460: 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

4794-639: 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

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4888-422: The 2.5 GHz quad-processor model had a liquid cooling system that consisted of a radiator, coolant pump, and heat exchangers bolted to the processors. The cooling system was made by Delphi Automotive , a former Harrison Radiator Division of General Motors . This was a bold step for Apple, and should have allowed the use of very fast processors, giving Apple an advantage in both performance and reliability, but

4982-547: 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

5076-592: The Power Mac G5 would reach 3 GHz "within 12 months." This would never come to pass; after three years, the G5 only reached 2.7 GHz before it was replaced by the Intel Xeon -based Mac Pro , which debuted with processors running at speeds of up to 3 GHz. During the presentation, Apple also showed Virginia Tech 's Mac OS X computer cluster supercomputer (a.k.a. supercluster) known as System X , consisting of 1,100 Power Mac G5 towers operating as processing nodes. The supercomputer managed to become one of

5170-512: The RAM slots. Eventually, this can cause the computer to no longer detect the RAM, and refuse to boot. Fixes for this include having the plate re-soldered, or exposing the other side of the Logic Board to heat from a heat gun. The latter option is far easier, since it requires neither soldering nor the removal of the Logic Board from the computer. All 2.5 GHz and 2.7 GHz dual processor models and

5264-533: 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

5358-469: 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

5452-468: 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

5546-573: 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

5640-673: 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

5734-402: The complexity of register renaming circuitry to mitigate some dependencies. Collectively the power consumption , complexity and gate delay costs limit the achievable superscalar speedup. However even given infinitely fast dependency checking logic on an otherwise conventional superscalar CPU, if the instruction stream itself has many dependencies, this would also limit the possible speedup. Thus

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5828-419: The degree of intrinsic parallelism in the code stream forms a second limitation. Collectively, these limits drive investigation into alternative architectural changes such as very long instruction word (VLIW), explicitly parallel instruction computing (EPIC), simultaneous multithreading (SMT), and multi-core computing . With VLIW, the burdensome task of dependency checking by hardware logic at run time

5922-511: 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

6016-443: The dual-core PowerPC 970MP processors as either the "G5 Dual" (for single-socket, dual-core configurations), or Power Mac G5 Quad (for dual-socket , four-core configurations). The Power Mac G5 line in 2006 consisted of three, dual-core PowerPC G5 configurations, which can communicate through its HyperTransport at half its internal clock speed. Each processor in the Power Mac G5 has two unidirectional 32-bit pathways: one leading to

6110-751: The final blow to the development of Power Mac computers. However, it was also speculated that Apple switched to Intel processor because Apple could no longer abide the constant delays in performance ramp up, desired native Windows compatibility, or it was Apple's strategy to shift its business focus away from desktop computing to iPod (and subsequently iOS ) development. Apple acquired P.A. Semi in 2008, using P.A. Semi's engineering resources to develop ARM CPUs for their iPhone , iPod Touch , iPad , and Apple TV product lines; and would go on to eventually come full circle with these designs replacing Intel chips in Macs in 2020. The PA6T-1682M processor would later be used by

6204-475: 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

6298-548: 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

6392-448: The instruction of one thread can be executed out of order and/or in parallel with the instruction of a different one. Also, one independent thread will not produce a pipeline bubble in the code stream of a different one, for example, due to a branch. Superscalar processors differ from multi-core processors in that the several execution units are not entire processors. A single processor is composed of finer-grained execution units such as

6486-452: The instructions to try to avoid pipeline stalls and increase parallel execution. Available performance improvement from superscalar techniques is limited by three key areas: Existing binary executable programs have varying degrees of intrinsic parallelism. In some cases instructions are not dependent on each other and can be executed simultaneously. In other cases they are inter-dependent: one instruction impacts either resources or results of

6580-507: 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

6674-549: 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

6768-441: The latter (pipeline) executes multiple instructions in the same execution unit in parallel by dividing the execution unit into different phases. In the "Simple superscalar pipeline" figure, fetching two instructions at the same time is superscaling, and fetching the next two before the first pair has been written back is pipelining. The superscalar technique is traditionally associated with several identifying characteristics (within

6862-567: The liquid-cooled machines have a sticker inside warning about the possibility of leakage. When P.A. Semi announced the preliminary pre-production plan of PWRficient processor, there had been persistent rumors that Apple would prepare for its use in its professional line of personal computers. In 2006, The Register reported that P.A. Semi had formed a tight relationship with Apple, which would result in P.A. Semi promptly delivering processor chips for Apple's personal computer notebook line and possibly desktops. Even in 2006, Apple did not have

6956-450: 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

7050-463: The more rigid methods used in the simpler P5 Pentium ; it also simplified speculative execution and allowed higher clock frequencies compared to designs such as the advanced Cyrix 6x86 . The simplest processors are scalar processors. Each instruction executed by a scalar processor typically manipulates one or two data items at a time. By contrast, each instruction executed by a vector processor operates simultaneously on many data items. An analogy

7144-413: The noise problems did not prevent the affected computers from working, they were problematic for audio professionals and enthusiasts, especially for the liquid-cooled models, which had been expressly designed as mechanically quiet for discerning listeners. A common problem among single processor G5s was the cyclic expansion and contraction of a metal plate soldered to the Logic Board connecting all eight of

7238-699: The number of units has increased. While early superscalar CPUs would have two ALUs and a single FPU , a later design such as the PowerPC 970 includes four ALUs, two FPUs, and two SIMD units. If the dispatcher is ineffective at keeping all of these units fed with instructions, the performance of the system will be no better than that of a simpler, cheaper design. A superscalar processor usually sustains an execution rate in excess of one instruction per machine cycle . But merely processing multiple instructions concurrently does not make an architecture superscalar, since pipelined , multiprocessor or multi-core architectures also achieve that, but with different methods. In

7332-468: The other. The instructions a = b + c; d = e + f can be run in parallel because none of the results depend on other calculations. However, the instructions a = b + c; b = e + f might not be runnable in parallel, depending on the order in which the instructions complete while they move through the units. Although the instruction stream may contain no inter-instruction dependencies, a superscalar CPU must nonetheless check for that possibility, since there

7426-503: 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

7520-576: The processor and the other from the processor. These result in a total bandwidth of up to 20 GB/s. The processor at the heart of the Power Mac G5 has a " superscalar , superpipelined" execution core that can handle up to 216 in-flight instructions, and uses a 128-bit , 162-instruction SIMD unit ( AltiVec ). All modern 32-bit x86 processors since the Pentium Pro have the Physical Address Extension (PAE) feature, which permits them to use

7614-493: 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

7708-432: The seepage is so slight that it was almost impossible to detect without dismantling the entire computer. Later models (only the 2.7 GHz) were equipped with a Panasonic liquid cooling system which was much more reliable. The liquid cooling system fits into the case where the heat sinks would normally go, so there is no easy way to distinguish the liquid-cooled versions from the air-cooled, although most, but not all, of

7802-399: The system turned out to be subject to coolant leakage, made worse by the system's use of GM Dexcool coolant, which is more corrosive than regular automotive coolant. If not caught in time, the leakage could destroy the processors, logic board, and even corrode the aluminum casing itself. While leakage was sometimes detectable by drops of green coolant in or beneath the machine, in many machines

7896-418: 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

7990-564: The top five supercomputers that year. The computer was soon dismantled and replaced with a new cluster made of an equal number of Xserve G5 rack-mounted servers, which also used the G5 chip running at 2.3 GHz. The PowerPC G5 (called the PowerPC 970 by its manufacturer, IBM ) is based upon IBM's 64-bit POWER4 microprocessor. At the Power Mac G5's introduction, Apple announced a partnership with IBM in which IBM would continue to produce PowerPC variants of their POWER processors. According to IBM's Dr. John E. Kelly, "The goal of this partnership

8084-477: The traditional uniformity of the instruction set favors superscalar dispatch (this was why RISC designs were faster than CISC designs through the 1980s and into the 1990s, and it's far more complicated to do multiple dispatch when instructions have variable bit length). Except for CPUs used in low-power applications, embedded systems , and battery -powered devices, essentially all general-purpose CPUs developed since about 1998 are superscalar. The P5 Pentium

8178-500: 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

8272-681: 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

8366-401: 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

8460-425: Was manufactured using IBM CMOS 9S at 130 nm fabrication process. CMOS 9S is the combination of SOI , low-k dielectric insulation, and copper interconnect technology, which were invented at IBM research in the mid-1990s. Subsequent revisions of the "G5" processor have included IBM's PowerPC 970FX (same basic design on a 90 nm process), and the PowerPC 970MP (essentially two 970FX cores on one die). Apple refers to

8554-413: Was not recommended by Apple. This noise problem was not fixed until the dual core generation of G5s was produced, however it did not affect the "Late 2004" model (at least there have never been any reports). The power draw fluctuation was later attributed to the lack of power management features in the single-core processors. Apple eventually posted the chirping bug information on its support site. Although

8648-453: 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

8742-455: Was the first superscalar x86 processor; the Nx586 , P6 Pentium Pro and AMD K5 were among the first designs which decode x86 -instructions asynchronously into dynamic microcode -like micro-op sequences prior to actual execution on a superscalar microarchitecture ; this opened up for dynamic scheduling of buffered partial instructions and enabled more parallelism to be extracted compared to

8836-490: 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

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