Computer

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For other uses, see Computer (disambiguation).

"Computer technology" redirects here. For the company, see Computer Technology Limited.

The Columbia Supercomputer, located at the NASA Ames Research Center.

An HP laptop computer

A computer is a programmable machine that receives input, stores and manipulates data, and provides output in a useful format.
While a computer can, in theory, be made out of almost anything (see misconceptions section), and mechanical examples of computers have existed through much of recorded human history, the first electronic computers were developed in the mid-20th century (1940–1945). Originally, they were the size of a large room, consuming as much power as several hundred modern personal computers (PCs).^[1] Modern computers based on integrated circuits are millions to billions of times more capable than the early machines, and occupy a fraction of the space.^[2] Simple computers are small enough to fit into mobile devices, and can be powered by a small battery. Personal computers in their various forms are icons of the Information Age and are what most people think of as "computers". However, the embedded computers found in many devices from MP3 players to fighter aircraft and from toys to industrial robots are the most numerous.

Contents [hide] 1 History of computing 1.1 Limited-function ancient computers 1.2 First general-purpose computers 1.3 Stored-program architecture 1.4 Semiconductors and microprocessors 2 Programs 2.1 Stored program architecture 2.2 Bugs 2.3 Machine code 2.4 Higher-level languages and program design 3 Function 3.1 Control unit 3.2 Arithmetic/logic unit (ALU) 3.3 Memory 3.4 Input/output (I/O) 3.5 Multitasking 3.6 Multiprocessing 3.7 Networking and the Internet 4 Misconceptions 4.1 Required technology 4.2 Computer architecture paradigms 4.3 Limited-function computers 4.4 Virtual computers 5 Further topics 5.1 Artificial intelligence 5.2 Hardware 5.3 Software 5.4 Programming languages 5.5 Professions and organizations 6 See also 7 Notes 8 References 9 External links

History of computing

Main article: History of computing hardware

The first use of the word "computer" was recorded in 1613, referring to a person who carried out calculations, or computations, and the word continued to be used in that sense until the middle of the 20th century. From the end of the 19th century onwards though, the word began to take on its more familiar meaning, describing a machine that carries out computations.^[3]

Limited-function ancient computers

The Jacquard loom, on display at the Museum of Science and Industry in Manchester, England, was one of the first programmable devices.

The history of the modern computer begins with two separate technologies—automated calculation and programmability—but no single device can be identified as the earliest computer, partly because of the inconsistent application of that term. Examples of early mechanical calculating devices include the abacus, the slide rule and arguably the astrolabe and the Antikythera mechanism, an ancient astronomical computer built by the Greeks around 80 BC.^[4] The Greek mathematician Hero of Alexandria (c. 10–70 AD) built a mechanical theater which performed a play lasting 10 minutes and was operated by a complex system of ropes and drums that might be considered to be a means of deciding which parts of the mechanism performed which actions and when.^[5] This is the essence of programmability.
The "castle clock", an astronomical clock invented by Al-Jazari in 1206, is considered to be the earliest programmable analog computer.^{[6][verification needed]} It displayed the zodiac, the solar and lunar orbits, a crescent moon-shaped pointer travelling across a gateway causing automatic doors to open every hour,^[7][8] and five robotic musicians who played music when struck by levers operated by a camshaft attached to a water wheel. The length of day and night could be re-programmed to compensate for the changing lengths of day and night throughout the year.^[6]
The Renaissance saw a re-invigoration of European mathematics and engineering. Wilhelm Schickard's 1623 device was the first of a number of mechanical calculators constructed by European engineers, but none fit the modern definition of a computer, because they could not be programmed.

Atari 8-bit computer software

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This article does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (March 2008)

Typical Atari software packaging from the 400/800 era. Most of Atari's early games, utilities and applications for the 8-bit computers used this style.

This article covers various significant pieces of software available for the Atari 8-bit home computers (400/800, XL and XE series).
For coverage of the operating system, please refer to the section within the main article.

Available programming languages

• Action! – A product of Optimized Systems Software. A high performance language that compiled to machine code, with good support for Atari's hardware. While it was popular with hobbyists, it never attained widespread acceptance, particularly since it was limited to the Atari 8-bit platform.
• Assembly language
  • Atari Assembler Editor – A 6502 assembler editor and compiler was released by Atari in a ROM cartridge.
  • Atari Macro Assembler (AMAC) – A macro assembler released by Atari Program Exchange (APX) in disk form. Copy protected.
  • MAC/65 – 6502 macro assembler/editor developed by Optimized Systems Software. Released in disk and cartridge forms.
  • Synassembler – Assembler from Synapse Software. Written by Steve Hales. Not compatible with XL/XE computers without patching.
  • Macro Assembler/Text Editor (MAE) – Assembler from Eastern House Software by Carl Moser.
  • ATMAS II
• BASIC dialects.
  • Atari BASIC – This was the original BASIC for the Atari 8-bit family. Came as a ROM cartridge with the Atari 400/800 models, but was built into the computer's ROM in later models. In the XL/XE models, BASIC could be disabled by holding down the OPTION key while booting.
  • Atari Microsoft BASIC – A version of BASIC for the Atari 8-bit family released by Atari that was more compatible with Microsoft BASIC. It was initially released on disk only. Microsoft BASIC II was the same except it was in a ROM cartridge plus extension disk.
  • Turbo Basic XL – An improved version of Atari BASIC released by a third party that is not only faster, but offers many more commands. There is also a compiler that makes Turbo-BASIC XL programs even faster by compiling them into machine-language binaries.
  • BASIC A Plus — An extended BASIC from Optimized Systems Software
  • BASIC XL — An improved BASIC from Optimized Systems Software [1]
  • BASIC XE — An enhanced version of BASIC XL from Optimized Systems Software [2]
  • Advan BASIC – This BASIC was written by William Graziano (Advan Language Designs) which was a full featured BASIC with advanced sound and player-missile support. There is also a BASIC compiler, Screen Design, and Utility package. This software was released to public domain in 2006 by William Graziano [3]
• C (Programming Language)
  • Deep Blue C – A C compiler. Written by John Palevich, APX. Based on Ron Cain's popular Small-C compiler.

• LISP
  • INTER-LISP/65
• LOGO
  • Atari LOGO
• PILOT
  • Atari PILOT
• Pascal
  • Atari Pascal – Required two drives.
  • Draper Pascal
  • Kyan Pascal
• Forth
  • fig Forth
  • X-Forth
  • ValForth

After Atari's 8-bit machines entered the realm of retrocomputing in the late 1990s, cross platform development tools such as XASM, TASM, and cc65, most commonly run on PCs, have been much used by enthusiasts to do programming intended for the machines.

Personal Computer World

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This article is about "Personal Computer World", a British computer magazine. For the unrelated U.S. magazine, see PC World (magazine). For the unrelated British retailer, see PC World (retailer).

Personal Computer World; 'new look' issue from November 2005

Personal Computer World (usually referred to as PCW) (February 1978 - June 2009) was a long-running British Computer magazine.
Although for at least the last decade it contained a high proportion of Windows PC content (reflecting the state of the IT field), the magazine's title was not intended as a specific reference to this. At its inception in 1978 'personal computer' was still a generic term, and did not refer specifically to the Wintel (or 'IBM PC compatible') platform; in fact, such a thing did not exist at the time (the original IBM PC itself would not be launched for another three years). Similarly, the magazine was unrelated to the Amstrad PCW.

Contents

[hide]

• 1 History
• 2 Closure
• 3 References
• 4 External links

  History

  PCW was founded by the Yugoslavian-born Angelo Zgorelec^[1] in 1978^[2]. PCW’s first cover model, in February 1978, was the Nascom-1, which also partly inspired Zgorelec to launch the magazine.^[3]
  PCW went monthly from the second edition. Zgorelec was publisher for the first 16 issues, and then went into partnership with Felix Dennis before selling the title to VNU. The magazine was owned by Incisive Media, which announced its closure on 8th June 2009.
  
  
  

  

  Personal Computer World April 1987 issue
  As the magazine was launched four years before the first IBM PC (reviewed in the magazine in November 1981) the magazine originally covered early self-build microcomputers. It later expanded its coverage to all kinds of microcomputers from home computers to workstations, as the industry evolved. Regular features in the earlier years of the magazine were Guy Kewney's Newsprint section, Benchtests (in-depth computer reviews), Subset, covering machine code programming, type-in program listings, Bibliofile (book reviews), the Computer Answers help column, Checkouts (brief hardware reviews) TJ's Workshop (for technical junkies), Screenplay for game reviews and Banks' Statement, the regular column from Martin Banks^[4].
  The cover style, with a single photo or illustration dominating the page, was adopted soon after its launch and continued until the early 1990s.
  PCW eagerly promoted new computers as they appeared, including the BBC Micro.^[5] The magazine also sponsored the Personal Computer World Show, an annual trade fair held in London every September from 1978 to 1989.
  The magazine underwent a major reader marketing push in 1992, resulting in its circulation figure rising from a middle-ranking 80,000 to more than 155,000 at a time when personal computing was becoming hugely popular thanks to Windows 3.1 and IBM PC clones flooding the market. PCW battled with rivals Computer Shopper, PC Direct, PC Magazine and PC Pro for several thousand pages of advertising each month, resulting in magazines that could run to over 700 pages.
  The magazine typically came with a cover-mounted CD-ROM or DVD-ROM, the latter containing additional content. Although the magazines themselves were identical, the DVD version cost more than the CD-ROM version.^{[citation needed]}
  During a brief period in 2001, the magazine was (effectively) sold as 'PCW' as part of a major overhaul of the magazine design and content, but this abbreviation was dropped from the cover after just a few issues. The content also reverted back from having been a bit more consumer electronics focused to return to its roots.
  The magazine changed (both in terms of style and content) on many occasions after its launch. The last major change took place with the November 2005 issue, when the magazine was relaunched with an updated look (including glossier paper and a redesigned layout), new features, fewer advertising pages, and a slightly higher price tag.
  Editors of the 1990s include Guy Swarbrick, Ben Tisdall, Simon Rockman, Gordon Laing and Riyad Emeran.
  

  Closure

  The magazine was closed in June 2009, with owners Incisive Media quoting poor sales and difficult economic climate for news stand titles. At the time of closing, its audited circulation figure was a mere 54,069^[6] Its last issue, dated August 2009, was published on June 8 2009.^[3] This final issue made no mention of it being the last one, and advertised a never to be published September issue. Subscribers saw their subscriptions shifted to PCW's sister magazine, Computeractive.
  At its close PCW featured a mixture of articles, mainly related to the Windows PC, with some LinuxMacintosh-related content. The news pages included reports on various new technologies. Other parts of the magazine contained reviews of computers and software. There was also a 'Hands On' section which was more tutorial-based. Advertising still made up a proportion of its bulk, although it had diminished somewhat since its peak in the 1990s. and
  The website http://www.pcw.co.uk continues, but currently consists of an aggregation of news and analysis from other websites, and does not appear to contain any original reporting or analysis.

Timex Computer 2048

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This article is about the Timex Computer 2048 (TC 2048). For the similarly-named but different ZX Spectrum-variant prototype intended for sale in North America, see Timex Sinclair 2048 (TS 2048).

Timex Computer 2048

Type	Home computer
Release date	1984
Discontinued	1989
Operating system	Sinclair BASIC
CPU	Zilog Z80A @ 3.5 MHz
Memory	48 KB

The TC 2048 or Timex Computer 2048 is a computer created by "Timex of Portugal, Lda", a branch of Timex Corporation.
It was highly compatible with the Sinclair ZX Spectrum computer, although differences in the ROM prevented 100% compatibility. Timex Portugal sold the TC 2048 in Portugal and Poland, where it was very successful. Also, a NTSC version was sold in Chile. This computer forms the basis of Andrew Owen's improved Spectrum-compatible machine, the Spectrum SE.

Technical specifications

CPU

• Zilog Z80A @ 3.50 MHz

ROM

• 16 KB

RAM

• 48 KB

Display

• Improved ULA offering additional screen modes:
  • Text: 32×24 characters (8×8 pixels, rendered in graphics mode)
  • Graphics: 256×192 pixels, 15 colours (two simultaneous colours - "attributes" - per 8×8 pixels, causing attribute clash)
  • Extended Color: 256×192 pixels, 15 colors with colour resolution of 32×192 (two simultaneous colours - "attributes" - per 1×8 pixels)
  • Dual Screen: (two 256×192 pixels screens can be placed in memory)
  • A monochrome 512×192 mode

Sound

• Beeper (1 channel, 10 octaves and 10+ semitones via internal speaker)

[By separate purchase the Joystick/Sound Unit was available to enhance sound and provide a joystick port.]
I/O

• Z80 bus in/out
• Tape audio in/out for external cassette tape storage
• RF television out
• Composite video out
• Kempston Joystick input

Storage

• External cassette tape recorder
• 1–8 external ZX Microdrives (using ZX Interface 1)
• Timex FDD (Floppy Disk Drive System Power Supply, Controller and Disk Drive in separate cases. 16K RAM, Timex Operating System (TOS))
• Timex FDD3000 (Enhanced version (all in one case) of the Timex FDD but upgraded to 64K RAM & TOS with two Hitachi 3" disk drives)

ABOUT ADSENSE?

Adsense is the program provider of advertising (ad = advertisement) of  Google.com is really "make sense", which can give results  very high (some people get thousands of dollars monthly from Adsense). This  is a breakthrough in getting income. Why? Because we usually  first have to sell something new to get money. Or if you join with  networking program, then at least you have to recruit first. But for  Adsense service, you will get the money without asking someone else to buy  or join in your network.  In other words, the person does not need to spend money. Task  You just bring as many people to your site and you will  paid if any user clicks on Google ads that you put on the website  You ... just by clicking .. they do not have to buy nothing ... although they were not paying however much clicking.  Of course there are no hard to click anything. Visitors will click on ads  google that you install because he wanted more information ... he did not  harmed anything, even his desire to get information are met. Even  with Adsense service, you can also offer on your visitors to get software for free. Visitors would love to get free software and you also get paid  by Google when visitors are downloading, installing and using  software. It's that simple! So how do we get the service 

Adsense or sign up for Adsense?  

You can join or get Adsense account with FREE ... no  pay anything. If so, from which Google can pay me? Of course Google profits in the service of others, so that there is lead behind it.  Google also launched Google Adwords service ... service where we can  advertisements on Google.com.  You often search using Google? If you enter a word or  phrase in the search field, then immediately exit sites that use the word or phrase  is not it? Note also that the right of the search results page  there are some ads that are related to your search. That  adwords ad. The installer adwor ds certainly have to pay. They charged  pay-per-1000 impressions (called CPM = Cost Per 1000 Impression), or if  there is someone who clicks their ads (called CPC = Cost Per Click). A lot of advertisers willing to pay high prices for ads  they appear in Google. Even their ads appear not only on the results page  Google searches but also on the sites of Google (which menda Google ftar  Adsense) and even in your GMail email! (Look in your gmail webmail, note  the right of the letter.) If you registered your Google Adsense then you  will receive a number of adwords ads on your web site. This means you  help Google gain income is not? So it is fitting Google  pay you well. Those who have Adsense accounts and displays  Google ads as an Adsense Publisher. While those who advertise  through service called Adwords Advertiser. This term will be found when  browse sites is Google's adsense. 

Whether this can be believed? Google.com is the world's leading search engine Yahoo.com rival.  It's been so famous the names of the portal search engine provider, which  means they are qualified, reliable, trustworthy and certainly they also  will maintain the quality of their service.  It is very important of course for those of you in choosing a business program  Any ... So for this first part, you may feel safe, even very  safe ... Your income will not be lost. If so, there is no reason for you  choose not to Adsense. 

Does this program apply internationally? Yes! Google is very fair in this case, anyone and from any country can  obtain adsense account. Unlike some other e-commerce services that  Indonesia. With what I get paid? You will be paid by check (in U.S. dollars) sent directly to the address  you (by courier in a very safe of course) and you can bank Monetize anywhere. Is it hard to get my Adsense account? Absolutely not. Just so you have a website / blog with the language  Adsense support (English, German, Spanish, Turkish, Russian, Chinese, Japanese, Korean,  and several others .. Indonesian is not allowed) I can not write in English,  Use a software translator (like TransTool - you can type in Indonesian language and the program will automatically change it in English). Send this article to your blog (do not forget to give an interesting title). You can get software translator in Mal Ambasador Kuningan or shop leading software in your area .. You do not need to write anything else! or you can try it with a free article, one more search on google with keyword free article, well ... you just copy and paste the article. But remember, Do not forget to continue to include the name of the author. Like Google Adsense AdSense for Content, Showing ads from those who put advertising on Google (Google Adwords). Display format can vary, there in the form of images, those that only the text. Both are subdivided into various forms, among others: 1. Leaderboard (elongated horizontal ad) 2. Banner 3. Scycrapper and Wide Skycrapper (elongated vertical) 4. Square, Medium Rectangle, and Large Rectangle (rectangular-shaped ad) AdSense for Search, Display Search Engine Google diwebsite facilities You. You will be paid if one is using the search engine them. ADSENSE for referrals, currently consists of 4 kinds (in the future could increase again in collaboration with Goolgle namely: 1. Referral to "Google Adsense" 2. Referral to "Google Adwords" 3. Referral to "Firefox" 4. Referral to "Picasa" When there is someone / visitors come to your site / blog, click on the link Referrals above .... Download and then install the software on computer them, then you get 1 (one) dollar (U.S.) from Google. FOR FURTHER INFORMATION PLEASE DOWNLOAD ON ADSENSE FREE IN http://adsensegallery.com/Adsense.zip EBOOKNYA

Based Computer Architecture CISC

Complex instruction set computing, or Complex Instruction Set Computer (CISC: "A set of instructions computing complex") is an architecture of instruction set in which each instruction will run some low-level operations, such as retrieval of memory, arithmetic operations, and a memory store , all at once only in a single instruction. CISC Characteristics opposite can be said with RISC. Before the process of RISC is designed for the first time, many computer architects tried to bridge the semantic gap ", namely how to make the instruction sets for high-level programming easier by providing instruction" high level "as the calling procedure, the process of repetition and complex addressing modes so that the data structure and access arrays can be combined with an instruction. Characteristics of CISC distinguished "full information" provides benefits where the size of the programs produced will be relatively small, and memory usage will be minor. Because this is the cost of making computer CISC on at that time (in 1960) become much more efficient. Indeed, after that a lot of designs that provide better results with lower costs, and also resulted in a high-level programming to be more modest, but in reality it is not always the case. For example, the complex architecture that is designed poorly (which uses micro-code to access hardware functions), will be in a situation where it's easier to improve performance by not using complex instructions (such as dialing instructions procedure), but by using a simple sequence of instructions. One reason for this is because the instruction sets of high-level, which is often encoded (for complex codes), would be quite difficult to translate back and run effectively with a limited number of transistors. Therefore, these architectures require handling more focused on processor design. At the time in which the number of transistors has been limited, resulting in the limited chances of finding alternative ways to optimize the development of the processor. Hence, the idea to use a RISC design emerged in mid 1970 (IBM Watson Research Center 801 - IBMs) 'Examples of CISC processors are the System/360, VAX, PDP-11, variants of the Motorola 68000, and AMD and Intel x86 CPU. " The term RISC and CISC is currently less well known, after seeing the further development of the design and implementation of both CISC and CISC. CISC parallel implementation for the first time, like 486 from Intel, AMD, Cyrix, and IBM has supported every instruction that is used by the processors before, although its highest efficiency only when used on a simple subset of x86 (similar to the RISC instruction set, but without limitation of storage / retrieval of data from RISC). Modern x86 processors also have to encode and split more complex instructions into several "micro-operations" internal smaller so that those instructions can be done in parallel, thus achieving high performance in a larger subset of instructions.