OS/2 is a series of computer operating systems created by Microsoft and IBM under the leadership of IBM software designer Ed Iacobucci. As a result of a feud between the two companies over how to position OS/2 relative to Microsoft's new Windows 3.1 operating environment, the two companies severed the relationship in 1992 and OS/2 development fell to IBM exclusively. The name stands for "Operating System/2", because it was introduced as part of the same generation change release as IBM's "Personal System/2" line of second-generation personal computers; the first version of OS/2 was released in December 1987 and newer versions were released until December 2001. OS/2 was intended as a protected-mode successor of PC DOS. Notably, basic system calls were modeled after MS-DOS calls; because of this heritage, OS/2 shares similarities with Unix and Windows NT. IBM discontinued its support for OS/2 on 31 December 2006. Since it has been updated and marketed under the name eComStation. In 2015 it was announced that a new OEM distribution of OS/2 would be released, to be called ArcaOS.
ArcaOS is available for purchase. The development of OS/2 began when IBM and Microsoft signed the "Joint Development Agreement" in August 1985, it was code-named "CP/DOS" and it took two years for the first product to be delivered. OS/2 1.0 was released in December. The original release is textmode-only, a GUI was introduced with OS/2 1.1 about a year later. OS/2 features an API for controlling the video display and handling keyboard and mouse events so that programmers writing for protected-mode need not call the BIOS or access hardware directly. Other development tools included a subset of the video and keyboard APIs as linkable libraries so that family mode programs are able to run under MS-DOS, and, in the OS/2 Extended Edition v1.0, a database engine called Database Manager or DBM. A task-switcher named Program Selector was available through the Ctrl-Esc hotkey combination, allowing the user to select among multitasked text-mode sessions. Communications and database-oriented extensions were delivered in 1988, as part of OS/2 1.0 Extended Edition: SNA, X.25/APPC/LU 6.2, LAN Manager, Query Manager, SQL.
The promised user interface, Presentation Manager, was introduced with OS/2 1.1 in October 1988. It had a similar user interface to Windows 2.1, released in May of that year.. The Extended Edition of 1.1, sold only through IBM sales channels, introduced distributed database support to IBM database systems and SNA communications support to IBM mainframe networks. In 1989, Version 1.2 introduced Installable Filesystems and, the HPFS filesystem. HPFS provided a number of improvements over the older FAT file system, including long filenames and a form of alternate data streams called Extended Attributes. In addition, extended attributes were added to the FAT file system; the Extended Edition of 1.2 introduced Ethernet support. OS/2- and Windows-related books of the late 1980s acknowledged the existence of both systems and promoted OS/2 as the system of the future; the collaboration between IBM and Microsoft unravelled in 1990, between the releases of Windows 3.0 and OS/2 1.3. During this time, Windows 3.0 became a tremendous success, selling millions of copies in its first year.
Much of its success was. OS/2, on the other hand, was available only as an additional stand-alone software package. In addition, OS/2 lacked device drivers for many common devices such as printers non-IBM hardware. Windows, on the other hand, supported a much larger variety of hardware; the increasing popularity of Windows prompted Microsoft to shift its development focus from cooperating on OS/2 with IBM to building its own business based on Windows. Several technical and practical reasons contributed to this breakup; the two companies had significant differences in vision. Microsoft favored the open hardware system approach that contributed to its success on the PC. Microsoft programmers became frustrated with IBM's bureaucracy and its use of lines of code to measure programmer productivity. IBM developers complained about the terseness and lack of comments in Microsoft's code, while Microsoft developers complained that IBM's code was bloated; the two products have significant differences in API.
OS/2 was announced when Windows 2.0 was near completion, the Windows API defined. However, IBM requested that this API be changed for OS/2. Therefore, issues surrounding application compatibility appeared immediately. OS/2 designers hoped for source code conversion tools, allowing complete migration of Windows application source code to OS/2 at some point. However, OS/2 1.x did not gain enough momentum to allow vendors to avoid developing for both OS/2 and Windows in parallel. OS/2 1.x targets DOS fundamentally doesn't. IBM insisted on supporting the 80286 processor, with its 16-bit segmented memory mode, because of commitments made to customers who had purchased many 80286-based PS/2s as a result of IBM's promises surrounding OS/2; until release 2.0 in April 1992, OS/2 ran in 16-bit protected mode and therefor
An operating system is system software that manages computer hardware and software resources and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may include accounting software for cost allocation of processor time, mass storage and other resources. For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is executed directly by the hardware and makes system calls to an OS function or is interrupted by it. Operating systems are found on many devices that contain a computer – from cellular phones and video game consoles to web servers and supercomputers; the dominant desktop operating system is Microsoft Windows with a market share of around 82.74%. MacOS by Apple Inc. is in second place, the varieties of Linux are collectively in third place. In the mobile sector, use in 2017 is up to 70% of Google's Android and according to third quarter 2016 data, Android on smartphones is dominant with 87.5 percent and a growth rate 10.3 percent per year, followed by Apple's iOS with 12.1 percent and a per year decrease in market share of 5.2 percent, while other operating systems amount to just 0.3 percent.
Linux distributions are dominant in supercomputing sectors. Other specialized classes of operating systems, such as embedded and real-time systems, exist for many applications. A single-tasking system can only run one program at a time, while a multi-tasking operating system allows more than one program to be running in concurrency; this is achieved by time-sharing, where the available processor time is divided between multiple processes. These processes are each interrupted in time slices by a task-scheduling subsystem of the operating system. Multi-tasking may be characterized in co-operative types. In preemptive multitasking, the operating system slices the CPU time and dedicates a slot to each of the programs. Unix-like operating systems, such as Solaris and Linux—as well as non-Unix-like, such as AmigaOS—support preemptive multitasking. Cooperative multitasking is achieved by relying on each process to provide time to the other processes in a defined manner. 16-bit versions of Microsoft Windows used cooperative multi-tasking.
32-bit versions of both Windows NT and Win9x, used preemptive multi-tasking. Single-user operating systems have no facilities to distinguish users, but may allow multiple programs to run in tandem. A multi-user operating system extends the basic concept of multi-tasking with facilities that identify processes and resources, such as disk space, belonging to multiple users, the system permits multiple users to interact with the system at the same time. Time-sharing operating systems schedule tasks for efficient use of the system and may include accounting software for cost allocation of processor time, mass storage and other resources to multiple users. A distributed operating system manages a group of distinct computers and makes them appear to be a single computer; the development of networked computers that could be linked and communicate with each other gave rise to distributed computing. Distributed computations are carried out on more than one machine; when computers in a group work in cooperation, they form a distributed system.
In an OS, distributed and cloud computing context, templating refers to creating a single virtual machine image as a guest operating system saving it as a tool for multiple running virtual machines. The technique is used both in virtualization and cloud computing management, is common in large server warehouses. Embedded operating systems are designed to be used in embedded computer systems, they are designed to operate on small machines like PDAs with less autonomy. They are able to operate with a limited number of resources, they are compact and efficient by design. Windows CE and Minix 3 are some examples of embedded operating systems. A real-time operating system is an operating system that guarantees to process events or data by a specific moment in time. A real-time operating system may be single- or multi-tasking, but when multitasking, it uses specialized scheduling algorithms so that a deterministic nature of behavior is achieved. An event-driven system switches between tasks based on their priorities or external events while time-sharing operating systems switch tasks based on clock interrupts.
A library operating system is one in which the services that a typical operating system provides, such as networking, are provided in the form of libraries and composed with the application and configuration code to construct a unikernel: a specialized, single address space, machine image that can be deployed to cloud or embedded environments. Early computers were built to perform a series of single tasks, like a calculator. Basic operating system features were developed in the 1950s, such as resident monitor functions that could automatically run different programs in succession to speed up processing. Operating systems did not exist in their more complex forms until the early 1960s. Hardware features were added, that enabled use of runtime libraries and parallel processing; when personal computers became popular in the 1980s, operating systems were made for them similar in concept to those used on larger computers. In the 1940s, the earliest electronic digital systems had no operating systems.
Electronic systems of this time were programmed on rows of mechanical switches or by jumper wires on plug boards. These were special-purpose systems that, for example, generated ballistics tables for the military or controlled the pri
The LaserWriter is a laser printer with built-in PostScript interpreter sold by Apple Computer, Inc. from 1985 to 1988. It was one of the first laser printers available to the mass market. In combination with WYSIWYG publishing software like PageMaker, that operated on top of the graphical user interface of Macintosh computers, the LaserWriter was a key component at the beginning of the desktop publishing revolution. Laser printing traces its history to efforts by Gary Starkweather at Xerox in 1969, which resulted in a commercial system called the Xerox 9700. IBM followed this with the IBM 3800 system in 1976. Both machines were room-filling devices handling the combined output of many users. During the mid-1970s, Canon started working on similar machines, partnered with Hewlett-Packard to produce 1980's HP 2680, which filled only part of a room. Other copier companies started development of similar systems. HP introduced their first desktop model with a Ricoh engine for $12,800 in 1983. Sales of the non-networked product were unsurprisingly poor.
In 1983 Canon introduced the LBP-CX, a desktop laser printer engine using a laser diode and featuring an output resolution of 300 dpi. In 1984, HP released the first commercially available system based on the HP LaserJet. Steve Jobs of Apple Computer had seen the LPB-CX while negotiating for supplies of 3.5" floppy disk drives for the upcoming Apple Macintosh computer. Meanwhile, John Warnock had left Xerox to found Adobe Systems in order to commercialize PostScript and AppleTalk in a laser printer they intended to market. Jobs was aware of Warnock's efforts, on his return to California he started working on convincing Warnock to allow Apple to license PostScript for a new printer that Apple would sell. Negotiations between Apple and Adobe over the use of Postscript began in 1983 and an agreement was reached in December 1983, one month before Macintosh was announced. Jobs arranged for Apple to buy $2.5 million in Adobe stock. At about the same time, Jonathan Seybold introduced Paul Brainerd to Apple, where he learned of Apple's laser printer efforts and saw the potential for a new program using the Mac's GUI to produce PostScript output for the new printer.
Arranging his own funding through a venture capital firm, Brainerd formed Aldus and began development of what would become PageMaker. The VC coined the term "desktop publishing" during this time; the LaserWriter was announced at Apple's annual shareholder meeting on January 23, 1985, the same day Aldus announced PageMaker. Shipments began in March 1985 at the retail price of US$6,995 more than the HP model. However, the LaserWriter featured AppleTalk support that allowed the printer to be shared among as many as sixteen Macs, meaning that its per-user price could fall to under $450, far less expensive than HP's less-advanced model; the combination of the LaserWriter, PostScript, PageMaker and the Mac's GUI and built-in AppleTalk networking would transform the landscape of computer desktop publishing. At the time, Apple planned to release a suite of AppleTalk products as part of the Macintosh Office, with the LaserWriter being only the first component. While competing printers and their associated control languages offered some of the capabilities of PostScript, they were limited in their ability to reproduce free-form layouts, use outline fonts, or offer the level of detail and control over the page layout.
HP's own LaserJet was driven by a simple page description language, known as Printer Command Language, or PCL. The version for the LaserJet, PCL4, was adapted from earlier inkjet printers with the addition of downloadable bitmapped fonts, it lacked the power and flexibility of PostScript until several upgrades provided some level of parity. It was some time before similar products became available on other platforms, by which time the Mac had ridden the desktop publishing market to success; the LaserWriter used the same Canon CX printing engine as the HP LaserJet, as a consequence early LaserWriters and LaserJets shared the same toner cartridges and paper trays. PostScript is a complete programming language that has to be run in a suitable interpreter and sent to a software rasterizer program, all inside the printer. To support this, the LaserWriter featured a Motorola 68000 CPU running at 12 MHz, 512 kB of workspace RAM, a 1 MB frame buffer. At introduction, the LaserWriter had the most processing power in Apple’s product line—more than the 8 MHz Macintosh.
As a result, the LaserWriter was one of Apple's most expensive offerings. For implementation purposes, the LaserWriter employed a small number of medium-scale-integration Monolithic Memories PALs, no custom LSI, whereas the LaserJet employed a large number small-scale-integration Texas Instruments 74-Series gates, one custom LSI; the LaserWriter was, thereby, in the same form factor, able to provide much greater function, indeed, much greater performance, all within the same LBP-CX form factor, although the external packaging was, for marketing purposes, somewhat different. Since the cost of a LaserWriter was several times that of a dot-matrix impact printer, some means to share the printer with several Macs was desired. LANs were complex and expensive, so Apple developed its own networking scheme, LocalTalk. Based on the AppleTalk protocol stack, LocalTalk connected the LaserWriter to the Mac over an RS-422 serial port. At 230.4 kbit/s LocalTalk was slower than the Centronics PC parallel interface, but allowed several computers to share a single LaserWriter.
PostScript enabled the LaserWriter to print complex pages containing high-resolution bitmap graphics, outline fonts, vector illustrations. The LaserWriter could print more complex la
Byte was an American microcomputer magazine, influential in the late 1970s and throughout the 1980s because of its wide-ranging editorial coverage. Whereas many magazines were dedicated to specific systems or the home or business users' perspective, Byte covered developments in the entire field of "small computers and software," and sometimes other computing fields such as supercomputers and high-reliability computing. Coverage was in-depth with much technical detail, rather than user-oriented. Byte started in 1975, shortly after the first personal computers appeared as kits advertised in the back of electronics magazines. Byte was published monthly, with an initial yearly subscription price of $10. Print publication ceased in 1998 and online publication in 2013. In 1975 Wayne Green was the editor and publisher of 73 and his ex-wife, Virginia Londner Green was the Business Manager of 73 Inc. In the August 1975 issue of 73 magazine Wayne's editorial column started with this item: The response to computer-type articles in 73 has been so enthusiastic that we here in Peterborough got carried away.
On May 25th we made a deal with the publisher of a small computer hobby magazine to take over as editor of a new publication which would start in August... Byte. Carl Helmers published a series of six articles in 1974 that detailed the design and construction of his "Experimenter's Computer System", a personal computer based on the Intel 8008 microprocessor. In January 1975 this became the monthly ECS magazine with 400 subscribers; the last issue was published on May 12, 1975 and in June the subscribers were mailed a notice announcing Byte magazine. Carl wrote to another hobbyist newsletter, Micro-8 Computer User Group Newsletter, described his new job as editor of Byte magazine. I got a note in the mail about two weeks ago from Wayne Green, publisher of'73 Magazine' saying hello and why don't you come up and talk a bit; the net result of a follow up is the decision to create BYTE magazine using the facilities of Green Publishing Inc. I will end up with the editorial focus for the magazine. Virginia Londner Green had returned to 73 in the December 1974 issue and incorporated Green Publishing in March 1975.
The first five issues of Byte were published by Green Publishing and the name was changed to Byte Publications starting with the February 1976 issue. Carl Helmers was a co-owner of Byte Publications; the first four issues were produced in the offices of 73 and Wayne Green was listed as the publisher. One day in November 1975 Wayne came to work and found that the Byte magazine staff had moved out and taken the January issue with them; the February 1976 issue of Byte has a short story about the move. "After a start which reads like a romantic light opera with an episode or two reminiscent of the Keystone Cops, Byte magazine has moved into separate offices of its own." Wayne Green was not happy about losing Byte magazine so he was going to start a new one called Kilobyte. Byte trademarked KILOBYTE as a cartoon series in Byte magazine; the new magazine was called Kilobaud. There was competition and animosity between Byte Publications and 73 Inc. but both remained in the small town of Peterborough, New Hampshire.
Articles in the first issue included Which Microprocessor For You? by Hal Chamberlin, Write Your Own Assembler by Dan Fylstra and Serial Interface by Don Lancaster. Advertisements from Godbout, MITS, Processor Technology, SCELBI, Sphere appear, among others. Early articles in Byte were do-it-yourself electronic or software projects to improve small computers. A continuing feature was Ciarcia's Circuit Cellar, a column in which electronic engineer Steve Ciarcia described small projects to modify or attach to a computer. Significant articles in this period included the "Kansas City" standard for data storage on audio tape, insertion of disk drives into S-100 computers, publication of source code for various computer languages, coverage of the first microcomputer operating system, CP/M. Byte ran Microsoft's first advertisement, as "Micro-Soft", to sell a BASIC interpreter for 8080-based computers. In spring of 1979, owner/publisher Virginia Williamson sold Byte to McGraw-Hill, she became a vice president of McGraw-Hill Publications Company.
Shortly after the IBM PC was introduced, in 1981, the magazine changed editorial policies. It de-emphasized the do-it-yourself electronics and software articles, began running product reviews, it continued its wide-ranging coverage of hardware and software, but now it reported "what it does" and "how it works", not "how to do it". The editorial focus remained on home and personal computers). By the early 1980s Byte had become an "elite" magazine, seen as a peer of Rolling Stone and Playboy, others such as David Bunnell of PC Magazine aspired to emulate its reputation and success, it was the only computer publication on the 1981 Folio 400 list of largest magazines. Byte's 1982 average number of pages was 543, the number of paid advertising pages grew by more than 1,000 while most magazines' amount of advertising did not change, its circulation of 420,000 was the third highest of all computer magazines. Byte earned $9 million from revenue of $36.6 million in 1983, twice the average profit margin for the magazine industry.
It remained successful while many other magazines failed in 1984 during economic weakness in the computer industry. The October 1984 issue had about 300 pages of ads sold at an average of $6,000 per page. From 1975 to 1986 Byte covers featured the artwork of Robert Tinney. Thes
Desktop publishing is the creation of documents using page layout skills on a personal computer for print. Desktop publishing software can generate layouts and produce typographic quality text and images comparable to traditional typography and printing; this technology allows individuals and other organizations to self-publish a wide range of printed matter. Desktop publishing is the main reference for digital typography; when used skillfully, desktop publishing allows the user to produce a wide variety of materials, from menus to magazines and books, without the expense of commercial printing. Desktop publishing combines a personal computer and WYSIWYG page layout software to create publication documents on a computer for either large scale publishing or small scale local multifunction peripheral output and distribution. Desktop publishing methods provide more control over design and typography than word processing. However, word processing software has evolved to include some, though by no means all, capabilities available only with professional printing or desktop publishing.
The same DTP skills and software used for common paper and book publishing are sometimes used to create graphics for point of sale displays, promotional items, trade show exhibits, retail package designs and outdoor signs. Although what is classified as "DTP software" is limited to print and PDF publications, DTP skills aren't limited to print; the content produced by desktop publishers may be exported and used for electronic media. The job descriptions that include "DTP", such as DTP artist require skills using software for producing e-books, web content, web pages, which may involve web design or user interface design for any graphical user interface. Desktop publishing was first developed at Xerox PARC in the 1970s. A contradictory claim states that desktop publishing began in 1983 with a program developed by James Davise at a community newspaper in Philadelphia; the program Type Processor One ran on a PC using a graphics card for a WYSIWYG display and was offered commercially by Best info in 1984.
The Macintosh computer platform was introduced by Apple with much fanfare in 1984, but at the beginning, the Mac lacked DTP capabilities. The DTP market exploded in 1985 with the introduction in January of the Apple LaserWriter printer, in July with the introduction of PageMaker software from Aldus, which became the standard software application for desktop publishing. With its advanced layout features, PageMaker relegated word processors like Microsoft Word to the mere composition and editing of purely textual documents; the term "desktop publishing" is attributed to Aldus founder Paul Brainerd, who sought a marketing catchphrase to describe the small size and relative affordability of this suite of products, in contrast to the expensive commercial phototypesetting equipment of the day. Before the advent of desktop publishing, the only option available to most people for producing typed documents was a typewriter, which offered only a handful of typefaces and one or two font sizes. Indeed, one popular desktop publishing book was entitled The Mac is not a typewriter, it had to explain how a Mac could do so much more than a typewriter.
The ability to create WYSIWYG page layouts on screen and print pages containing text and graphical elements at crisp 300 dpi resolution was revolutionary for both the typesetting industry and the personal computer industry. Early 1980s desktop publishing was a primitive affair. Users of the PageMaker-LaserWriter-Macintosh 512K system endured frequent software crashes, cramped display on the Mac's tiny 512 x 342 1-bit monochrome screen, the inability to control letter-spacing and other typographic features, discrepancies between the screen display and printed output. However, it was a revolutionary combination at the time, was received with considerable acclaim. Behind-the-scenes technologies developed by Adobe Systems set the foundation for professional desktop publishing applications; the LaserWriter and LaserWriter Plus printers included high quality, scalable Adobe PostScript fonts built into their ROM memory. The LaserWriter's PostScript capability allowed publication designers to proof files on a local printer print the same file at DTP service bureaus using optical resolution 600+ ppi PostScript printers such as those from Linotronic.
The Macintosh II was released, much more suitable for desktop publishing because of its greater expandability, support for large color multi-monitor displays, its SCSI storage interface which allowed fast high-capacity hard drives to be attached to the system. Macintosh-based systems continued to dominate the market into 1986, when the GEM-based Ventura Publisher was introduced for MS-DOS computers. PageMaker's pasteboard metaphor simulated the process of creating layouts manually, but Ventura Publisher automated the layout process through its use of tags and style sheets and automatically generated indices and other body matter; this made it suitable for other long-format documents. Desktop publishing moved into the home market in 1986 with Professional Page for the Amiga, Publishing Partner for the Atari ST, GST's Timeworks Publisher on the PC and Atari ST, Calamus for the Atari TT030. Software was published for 8-bit computers like the A
International Standard Serial Number
An International Standard Serial Number is an eight-digit serial number used to uniquely identify a serial publication, such as a magazine. The ISSN is helpful in distinguishing between serials with the same title. ISSN are used in ordering, interlibrary loans, other practices in connection with serial literature; the ISSN system was first drafted as an International Organization for Standardization international standard in 1971 and published as ISO 3297 in 1975. ISO subcommittee TC 46/SC 9 is responsible for maintaining the standard; when a serial with the same content is published in more than one media type, a different ISSN is assigned to each media type. For example, many serials are published both in electronic media; the ISSN system refers to these types as electronic ISSN, respectively. Conversely, as defined in ISO 3297:2007, every serial in the ISSN system is assigned a linking ISSN the same as the ISSN assigned to the serial in its first published medium, which links together all ISSNs assigned to the serial in every medium.
The format of the ISSN is an eight digit code, divided by a hyphen into two four-digit numbers. As an integer number, it can be represented by the first seven digits; the last code digit, which may be 0-9 or an X, is a check digit. Formally, the general form of the ISSN code can be expressed as follows: NNNN-NNNC where N is in the set, a digit character, C is in; the ISSN of the journal Hearing Research, for example, is 0378-5955, where the final 5 is the check digit, C=5. To calculate the check digit, the following algorithm may be used: Calculate the sum of the first seven digits of the ISSN multiplied by its position in the number, counting from the right—that is, 8, 7, 6, 5, 4, 3, 2, respectively: 0 ⋅ 8 + 3 ⋅ 7 + 7 ⋅ 6 + 8 ⋅ 5 + 5 ⋅ 4 + 9 ⋅ 3 + 5 ⋅ 2 = 0 + 21 + 42 + 40 + 20 + 27 + 10 = 160 The modulus 11 of this sum is calculated. For calculations, an upper case X in the check digit position indicates a check digit of 10. To confirm the check digit, calculate the sum of all eight digits of the ISSN multiplied by its position in the number, counting from the right.
The modulus 11 of the sum must be 0. There is an online ISSN checker. ISSN codes are assigned by a network of ISSN National Centres located at national libraries and coordinated by the ISSN International Centre based in Paris; the International Centre is an intergovernmental organization created in 1974 through an agreement between UNESCO and the French government. The International Centre maintains a database of all ISSNs assigned worldwide, the ISDS Register otherwise known as the ISSN Register. At the end of 2016, the ISSN Register contained records for 1,943,572 items. ISSN and ISBN codes are similar in concept. An ISBN might be assigned for particular issues of a serial, in addition to the ISSN code for the serial as a whole. An ISSN, unlike the ISBN code, is an anonymous identifier associated with a serial title, containing no information as to the publisher or its location. For this reason a new ISSN is assigned to a serial each time it undergoes a major title change. Since the ISSN applies to an entire serial a new identifier, the Serial Item and Contribution Identifier, was built on top of it to allow references to specific volumes, articles, or other identifiable components.
Separate ISSNs are needed for serials in different media. Thus, the print and electronic media versions of a serial need separate ISSNs. A CD-ROM version and a web version of a serial require different ISSNs since two different media are involved. However, the same ISSN can be used for different file formats of the same online serial; this "media-oriented identification" of serials made sense in the 1970s. In the 1990s and onward, with personal computers, better screens, the Web, it makes sense to consider only content, independent of media; this "content-oriented identification" of serials was a repressed demand during a decade, but no ISSN update or initiative occurred. A natural extension for ISSN, the unique-identification of the articles in the serials, was the main demand application. An alternative serials' contents model arrived with the indecs Content Model and its application, the digital object identifier, as ISSN-independent initiative, consolidated in the 2000s. Only in 2007, ISSN-L was defined in the
IBM PC compatible
IBM PC compatible computers are computers similar to the original IBM PC, XT, AT, able to use the same software and expansion cards. Such computers used to be referred to as PC clones, or IBM clones, they duplicate exactly all the significant features of the PC architecture, facilitated by IBM's choice of commodity hardware components and various manufacturers' ability to reverse engineer the BIOS firmware using a "clean room design" technique. Columbia Data Products built the first clone of the IBM personal computer by a clean room implementation of its BIOS. Early IBM PC compatibles used the same computer bus as AT models; the IBM AT compatible bus was named the Industry Standard Architecture bus by manufacturers of compatible computers. The term "IBM PC compatible" is now a historical description only, since IBM has ended its personal computer sales. Descendants of the IBM PC compatibles comprise the majority of personal computers on the market presently with the dominant operating system being Microsoft Windows, although interoperability with the bus structure and peripherals of the original PC architecture may be limited or non-existent.
Some computers ran MS-DOS but had enough hardware differences that IBM compatible software could not be used. Only the Macintosh kept significant market share without compatibility with the IBM PC. IBM decided in 1980 to market a low-cost single-user computer as as possible in response to Apple Computer's success in the burgeoning microcomputer market. On 12 August 1981, the first IBM PC went on sale. There were three operating systems available for it; the least expensive and most popular was PC DOS made by Microsoft. In a crucial concession, IBM's agreement allowed Microsoft to sell its own version, MS-DOS, for non-IBM computers; the only component of the original PC architecture exclusive to IBM was the BIOS. IBM at first asked developers to avoid writing software that addressed the computer's hardware directly, to instead make standard calls to BIOS functions that carried out hardware-dependent operations; this software would run on any machine using MS-DOS or PC-DOS. Software that directly addressed the hardware instead of making standard calls was however.
Software addressing IBM PC hardware in this way would not run on MS-DOS machines with different hardware. The IBM PC was sold in high enough volumes to justify writing software for it, this encouraged other manufacturers to produce machines which could use the same programs, expansion cards, peripherals as the PC; the 808x computer marketplace excluded all machines which were not hardware- and software-compatible with the PC. The 640 KB barrier on "conventional" system memory available to MS-DOS is a legacy of that period. Rumors of "lookalike", compatible computers, created without IBM's approval, began immediately after the IBM PC's release. InfoWorld wrote on the first anniversary of the IBM PC that The dark side of an open system is its imitators. If the specs are clear enough for you to design peripherals, they are clear enough for you to design imitations. Apple... has patents on two important components of its systems... IBM, which has no special patents on the PC, is more vulnerable. Numerous PC-compatible machines—the grapevine says 60 or more—have begun to appear in the marketplace.
By June 1983 PC Magazine defined "PC'clone'" as "a computer accommodate the user who takes a disk home from an IBM PC, walks across the room, plugs it into the'foreign' machine". Because of a shortage of IBM PCs that year, many customers purchased clones instead. Columbia Data Products produced the first computer more or less compatible with the IBM PC standard during June 1982, soon followed by Eagle Computer. Compaq announced its first IBM PC compatible in the Compaq Portable; the Compaq was the first sewing machine-sized portable computer, 100% PC-compatible. The company could not copy the BIOS directly as a result of the court decision in Apple v. Franklin, but it could reverse-engineer the IBM BIOS and write its own BIOS using clean room design. At the same time, many manufacturers such as Tandy/RadioShack, Hewlett-Packard, Digital Equipment Corporation, Texas Instruments, Tulip and Olivetti introduced personal computers that supported MS-DOS, but were not software- or hardware-compatible with the IBM PC.
Tandy described the Tandy 2000, for example, as having a "'next generation' true 16-bit CPU", with "More speed. More disk storage. More expansion" than the IBM PC or "other MS-DOS computers". While admitting in 1984 that many MS-DOS programs did not support the computer, the company stated that "the most popular, sophisticated software on the market" was available, either or "over the next six months". Like IBM, Microsoft's intention was that application writers would write to the application programming interfaces in MS-DOS or the firmware BIOS, that this would form what would now be termed a hardware abstraction layer; each computer would have its own Original Equipment Manufacturer version of MS-DOS, customized to its hardware. Any software written for MS-DOS would operate on any MS-DOS computer, despite variations in hardware design; this expectation seemed reasonable in the computer marketplace of the time. Until Microsoft was based on computer languages such as BASIC; the established small system operating software was CP/M from Digital Research, in use both at the hobbyist level and by the more professional of t