Microsoft Windows is a group of several graphical operating system families, all of which are developed and sold by Microsoft. Each family caters to a certain sector of the computing industry. Active Windows families include Windows Embedded. Defunct Windows families include Windows Mobile and Windows Phone. Microsoft introduced an operating environment named Windows on November 20, 1985, as a graphical operating system shell for MS-DOS in response to the growing interest in graphical user interfaces. Microsoft Windows came to dominate the world's personal computer market with over 90% market share, overtaking Mac OS, introduced in 1984. Apple came to see Windows as an unfair encroachment on their innovation in GUI development as implemented on products such as the Lisa and Macintosh. On PCs, Windows is still the most popular operating system. However, in 2014, Microsoft admitted losing the majority of the overall operating system market to Android, because of the massive growth in sales of Android smartphones.
In 2014, the number of Windows devices sold was less than 25 %. This comparison however may not be relevant, as the two operating systems traditionally target different platforms. Still, numbers for server use of Windows show one third market share, similar to that for end user use; as of October 2018, the most recent version of Windows for PCs, tablets and embedded devices is Windows 10. The most recent versions for server computers is Windows Server 2019. A specialized version of Windows runs on the Xbox One video game console. Microsoft, the developer of Windows, has registered several trademarks, each of which denote a family of Windows operating systems that target a specific sector of the computing industry; as of 2014, the following Windows families are being developed: Windows NT: Started as a family of operating systems with Windows NT 3.1, an operating system for server computers and workstations. It now consists of three operating system subfamilies that are released at the same time and share the same kernel: Windows: The operating system for mainstream personal computers and smartphones.
The latest version is Windows 10. The main competitor of this family is macOS by Apple for personal computers and Android for mobile devices. Windows Server: The operating system for server computers; the latest version is Windows Server 2019. Unlike its client sibling, it has adopted a strong naming scheme; the main competitor of this family is Linux. Windows PE: A lightweight version of its Windows sibling, meant to operate as a live operating system, used for installing Windows on bare-metal computers, recovery or troubleshooting purposes; the latest version is Windows PE 10. Windows IoT: Initially, Microsoft developed Windows CE as a general-purpose operating system for every device, too resource-limited to be called a full-fledged computer. However, Windows CE was renamed Windows Embedded Compact and was folded under Windows Compact trademark which consists of Windows Embedded Industry, Windows Embedded Professional, Windows Embedded Standard, Windows Embedded Handheld and Windows Embedded Automotive.
The following Windows families are no longer being developed: Windows 9x: An operating system that targeted consumers market. Discontinued because of suboptimal performance. Microsoft now caters to the consumer market with Windows NT. Windows Mobile: The predecessor to Windows Phone, it was a mobile phone operating system; the first version was called Pocket PC 2000. The last version is Windows Mobile 6.5. Windows Phone: An operating system sold only to manufacturers of smartphones; the first version was Windows Phone 7, followed by Windows Phone 8, the last version Windows Phone 8.1. It was succeeded by Windows 10 Mobile; the term Windows collectively describes any or all of several generations of Microsoft operating system products. These products are categorized as follows: The history of Windows dates back to 1981, when Microsoft started work on a program called "Interface Manager", it was announced in November 1983 under the name "Windows", but Windows 1.0 was not released until November 1985.
Windows 1.0 was to achieved little popularity. Windows 1.0 is not a complete operating system. The shell of Windows 1.0 is a program known as the MS-DOS Executive. Components included Calculator, Cardfile, Clipboard viewer, Control Panel, Paint, Reversi and Write. Windows 1.0 does not allow overlapping windows. Instead all windows are tiled. Only modal dialog boxes may appear over other windows. Microsoft sold as included Windows Development libraries with the C development environment, which included numerous windows samples. Windows 2.0 was released in December 1987, was more popular than its predecessor. It features several improvements to the user memory management. Windows 2.03 changed the OS from tiled windows to overlapping windows. The result of this change led to Apple Computer filing a suit against Microsoft alleging infringement on Apple's copyrights. Windows 2.0
HP-UX is Hewlett Packard Enterprise's proprietary implementation of the Unix operating system, based on UNIX System V and first released in 1984. Recent versions support the HP 9000 series of computer systems, based on the PA-RISC instruction set architecture, HP Integrity systems, based on Intel's Itanium architecture. Earlier versions of HP-UX supported the HP Integral PC and HP 9000 Series 200, 300, 400 computer systems based on the Motorola 68000 series of processors, as well as the HP 9000 Series 500 computers based on HP's proprietary FOCUS architecture. HP-UX was the first Unix to offer access control lists for file access permissions as an alternative to the standard Unix permissions system. HP-UX was among the first Unix systems to include a built-in logical volume manager. HP has had a long partnership with Veritas Software, uses VxFS as the primary file system, it is one of six commercial operating systems that have versions certified to The Open Group's UNIX 03 standard. HP-UX 11i offers a common root disk for its clustered file system.
HP Serviceguard is the cluster solution for HP-UX. HP Global Workload Management adjusts workloads to optimize performance, integrates with Instant Capacity on Demand so installed resources can be paid for in 30-minute increments as needed for peak workload demands. HP-UX offers operating system-level virtualization features such as hardware partitions, isolated OS virtual partitions on cell-based servers, HP Integrity Virtual Machines on all Integrity servers. HPVM supports guests running on HP-UX 11i v3 hosts – guests can run Linux, OpenVMS 8.4 or HP-UX. HP supports online VM guest migration, where encryption can secure the guest contents during migration. HP-UX 11i v3 scales as follows: 256 processor cores 8 TB main memory 32 TB maximum file system 16 TB maximum file size 128 million ZB—16 million logical units each up to 8ZB. "HP-UX 11i v3". Retrieved 2017-10-31; the 11i v2 release introduced kernel-based intrusion detection, strong random number generation, stack buffer overflow protection, security partitioning, role-based access management, various open-source security tools.
HP classifies the operating system's security features into three categories: data and identity: Release 6.x introduced the context dependent files feature, a method of allowing a fileserver to serve different configurations and binaries to different client machines in a heterogeneous environment. A directory containing such files had its suid bit set and was made hidden from both ordinary and root processes under normal use; such a scheme was sometimes exploited by intruders to hide malicious data. CDFs and the CDF filesystem were dropped with release 10.0. HP-UX operating systems supports a variety of PA-RISC systems; the 11.0 added support for Integrity-based servers for the transition from PA-RISC to Itanium. HP-UX 11i v1.5 is the first version. On the introduction of HP-UX 11i v2 the operating system supported both of these architectures. HP-UX 11i supports HP Integrity Servers of HP BL server blade family; these servers use the Intel Itanium architecture. HP-UX 11i v2 and 11i v3 support HP's CX series servers.
CX stands for carrier grade and is used for telco industry with -48V DC support and is NEBS certified. Both of these systems are discontinued. HP-UX supports HP's RX series of servers. Prior to the release of HP-UX version 11.11, HP used a decimal version numbering scheme with the first number giving the major release and the number following the decimal showing the minor release. With 11.11, HP made a marketing decision to name their releases 11i followed by a v for the version. The i was intended to indicate the OS is Internet-enabled, but the effective result was a dual version-numbering scheme. 1.0 First release for HP 9000 Series 500. HP-UX for Series 500 was different that HP-UX for any other HP machines, as it was layered atop a Series 500 specific operating system called SUNOS. 1.0 AT&T System III based. Support for the HP Integral PC; the kernel runs from ROM. 2.0 First release for HP's early Motorola 68000-based workstations 5.0 ROM-based AT&T System V for the HP Integral PC. Distinct from a HP-UX 5.x for Series 200/300.
3.x HP 9000 Series 600/800 only. Note: 2.x/3.x were developed in parallel with 5.x/6.x, so, for example, 3.x was contemporary with 6.x. The two lines were united at HP-UX 7.x. 6.x Support for HP 9000 Series 300 only. Introduced sockets from 4.3BSD. This version introduced the above-discussed context dependent files, which were removed in release 10 because of their security risks. 7.x Support for HP 9000 Series 300/400, 600/700 /800 HP systems. Provided OSF/Motif. 8.x Support for HP 9000 Series 300/400 600/700/800 systems. Shared libraries introduced. 9.x 9.00, 9.02, 9.04, 9.01, 9.03, 9.05, 9.07, 9.08, 9.09, 9.09+, 9.10. These provided support for the HP 9000 800 systems. Introduced System Administration Manager; the Logical Volume Manager was presented in 9.00 for the Series 800. 10.0 This major release saw a convergence of the operating system between the HP 9000 Series 700 and Series 800 systems, dropping suppor
Network topology is the arrangement of the elements of a communication network. Network topology can be used to define or describe the arrangement of various types of telecommunication networks, including command and control radio networks, industrial fieldbusses, computer networks. Network topology is the topological structure of a network and may be depicted physically or logically, it is an application of graph theory wherein communicating devices are modeled as nodes and the connections between the devices are modeled as links or lines between the nodes. Physical topology is the placement of the various components of a network, while logical topology illustrates how data flows within a network. Distances between nodes, physical interconnections, transmission rates, or signal types may differ between two different networks, yet their topologies may be identical. A network’s physical topology is a particular concern of the physical layer of the OSI model. Examples of network topologies are found in local area networks, a common computer network installation.
Any given node in the LAN has one or more physical links to other devices in the network. A wide variety of physical topologies have been used in LANs, including ring, bus and star. Conversely, mapping the data flow between the components determines the logical topology of the network. In comparison, Controller Area Networks, common in vehicles, are distributed control system networks of one or more controllers interconnected with sensors and actuators over, invariably, a physical bus topology. Two basic categories of network topologies exist, logical topologies; the transmission medium layout used to link devices is the physical topology of the network. For conductive or fiber optical mediums, this refers to the layout of cabling, the locations of nodes, the links between the nodes and the cabling; the physical topology of a network is determined by the capabilities of the network access devices and media, the level of control or fault tolerance desired, the cost associated with cabling or telecommunication circuits.
In contrast, logical topology is the way that the signals act on the network media, or the way that the data passes through the network from one device to the next without regard to the physical interconnection of the devices. A network's logical topology is not the same as its physical topology. For example, the original twisted pair Ethernet using repeater hubs was a logical bus topology carried on a physical star topology. Token ring is wired as a physical star from the media access unit. Physically, AFDX can be a cascaded star topology of multiple dual redundant Ethernet switches. Logical topologies are closely associated with media access control methods and protocols; some networks are able to dynamically change their logical topology through configuration changes to their routers and switches. The transmission media used to link devices to form a computer network include electrical cables, optical fiber, radio waves. In the OSI model, these are defined at layers 2 -- the physical layer and the data link layer.
A adopted family of transmission media used in local area network technology is collectively known as Ethernet. The media and protocol standards that enable communication between networked devices over Ethernet are defined by IEEE 802.3. Ethernet transmits data over both fiber cables. Wireless LAN standards use radio waves. Power line communication uses a building's power cabling to transmit data; the orders of the following wired technologies are from slowest to fastest transmission speed. Coaxial cable is used for cable television systems, office buildings, other work-sites for local area networks; the cables consist of copper or aluminum wire surrounded by an insulating layer, which itself is surrounded by a conductive layer. The insulation helps minimize distortion. Transmission speed ranges from 200 million bits per second to more than 500 million bits per second. ITU-T G.hn technology uses existing home wiring to create a high-speed local area network. Signal traces on printed circuit boards are common for board-level serial communication between certain types integrated circuits, a common example being SPI.
Ribbon cable has been a cost-effective media for serial protocols within metallic enclosures or rolled within copper braid or foil, over short distances, or at lower data rates. Several serial network protocols can be deployed without shielded or twisted pair cabling, that is, with "flat" or "ribbon" cable, or a hybrid flat/twisted ribbon cable, should EMC, bandwidth constraints permit: RS-232, RS-422, RS-485, CAN, GPIB, SCSI, etc. Twisted pair wire is the most used medium for all telecommunication. Twisted-pair cabling consist of copper wires. Ordinary telephone wires consist of two insulated copper wires twisted into pairs. Computer network cablin
A communication channel or channel refers either to a physical transmission medium such as a wire, or to a logical connection over a multiplexed medium such as a radio channel in telecommunications and computer networking. A channel is used to convey an information signal, for example a digital bit stream, from one or several senders to one or several receivers. A channel has a certain capacity for transmitting information measured by its bandwidth in Hz or its data rate in bits per second. Communicating data from one location to another requires some form of medium; these pathways, called communication channels, use two types of media: broadcast. Cable or wire line media use physical wires of cables to transmit data and information. Twisted-pair wire and coaxial cables are made of copper, fiber-optic cable is made of glass. In information theory, a channel refers to a theoretical channel model with certain error characteristics. In this more general view, a storage device is a kind of channel, which can be sent to and received from.
Examples of communications channels include: A connection between initiating and terminating nodes of a circuit. A single path provided by a transmission medium via either physical separation, such as by multipair cable or electrical separation, such as by frequency-division or time-division multiplexing. A path for conveying electrical or electromagnetic signals distinguished from other parallel paths. A storage which can communicate a message over time as well as space The portion of a storage medium, such as a track or band, accessible to a given reading or writing station or head. A buffer from which messages can be'put' and'got'. See Actor model and process calculi for discussion on the use of channels. In a communications system, the physical or logical link that connects a data source to a data sink. A specific radio frequency, pair or band of frequencies named with a letter, number, or codeword, allocated by international agreement. Examples: Marine VHF radio uses some 88 channels in the VHF band for two-way FM voice communication.
Channel 16, for example, is 156.800 MHz. In the US, seven additional channels, WX1 - WX7, are allocated for weather broadcasts. Television channels such as North American TV Channel 2 = 55.25 MHz, Channel 13 = 211.25 MHz. Each channel is 6 MHz wide; this was based on the bandwidth required by older analog television signals. Since 2006 television broadcasting has switched to digital modulation which uses image compression to transmit a television signal in a much smaller bandwidth, so each of these "physical channels" has been divided into multiple "virtual channels" each carrying a DTV channel. Wi-Fi uses 13 channels from 2412 MHz to 2484 MHz in 5 MHz steps, in the ISM bands; the radio channel between an amateur radio repeater and a ham uses two frequencies 600 kHz apart. For example, a repeater that transmits on 146.94 MHz listens for a ham transmitting on 146.34 MHz. All of these communications channels share the property; the information is carried through the channel by a signal. A channel can be modelled physically by trying to calculate the physical processes which modify the transmitted signal.
For example, in wireless communications the channel can be modelled by calculating the reflection off every object in the environment. A sequence of random numbers might be added in to simulate external interference and/or electronic noise in the receiver. Statistically a communication channel is modelled as a triple consisting of an input alphabet, an output alphabet, for each pair of input and output elements a transition probability p. Semantically, the transition probability is the probability that the symbol o is received given that i was transmitted over the channel. Statistical and physical modelling can be combined. For example, in wireless communications the channel is modelled by a random attenuation of the transmitted signal, followed by additive noise; the attenuation term is a simplification of the underlying physical processes and captures the change in signal power over the course of the transmission. The noise in the model electronic noise in the receiver. If the attenuation term is complex it describes the relative time a signal takes to get through the channel.
The statistics of the random attenuation are decided by previous measurements or physical simulations. Channel models may be continuous channel models in that there is no limit to how their values may be defined. Communication channels are studied in a discrete-alphabet setting; this corresponds to abstracting a real world communication system in which the analog → digital and digital → analog blocks are out of the control of the designer. The mathematical model consists of a transition probability that specifies an output distribution for each possible sequence of channel inputs. In information theory, it is common to start with memoryless channels in which the output probability distribution only depends on the current channel input. A channel model may either be analog. In a digital channel model, the transmitted message is modelled as a digital signal at a certain protocol layer. Underlying protocol layers, such as the physical layer transmission technique, is replaced by a simplified model.
The model may reflect channel performance measures such as bit rate, bit errors, latency/delay, delay jitter, etc. Examples of digital channel models are: Binary symmetric channel, a discrete memoryless channel with a
Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California, in the Silicon Valley. It is the world's second largest and second highest valued semiconductor chip manufacturer based on revenue after being overtaken by Samsung, is the inventor of the x86 series of microprocessors, the processors found in most personal computers. Intel ranked No. 46 in the 2018 Fortune 500 list of the largest United States corporations by total revenue. Intel supplies processors for computer system manufacturers such as Apple, Lenovo, HP, Dell. Intel manufactures motherboard chipsets, network interface controllers and integrated circuits, flash memory, graphics chips, embedded processors and other devices related to communications and computing. Intel Corporation was founded on July 18, 1968, by semiconductor pioneers Robert Noyce and Gordon Moore, associated with the executive leadership and vision of Andrew Grove; the company's name was conceived as portmanteau of the words integrated and electronics, with co-founder Noyce having been a key inventor of the integrated circuit.
The fact that "intel" is the term for intelligence information made the name appropriate. Intel was an early developer of SRAM and DRAM memory chips, which represented the majority of its business until 1981. Although Intel created the world's first commercial microprocessor chip in 1971, it was not until the success of the personal computer that this became its primary business. During the 1990s, Intel invested in new microprocessor designs fostering the rapid growth of the computer industry. During this period Intel became the dominant supplier of microprocessors for PCs and was known for aggressive and anti-competitive tactics in defense of its market position against Advanced Micro Devices, as well as a struggle with Microsoft for control over the direction of the PC industry; the Open Source Technology Center at Intel hosts PowerTOP and LatencyTOP, supports other open-source projects such as Wayland, Mesa3D, Intel Array Building Blocks, Threading Building Blocks, Xen. Client Computing Group – 55% of 2016 revenues – produces hardware components used in desktop and notebook computers.
Data Center Group – 29% of 2016 revenues – produces hardware components used in server and storage platforms. Internet of Things Group – 5% of 2016 revenues – offers platforms designed for retail, industrial and home use. Non-Volatile Memory Solutions Group – 4% of 2016 revenues – manufactures NAND flash memory and 3D XPoint, branded as Optane, products used in solid-state drives. Intel Security Group – 4% of 2016 revenues – produces software security, antivirus software. Programmable Solutions Group – 3% of 2016 revenues – manufactures programmable semiconductors. In 2017, Dell accounted for about 16% of Intel's total revenues, Lenovo accounted for 13% of total revenues, HP Inc. accounted for 11% of total revenues. According to IDC, while Intel enjoyed the biggest market share in both the overall worldwide PC microprocessor market and the mobile PC microprocessor in the second quarter of 2011, the numbers decreased by 1.5% and 1.9% compared to the first quarter of 2011. In the 1980s, Intel was among the top ten sellers of semiconductors in the world.
In 1992, Intel became the biggest chip maker by revenue and has held the position since. Other top semiconductor companies include TSMC, Advanced Micro Devices, Texas Instruments, Toshiba and STMicroelectronics. Competitors in PC chipsets include Advanced Micro Devices, VIA Technologies, Silicon Integrated Systems, Nvidia. Intel's competitors in networking include NXP Semiconductors, Broadcom Limited, Marvell Technology Group and Applied Micro Circuits Corporation, competitors in flash memory include Spansion, Qimonda, Toshiba, STMicroelectronics, SK Hynix; the only major competitor in the x86 processor market is Advanced Micro Devices, with which Intel has had full cross-licensing agreements since 1976: each partner can use the other's patented technological innovations without charge after a certain time. However, the cross-licensing agreement is canceled in the event of takeover; some smaller competitors such as VIA Technologies produce low-power x86 processors for small factor computers and portable equipment.
However, the advent of such mobile computing devices, in particular, has in recent years led to a decline in PC sales. Since over 95% of the world's smartphones use processors designed by ARM Holdings, ARM has become a major competitor for Intel's processor market. ARM is planning to make inroads into the PC and server market. Intel has been involved in several disputes regarding violation of antitrust laws, which are noted below. Intel was founded in Mountain View, California, in 1968 by Gordon E. Moore, a chemist, Robert Noyce, a physicist and co-inventor of the integrated circuit. Arthur Rock helped. Moore and Noyce had left Fairchild Semiconductor to found Intel. Rock was not an employee; the total initial investment in Intel was $10,000 from Rock. Just 2 years Intel became a public company via an initial public offering, raising $6.8 million. Intel's third employee was Andy Grove, a chemical engineer, who ran the company through much of the 1980s and the high-growth 1990s. In dec
International Business Machines Corporation is an American multinational information technology company headquartered in Armonk, New York, with operations in over 170 countries. The company began in 1911, founded in Endicott, New York, as the Computing-Tabulating-Recording Company and was renamed "International Business Machines" in 1924. IBM produces and sells computer hardware and software, provides hosting and consulting services in areas ranging from mainframe computers to nanotechnology. IBM is a major research organization, holding the record for most U. S. patents generated by a business for 26 consecutive years. Inventions by IBM include the automated teller machine, the floppy disk, the hard disk drive, the magnetic stripe card, the relational database, the SQL programming language, the UPC barcode, dynamic random-access memory; the IBM mainframe, exemplified by the System/360, was the dominant computing platform during the 1960s and 1970s. IBM has continually shifted business operations by focusing on higher-value, more profitable markets.
This includes spinning off printer manufacturer Lexmark in 1991 and the sale of personal computer and x86-based server businesses to Lenovo, acquiring companies such as PwC Consulting, SPSS, The Weather Company, Red Hat. In 2014, IBM announced that it would go "fabless", continuing to design semiconductors, but offloading manufacturing to GlobalFoundries. Nicknamed Big Blue, IBM is one of 30 companies included in the Dow Jones Industrial Average and one of the world's largest employers, with over 380,000 employees, known as "IBMers". At least 70% of IBMers are based outside the United States, the country with the largest number of IBMers is India. IBM employees have been awarded five Nobel Prizes, six Turing Awards, ten National Medals of Technology and five National Medals of Science. In the 1880s, technologies emerged that would form the core of International Business Machines. Julius E. Pitrap patented the computing scale in 1885. On June 16, 1911, their four companies were amalgamated in New York State by Charles Ranlett Flint forming a fifth company, the Computing-Tabulating-Recording Company based in Endicott, New York.
The five companies had offices and plants in Endicott and Binghamton, New York. C.. They manufactured machinery for sale and lease, ranging from commercial scales and industrial time recorders and cheese slicers, to tabulators and punched cards. Thomas J. Watson, Sr. fired from the National Cash Register Company by John Henry Patterson, called on Flint and, in 1914, was offered a position at CTR. Watson joined CTR as General Manager 11 months was made President when court cases relating to his time at NCR were resolved. Having learned Patterson's pioneering business practices, Watson proceeded to put the stamp of NCR onto CTR's companies, he implemented sales conventions, "generous sales incentives, a focus on customer service, an insistence on well-groomed, dark-suited salesmen and had an evangelical fervor for instilling company pride and loyalty in every worker". His favorite slogan, "THINK", became a mantra for each company's employees. During Watson's first four years, revenues reached $9 million and the company's operations expanded to Europe, South America and Australia.
Watson never liked the clumsy hyphenated name "Computing-Tabulating-Recording Company" and on February 14, 1924 chose to replace it with the more expansive title "International Business Machines". By 1933 most of the subsidiaries had been merged into one company, IBM. In 1937, IBM's tabulating equipment enabled organizations to process unprecedented amounts of data, its clients including the U. S. Government, during its first effort to maintain the employment records for 26 million people pursuant to the Social Security Act, the tracking of persecuted groups by Hitler's Third Reich through the German subsidiary Dehomag. In 1949, Thomas Watson, Sr. created IBM World Trade Corporation, a subsidiary of IBM focused on foreign operations. In 1952, he stepped down after 40 years at the company helm, his son Thomas Watson, Jr. was named president. In 1956, the company demonstrated the first practical example of artificial intelligence when Arthur L. Samuel of IBM's Poughkeepsie, New York, laboratory programmed an IBM 704 not to play checkers but "learn" from its own experience.
In 1957, the FORTRAN scientific programming language was developed. In 1961, IBM developed the SABRE reservation system for American Airlines and introduced the successful Selectric typewriter. In 1963, IBM employees and computers helped. A year it moved its corporate headquarters from New York City to Armonk, New York; the latter half of the 1960s saw IBM continue its support of space exploration, participating in the 1965 Gemini flights, 1966 Saturn flights and 1969 lunar mission. On April 7, 1964, IBM announced the first computer system family, the IBM System/360, it spanned the complete range of commercial and scientific applications from large to small, allowing companies for the first time to upgrade to models with greater computing capability without having to rewrite their applications. It was followed by the IBM System/370 in 1970. Together the
Dell is an American multinational computer technology company based in Round Rock, United States, that develops, sells and supports computers and related products and services. Named after its founder, Michael Dell, the company is one of the largest technological corporations in the world, employing more than 145,000 people in the U. S. and around the world. Dell sells personal computers, data storage devices, network switches, computer peripherals, HDTVs, printers, MP3 players, electronics built by other manufacturers; the company is well known for its innovations in supply chain management and electronic commerce its direct-sales model and its "build-to-order" or "configure to order" approach to manufacturing—delivering individual PCs configured to customer specifications. Dell was a pure hardware vendor for much of its existence, but with the acquisition in 2009 of Perot Systems, Dell entered the market for IT services; the company has since made additional acquisitions in storage and networking systems, with the aim of expanding their portfolio from offering computers only to delivering complete solutions for enterprise customers.
Dell was listed at number 51 in the Fortune 500 list, until 2014. After going private in 2013, the newly confidential nature of its financial information prevents the company from being ranked by Fortune. In 2015, it was the third largest PC vendor in the world after Lenovo and HP. Dell is the largest shipper of PC monitors worldwide. Dell is the sixth largest company in Texas by total revenue, according to Fortune magazine, it is the second largest non-oil company in Texas – behind AT&T – and the largest company in the Greater Austin area. It was a publicly traded company, as well as a component of the NASDAQ-100 and S&P 500, until it was taken private in a leveraged buyout which closed on October 30, 2013. In 2015, Dell acquired the enterprise technology firm EMC Corporation. Dell traces its origins to 1984, when Michael Dell created Dell Computer Corporation, which at the time did business as PC's Limited, while a student of the University of Texas at Austin; the dorm-room headquartered company sold IBM PC-compatible computers built from stock components.
Dell dropped out of school to focus full-time on his fledgling business, after getting $1,000 in expansion-capital from his family. In 1985, the company produced the first computer of its own design, the Turbo PC, which sold for $795. PC's Limited advertised its systems in national computer magazines for sale directly to consumers and custom assembled each ordered unit according to a selection of options; the company grossed more than $73 million in its first year of operation. In 1986, Michael Dell brought in Lee Walker, a 51-year-old venture capitalist, as president and chief operating officer, to serve as Dell's mentor and implement Dell's ideas for growing the company. Walker was instrumental in recruiting members to the board of directors when the company went public in 1988. Walker retired in 1990 due to health, Michael Dell hired Morton Meyerson, former CEO and president of Electronic Data Systems to transform the company from a fast-growing medium-sized firm into a billion-dollar enterprise.
The company dropped the PC's Limited name in 1987 to become Dell Computer Corporation and began expanding globally. In June 1988, Dell's market capitalization grew from $30 million to $80 million from its June 22 initial public offering of 3.5 million shares at $8.50 a share. In 1992, Fortune magazine included Dell Computer Corporation in its list of the world's 500 largest companies, making Michael Dell the youngest CEO of a Fortune 500 company ever. In 1993, to complement its own direct sales channel Dell planned to sell PCs at big-box retail outlets such as Wal-Mart, which would have brought in an additional $125 million in annual revenue. Bain consultant Kevin Rollins persuaded Michael Dell to pull out of these deals, believing they would be money losers in the long run. Margins at retail were thin at best and Dell left the reseller channel in 1994. Rollins would soon join Dell full-time and become the company President and CEO. Dell did not emphasize the consumer market, due to the higher costs and unacceptably low-profit margins in selling to individuals and households.
While the industry's average selling price to individuals was going down, Dell's was going up, as second- and third-time computer buyers who wanted powerful computers with multiple features and did not need much technical support were choosing Dell. Dell found an opportunity among PC-savvy individuals who liked the convenience of buying direct, customizing their PC to their means, having it delivered in days. In early 1997, Dell created an internal sales and marketing group dedicated to serving the home market and introduced a product line designed for individual users. From 1997 to 2004, Dell enjoyed steady growth and it gained market share from competitors during industry slumps. During the same period, rival PC vendors such as Compaq, Gateway, IBM, Packard Bell, AST Research struggled and left the market or were bought out. Dell surpassed Compaq to become the largest PC manufacturer in 1999. Operating costs made up only 10 percent of Dell's $35 billion in revenue in 2002, compared with 21 percent of revenue at Hewlett-Packard, 25 percent at Gateway, 46 percent at Cisco.
In 2002, when Compaq merged with Hewlett Packard, the newly combined Hewlett Packard took the top spot but struggled and Dell soon regained its lead. Dell grew the fastest in the early 2000s. Dell attained an