1.
Personal computer
–
A personal computer is a multi-purpose electronic computer whose size, capabilities, and price make it feasible for individual use. PCs are intended to be operated directly by a end-user, rather than by an expert or technician. In the 2010s, PCs are typically connected to the Internet, allowing access to the World Wide Web, personal computers may be connected to a local area network, either by a cable or a wireless connection. In the 2010s, a PC may be, a multi-component desktop computer, designed for use in a location a laptop computer, designed for easy portability or a tablet computer. In the 2010s, PCs run using a system, such as Microsoft Windows, Linux. The very earliest microcomputers, equipped with a front panel, required hand-loading of a program to load programs from external storage. Before long, automatic booting from permanent read-only memory became universal, in the 2010s, users have access to a wide range of commercial software, free software and free and open-source software, which are provided in ready-to-run or ready-to-compile form. Since the early 1990s, Microsoft operating systems and Intel hardware have dominated much of the computer market, first with MS-DOS. Alternatives to Microsofts Windows operating systems occupy a minority share of the industry and these include Apples OS X and free open-source Unix-like operating systems such as Linux and Berkeley Software Distribution. Advanced Micro Devices provides the alternative to Intels processors. PC is an initialism for personal computer, some PCs, including the OLPC XOs, are equipped with x86 or x64 processors but not designed to run Microsoft Windows. PC is used in contrast with Mac, an Apple Macintosh computer and this sense of the word is used in the Get a Mac advertisement campaign that ran between 2006 and 2009, as well as its rival, Im a PC campaign, that appeared in 2008. Since Apples transition to Intel processors starting 2005, all Macintosh computers are now PCs, the “brain” may one day come down to our level and help with our income-tax and book-keeping calculations. But this is speculation and there is no sign of it so far, in the history of computing there were many examples of computers designed to be used by one person, as opposed to terminals connected to mainframe computers. Using the narrow definition of operated by one person, the first personal computer was the ENIAC which became operational in 1946 and it did not meet further definitions of affordable or easy to use. An example of an early single-user computer was the LGP-30, created in 1956 by Stan Frankel and used for science and it came with a retail price of $47, 000—equivalent to about $414,000 today. Introduced at the 1965 New York Worlds Fair, the Programma 101 was a programmable calculator described in advertisements as a desktop computer. It was manufactured by the Italian company Olivetti and invented by the Italian engineer Pier Giorgio Perotto, the Soviet MIR series of computers was developed from 1965 to 1969 in a group headed by Victor Glushkov
2.
Parallel ATA
–
Parallel ATA, originally AT Attachment, is an interface standard for the connection of storage devices such as hard disk drives, floppy disk drives, and optical disc drives in computers. The standard is maintained by the X3/INCITS committee and it uses the underlying AT Attachment and AT Attachment Packet Interface standards. The Parallel ATA standard is the result of a history of incremental technical development. The ATA interface itself evolved in stages from Western Digitals original Integrated Drive Electronics interface. As a result, many near-synonyms for ATA/ATAPI and its previous incarnations are still in informal use, in particular Extended IDE. After the introduction of Serial ATA in 2003, the original ATA was renamed to Parallel ATA, Parallel ATA cables have a maximum allowable length of only 18 in. Because of this limit, the technology normally appears as a computer storage interface. For many years, ATA provided the most common and the least expensive interface for this application and it has largely been replaced by SATA in newer systems. The PATA standard was originally conceived as the PC/AT Attachment because its primary feature was a connection to the 16-bit ISA bus introduced with the IBM PC/AT. The AT in IBM PC/AT refers to Advanced Technology, but the ATA specifications simply use the name AT Attachment, the first version of what is now called the ATA/ATAPI interface was developed by Western Digital under the name Integrated Drive Electronics. The first such drives appeared in Compaq PCs in 1986, the interface cards used to connect a parallel ATA drive to, for example, a PCI slot are not drive controllers, they are merely bridges between the host bus and the ATA interface. Since the original ATA interface is essentially just a 16-bit ISA bus in disguise, the integrated controller presented the drive to the host computer as an array of 512-byte blocks with a relatively simple command interface. All of these details of the mechanical operation of the drive were now handled by the controller on the drive itself. This also eliminated the need to design a controller that could handle many different types of drives. The host need only ask for a sector, or block, to be read or written. The interface used by these drives was standardized in 1994 as ANSI standard X3. 221-1994, after later versions of the standard were developed, this became known as ATA-1. A short-lived, seldom-used implementation of ATA was created for the IBM XT and it has been referred to as XT-IDE, XTA or XT Attachment. At the time, in combination with the drive, this was sufficient for most people
3.
Hard disk drive
–
The platters are paired with magnetic heads, usually arranged on a moving actuator arm, which read and write data to the platter surfaces. Data is accessed in a manner, meaning that individual blocks of data can be stored or retrieved in any order. HDDs are a type of storage, retaining stored data even when powered off. Introduced by IBM in 1956, HDDs became the dominant secondary storage device for computers by the early 1960s. Continuously improved, HDDs have maintained this position into the era of servers. More than 200 companies have produced HDDs historically, though after extensive industry consolidation most current units are manufactured by Seagate, Toshiba, as of 2016, HDD production is growing, although unit shipments and sales revenues are declining. While SSDs have higher cost per bit, SSDs are replacing HDDs where speed, power consumption, small size, the primary characteristics of an HDD are its capacity and performance. Capacity is specified in unit prefixes corresponding to powers of 1000, the two most common form factors for modern HDDs are 3. 5-inch, for desktop computers, and 2. 5-inch, primarily for laptops. HDDs are connected to systems by standard interface cables such as PATA, SATA, Hard disk drives were introduced in 1956, as data storage for an IBM real-time transaction processing computer and were developed for use with general-purpose mainframe and minicomputers. The first IBM drive, the 350 RAMAC in 1956, was approximately the size of two medium-sized refrigerators and stored five million six-bit characters on a stack of 50 disks. In 1962 the IBM350 RAMAC disk storage unit was superseded by the IBM1301 disk storage unit, cylinder-mode read/write operations were supported, and the heads flew about 250 micro-inches above the platter surface. Motion of the head array depended upon a binary system of hydraulic actuators which assured repeatable positioning. The 1301 cabinet was about the size of three home refrigerators placed side by side, storing the equivalent of about 21 million eight-bit bytes, access time was about a quarter of a second. Also in 1962, IBM introduced the model 1311 disk drive, users could buy additional packs and interchange them as needed, much like reels of magnetic tape. Later models of removable pack drives, from IBM and others, became the norm in most computer installations, non-removable HDDs were called fixed disk drives. Some high-performance HDDs were manufactured with one head per track so that no time was lost physically moving the heads to a track, known as fixed-head or head-per-track disk drives they were very expensive and are no longer in production. In 1973, IBM introduced a new type of HDD code-named Winchester and its primary distinguishing feature was that the disk heads were not withdrawn completely from the stack of disk platters when the drive was powered down. Instead, the heads were allowed to land on an area of the disk surface upon spin-down
4.
Floppy disk
–
Floppy disks are read and written by a floppy disk drive. Floppy disks, initially as 8-inch media and later in 5¼-inch and 3½-inch sizes, were a form of data storage and exchange from the mid-1970s into the mid-2000s. These formats are usually handled by older equipment and these disks and associated drives were produced and improved upon by IBM and other companies such as Memorex, Shugart Associates, and Burroughs Corporation. The term floppy disk appeared in print as early as 1970, in 1976, Shugart Associates introduced the first 5¼-inch FDD. By 1978 there were more than 10 manufacturers producing such FDDs, there were competing floppy disk formats, with hard- and soft-sector versions and encoding schemes such as FM, MFM and GCR. The 5¼-inch format displaced the 8-inch one for most applications, the most common capacity of the 5¼-inch format in DOS-based PCs was 360 kB and in 1984 IBM introduced the 1.2 MB dual-sided floppy disk along with its PC-AT model. IBM started using the 720 kB double-density 3½-inch microfloppy disk on its Convertible laptop computer in 1986 and these disk drives could be added to older PC models. In 1988 IBM introduced a drive for 2.88 MB DSED diskettes in its top-of-the-line PS/2 models, throughout the early 1980s, limitations of the 5¼-inch format became clear. Originally designed to be practical than the 8-inch format, it was itself too large, as the quality of recording media grew. A number of solutions were developed, with drives at 2-, 2½-, 3-, 3½-, the large market share of the 5¼-inch format made it difficult for these new formats to gain significant market share. A variant on the Sony design, introduced in 1982 by a number of manufacturers, was then rapidly adopted. By the end of the 1980s, 5¼-inch disks had been superseded by 3½-inch disks, by the mid-1990s, 5¼-inch drives had virtually disappeared, as the 3½-inch disk became the predominant floppy disk. Floppy disks became ubiquitous during the 1980s and 1990s in their use with computers to distribute software, transfer data. Before hard disks became affordable to the population, floppy disks were often used to store a computers operating system. Most home computers from that period have a primary OS and BASIC stored as ROM, by the early 1990s, the increasing software size meant large packages like Windows or Adobe Photoshop required a dozen disks or more. In 1996, there were a five billion standard floppy disks in use. Then, distribution of packages was gradually replaced by CD-ROMs, DVDs. External USB-based floppy disk drives are available, many modern systems provide firmware support for booting from such drives
5.
Molex connector
–
Molex connector is the vernacular term for a two-piece pin and socket interconnection, most frequently disk drive connectors. Pioneered by Molex Connector Company, the design became an early electronic standard. Molex developed and patented the first examples of this style in the late 1950s. First used in appliances, other industries soon began designing it into their products from automobiles to vending machines to mini-computers. In such a connector, cylindrical spring-metal pins fit into cylindrical spring-metal sockets, the pins and sockets are held in a rectangular matrix in a nylon shell. The connector typically has two to 24 contacts and is polarized or keyed to ensure correct orientation, pins and sockets can be arranged in any combination in a single housing, and each housing can be either male or female. There are three typical pin sizes,1.57 mm,2.13 mm, and 2.36 mm, the 1.57 mm pin can carry 5 A of current, while the 2.36 mm can carry 8.5 A. Because the pins have a contact surface area and fit tightly. In October 1963 AMP introduced the MATE-N-LOK connector, the AMP connector was similar to the patented Molex connectors but not interchangeable. Both were widely used in the industry and the term Molex Connector is often improperly used to refer to all nylon plugs. The first 5.25 inch floppy drive, the Shugart SA400. This connector became the standard for 5.25 inch format peripherals such as drives and was used until introduction of SATA drives. In 1983, Molex introduced the 8981 connector that was compatible with the AMP MATE-N-LOK connector. Several connector types have become established for connecting power in desktop PCs, because of the simplicity, reliability, flexibility, and low cost of the Molex design. Certain Molex connectors are used for providing power to the motherboard, fans, floppy drive, CD/DVD drive, video card, some older hard drive models. Compatible connectors are available from manufacturers, not just Molex. Motherboard power connector In 20/24 pin configurations, the Mini-Fit Jr. connector may be used on ATX motherboards as the power connector. 4,6 and 8 pin configurations of the style of connector are used for additional CPU power
6.
Microprocessor
–
A microprocessor is a computer processor which incorporates the functions of a computers central processing unit on a single integrated circuit, or at most a few integrated circuits. Microprocessors contain both combinational logic and sequential digital logic, Microprocessors operate on numbers and symbols represented in the binary numeral system. The integration of a whole CPU onto a chip or on a few chips greatly reduced the cost of processing power. Integrated circuit processors are produced in numbers by highly automated processes resulting in a low per unit cost. Single-chip processors increase reliability as there are many electrical connections to fail. As microprocessor designs get better, the cost of manufacturing a chip generally stays the same, before microprocessors, small computers had been built using racks of circuit boards with many medium- and small-scale integrated circuits. Microprocessors combined this into one or a few large-scale ICs, the internal arrangement of a microprocessor varies depending on the age of the design and the intended purposes of the microprocessor. Advancing technology makes more complex and powerful chips feasible to manufacture, a minimal hypothetical microprocessor might only include an arithmetic logic unit and a control logic section. The ALU performs operations such as addition, subtraction, and operations such as AND or OR, each operation of the ALU sets one or more flags in a status register, which indicate the results of the last operation. The control logic retrieves instruction codes from memory and initiates the sequence of operations required for the ALU to carry out the instruction, a single operation code might affect many individual data paths, registers, and other elements of the processor. As integrated circuit technology advanced, it was feasible to manufacture more and more complex processors on a single chip, the size of data objects became larger, allowing more transistors on a chip allowed word sizes to increase from 4- and 8-bit words up to todays 64-bit words. Additional features were added to the architecture, more on-chip registers sped up programs. Floating-point arithmetic, for example, was not available on 8-bit microprocessors. Integration of the point unit first as a separate integrated circuit and then as part of the same microprocessor chip. Occasionally, physical limitations of integrated circuits made such practices as a bit slice approach necessary, instead of processing all of a long word on one integrated circuit, multiple circuits in parallel processed subsets of each data word. With the ability to put large numbers of transistors on one chip and this CPU cache has the advantage of faster access than off-chip memory, and increases the processing speed of the system for many applications. Processor clock frequency has increased more rapidly than external memory speed, except in the recent past, a microprocessor is a general purpose system. Several specialized processing devices have followed from the technology, A digital signal processor is specialized for signal processing, graphics processing units are processors designed primarily for realtime rendering of 3D images
7.
IBM
–
International Business Machines Corporation is an American multinational technology company headquartered in Armonk, New York, United States, with operations in over 170 countries. The company originated in 1911 as the Computing-Tabulating-Recording Company and was renamed International Business Machines in 1924, IBM manufactures and markets computer hardware, middleware and software, and offers hosting and consulting services in areas ranging from mainframe computers to nanotechnology. IBM is also a research organization, holding the record for most patents generated by a business for 24 consecutive years. IBM has continually shifted its business mix by exiting commoditizing markets and focusing on higher-value, also 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 worlds largest employers, with nearly 380,000 employees. Known as IBMers, IBM employees have been awarded five Nobel Prizes, six Turing Awards, ten National Medals of Technology, in the 1880s, technologies emerged that would ultimately form the core of what would become International Business Machines. 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 1,300 employees and offices and plants in Endicott and Binghamton, New York, Dayton, Ohio, Detroit, Michigan, Washington, D. C. and Toronto. They manufactured machinery for sale and lease, ranging from commercial scales and industrial time recorders, meat 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, Watson joined CTR as General Manager then,11 months later, was made President when court cases relating to his time at NCR were resolved. Having learned Pattersons pioneering business practices, Watson proceeded to put the stamp of NCR onto CTRs companies and his favorite slogan, THINK, became a mantra for each companys employees. During Watsons first four years, revenues more than doubled to $9 million, Watson had never liked the clumsy hyphenated title of the CTR and in 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, in 1937, IBMs tabulating equipment enabled organizations to process unprecedented amounts of data, its clients including the U. S. During the Second World War the company produced small arms for the American war effort, in 1949, Thomas Watson, Sr. created IBM World Trade Corporation, a subsidiary of IBM focused on foreign operations. In 1952, he stepped down after almost 40 years at the company helm, in 1957, the FORTRAN scientific programming language was developed. In 1961, IBM developed the SABRE reservation system for American Airlines, in 1963, IBM employees and computers helped NASA track the orbital flight of the Mercury astronauts. A year later it moved its headquarters from New York City to Armonk. The latter half of the 1960s saw IBM continue its support of space exploration, on April 7,1964, IBM announced the first computer system family, the IBM System/360
8.
Western Digital
–
Western Digital Corporation is an American computer data storage company and one of the largest computer hard disk drive manufacturers in the world, along with Seagate Technology. Western Digital Corporation has a history in the electronics industry as an integrated circuit maker. Western Digital was founded on April 23,1970, by Alvin B, phillips, a Motorola employee, as General Digital, initially a manufacturer of MOS test equipment. It rapidly became a speciality semiconductor maker, with capital provided by several individual investors. Around July 1971, it adopted its current name and soon introduced its first product, the oil crisis of the mid-1970s and the bankruptcy of its biggest calculator customer, Bowmar Instrument, changed its fortunes, however, and in 1976 Western Digital declared Chapter 11 bankruptcy. After this, Emerson withdrew their support of the company, WDC introduced several landmark products during this time, including the MCP-1600 multi-chip, microcoded CPU. The MCP-1600 was used to implement DECs LSI-11 system and their own Pascal MicroEngine microcomputer which ran the UCSD p-System Version III, the processor was also used in several single-chip floppy disk drive controller chips, notably the FD1771. However, the WD integrated circuit that arguably drove Westerns forward integration was the 1771 chip, despite a price far higher than average CMOS chips of the time, it was very successful and extremely profitable. That controller, the WD1003, became the basis of the ATA interface, throughout most of the 1980s, the family of controllers based on the WD1003 provided the bulk of WDCs revenues and profits, and for a time generated enormous corporate growth. Much of the mid-to-late 1980s saw an effort by WDC to use the profits from their ATA storage controllers to become a general-purpose OEM hardware supplier for the PC industry, as a result, WDC purchased a number of hardware companies. These included graphics cards, core logic chipsets, SCSI controller chips for disk and tape devices and they did well, but storage-related chips and disk controllers were their biggest money makers. 1988 also brought what would be the biggest change in WDCs history and that year, WDC bought the hard drive production assets of PC hardware maker Tandon, the first products of that union under WDCs own name were the Centaur series of ATA and XT attachment drives. By 1991, things were starting to slow down, as the PC industry moved from ST-506 and ESDI drives to ATA and SCSI and that year saw the rise of WDCs Caviar drives, brand new designs that used the latest in embedded servo and computerized diagnostic systems. Eventually, the sales of the Caviar drives resulted in WDC starting to sell some of its divisions. Paradise was sold to Philips, and since disappeared and its networking and floppy drive controller divisions went to SMC Networks and its SCSI chip business went to Future Domain, which was later bought out by market leader Adaptec. Around 1995, the lead that the Caviar drives had enjoyed was eclipsed by newer offerings from other companies, especially Quantum Corp. Products and ideas of time did not go far. The Portfolio drive was a flop, as was the SDX hard disk to CD-ROM interface, in an attempt to turn the tide in 1998, WDC recruited the help of IBM
9.
Plug and play
–
Plug and play devices can be due to boot-time assignment of device resources and to hotplug systems such as USB and IEEE1394. In the beginnings of data processing technology, the hardware was just a collection of modules, and this linking was usually done by connecting some wires between modules and disconnecting others. Some early microcomputing devices such as the Apple II sometimes required the end-user to physically cut some wires, the changes were intended to be largely permanent for the life of the hardware. As computers became more accessible to the public, the need developed for more frequent changes to be made by computer users unskilled with using soldering irons. Rather than cutting and soldering connections, configuration was accomplished by jumpers or DIP switches, however, the process of configuring devices manually using jumpers or DIP switches, could be quite difficult, and there was usually no forgiveness for technical inexperience. Incorrect settings could render either the system or just the expansion device completely or partially inoperable. The system might still have seemed to work properly with a setting, until the IRQ or DMA was actually needed. No jumpers or any manual configuration was required, and the independent address space for each slot allowed very cheap & commonplace chips to be used, alongside with cheap glue logic. On the software site, the drivers and extensions were supplied in the cards own ROM, the ROM extensions abstracted any hardware differences and offered standard APIs as specified by ASCII Corporation. In 1984, the NuBus architecture was developed by the Massachusetts Institute of Technology as a platform agnostic peripheral interface that fully automated device configuration, the specification was sufficiently intelligent that it could work with both big endian and little endian computer platforms that had previously been mutually incompatible. However, this agnostic approach increased interfacing complexity and required support chips on every device which in the 1980s was expensive to do, in 1984, Commodore developed the AutoConfig protocol and the Zorro expansion bus for its Amiga line of expandable computers. The first public appearance was in the CES computer show at Las Vegas in 1985, like NuBus, Zorro devices had absolutely no jumpers or DIP switches. The Zorro architecture did not spread to general computing use outside of the Amiga product line, in 1987, IBM released an update to the IBM PC known as the Personal System/2 line of computers using the Micro Channel Architecture. The PS/2 was capable of totally automatic self-configuration, every piece of expansion hardware was issued with a floppy disk containing a special file used to auto-configure the hardware to work with the computer. The user would install the device, turn on the computer, load the configuration information from the disk, and the hardware automatically assigned interrupts, DMA, and so forth. However, the disks posed a problem if they were damaged or lost, without the disks, any new hardware would be completely useless and the computer would not boot at all until the unconfigured device was removed. Microchannel did not gain support, because IBM wanted to exclude clone manufacturers from this next generation computing platform. Anyone developing for MCA had to sign agreements and pay royalties to IBM for each device sold
10.
S-100 bus
–
The S-100 bus or Altair bus, IEEE696-1983, was an early computer bus designed in 1974 as a part of the Altair 8800. The S-100 bus was the first industry standard bus for the microcomputer industry. S-100 computers, consisting of processor and peripheral cards, were produced by a number of manufacturers, the S-100 bus formed the basis for homebrew computers whose builders implemented drivers for CP/M and MP/M. These S-100 microcomputers ran the gamut from hobbyist toy to small business workstation and were common in home computers until the advent of the IBM PC. The S-100 bus is a passive backplane of 100-pin printed circuit board edge connectors wired in parallel, circuit cards measuring 5 × 10-inches serving the functions of CPU, memory, or I/O interface plugged into these connectors. The bus signal definitions closely follow those of an 8080 microprocessor system, the 100 lines of the S-100 bus can be grouped into four types, 1) Power, 2) Data, 3) Address, and 4) Clock and control. Power supplied on the bus was unregulated +8 V and ±16 V, designed to be regulated on the cards to +5 V, the onboard voltage regulation was typically performed by devices of the 78xx family. These were linear regulators which commonly were mounted on heat sinks, the bi-directional 8-bit data bus of the Intel 8080 was split into two unidirectional 8-bit data buses. Later these two 8-bit busses would be combined to support a 16-bit data width for more advanced processors, the address bus was 16-bits wide in the initial implementation and later extended to 24-bits wide. A bus control signal could put these lines in a condition to allow direct memory access. The Cromemco Dazzler, for example, was an early S-100 card that retrieved digital images from memory using direct memory access, Clock and control signals were used to manage the traffic on the bus. For example the DO Disable line would tristate the address lines during direct memory access, unassigned lines of the original bus specification were later assigned to support more advanced processors. For example, the Zilog Z-80 processor had an interrupt line that the Intel 8080 processor did not. One unassigned line of the S-100 bus then was reassigned to support the non-maskable interrupt request, during the design of the Altair, the hardware required to make a usable machine was not available in time for the January 1975 launch date. The designer, Ed Roberts, also had the problem of the taking up too much room. Attempting to avoid problems, he placed the existing components in a case with additional slots. The backplane was split into four separate cards, with the CPU on a fifth and he then looked for an inexpensive source of connectors, and he came across a supply of military surplus 100-pin edge connectors. The 100-pin bus was created by a draftsman, who selected the connector from a parts catalog
.jpg)
Category