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BIOS Interrupt Call
BIOS implementations provide interrupts that can be invoked by operating systems and application programs to use the facilities of the firmware on IBM PC compatible computers. Traditionally, BIOS calls are mainly used by DOS programs and some other software such as boot loaders (including, mostly historically, relatively simple application software that boots directly and runs without an operating system—especially game software). BIOS runs in the real address mode (Real Mode) of the x86 CPU, so programs that call BIOS either must also run in real mode or must switch from protected mode to real mode before calling BIOS and then switching back again. For this reason, modern operating systems that use the CPU in Protected mode or Long mode generally do not use the BIOS interrupt calls to support system functions, although they use the BIOS interrupt calls to probe and initialize hardware during booting. Real mode has the 1MB memory limitation, modern boot loaders (e.g. GRUB ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BIOS
In computing, BIOS (, ; Basic Input/Output System, also known as the System BIOS, ROM BIOS, BIOS ROM or PC BIOS) is a type of firmware used to provide runtime services for operating systems and programs and to perform hardware initialization during the booting process (power-on startup). The firmware comes pre-installed on the computer's motherboard. The name originates from the Basic Input/Output System used in the CP/M operating system in 1975. The BIOS firmware was originally proprietary to the IBM PC; it was reverse engineered by some companies (such as Phoenix Technologies) looking to create compatible systems. The interface of that original system serves as a ''de facto'' standard. The BIOS in older PCs initializes and tests the system hardware components ( power-on self-test or POST for short), and loads a boot loader from a mass storage device which then initializes a kernel. In the era of DOS, the BIOS provided BIOS interrupt calls for the keyboard, display, st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM Personal Computer/AT
The IBM Personal Computer AT (model 5170, abbreviated as IBM AT or PC/AT) was released in 1984 as the fourth model in the IBM Personal Computer line, following the IBM PC/XT and its IBM Portable PC variant. It was designed around the Intel 80286 microprocessor. Name IBM did not specify an expanded form of ''AT'' on the machine, press releases, brochures or documentation, but some sources expand the term as ''Advanced Technology'', including at least one internal IBM document. History IBM's 1984 introduction of the AT was seen as an unusual move for the company, which typically waited for competitors to release new products before producing its own models. At $4,000–6,000, it was only slightly more expensive than considerably slower IBM models. The announcement surprised rival executives, who admitted that matching IBM's prices would be difficult. No major competitor showed a comparable computer at COMDEX Las Vegas that year. Features The AT is IBM PC compatible, wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interrupt Vector Table
An interrupt vector table (IVT) is a data structure that associates a list of interrupt handlers with a list of interrupt requests in a table of interrupt vectors. Each entry of the interrupt vector table, called an interrupt vector, is the address of an interrupt handler (also known as Interrupt_handler, ISR). While the concept is common across processor architectures, IVTs may be implemented in architecture-specific fashions. For example, a dispatch table is one method of implementing an interrupt vector table. Background Most processors have an interrupt vector table, including chips from Intel, AMD, Infineon Technologies, Infineon, Microchip AVR microcontrollers, Atmel, NXP, ARM architecture, ARM, etc. Interrupt handlers Handling methods An interrupt vector table is used in the three most popular methods of finding the starting address of the interrupt service routine: "Predefined" The "predefined" method loads the program counter (PC) directly with the address of some ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Terminal
A computer terminal is an electronic or electromechanical hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system. Most early computers only had a front panel to input or display bits and had to be connected to a terminal to print or input text through a keyboard. Teleprinters were used as early-day hard-copy terminals and predated the use of a computer screen by decades. The computer would typically transmit a line of data which would be printed on paper, and accept a line of data from a keyboard over a serial or other interface. Starting in the mid-1970s with microcomputers such as the Sphere 1, Sol-20, and Apple I, display circuitry and keyboards began to be integrated into personal and workstation computer systems, with the computer handling character generation and outputting to a CRT display such as a computer monitor or, sometimes, a consumer TV, but most larger computers continued to require terminal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM Personal Computer XT
The IBM Personal Computer XT (model 5160, often shortened to PC/XT) is the second computer in the IBM Personal Computer line, released on March 8, 1983. Except for the addition of a built-in Hard disk drive, hard drive and extra expansion slots, it is very similar to the original IBM PC model 5150 from 1981. Name IBM did not specify an expanded form of "XT" on the machine, press releases, brochures or documentation, but some publications expanded the term as "''eXtended Technology''" or just "''eXTended''". Features The XT was regarded as an incremental improvement over the PC and a disappointment compared to the next-generation successor that some had anticipated. Compared to the original IBM PC, the XT has the following major differences: * The number of expansion slots was increased from five to eight * Base RAM was increased to at least 128 KB * 2x32KB ROM ICs replace the previous 5x8KB ROM ICs * A 10 MB hard drive was included on most sub-models, with a disk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM Personal Computer
The IBM Personal Computer (model 5150, commonly known as the IBM PC) is the first microcomputer released in the IBM PC model line and the basis for the IBM PC compatible ''de facto'' standard. Released on August 12, 1981, it was created by a team of engineers and designers at International Business Machines (IBM), directed by William C. Lowe and Philip Don Estridge in Boca Raton, Florida. Powered by an x86-architecture Intel 8088 processor, the machine was based on open architecture and third-party peripherals. Over time, expansion cards and software technology increased to support it. The PC had a substantial influence on the personal computer market; the specifications of the IBM PC became one of the most popular computer design standards in the world. The only significant competition it faced from a non-compatible platform throughout the 1980s was from Apple's Macintosh product line, as well as consumer-grade platforms created by companies like Commodore and Atari. Mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM PCjr
The IBM PCjr (pronounced "PC junior") was a home computer produced and marketed by IBM from March 1984 to May 1985, intended as a lower-cost variant of the IBM PC with hardware capabilities better suited for video games, in order to compete more directly with other home computers such as the Apple II and Commodore 64. It retained the IBM PC's Intel 8088, 8088 CPU and BIOS interface, but provided enhanced graphics and sound, ROM cartridge slots, built-in joystick ports, and an infrared wireless keyboard. The PCjr supported expansion via "sidecar" modules, which could be attached to the side of the unit. Despite widespread anticipation, the PCjr was ultimately unsuccessful in the market. It was only partially IBM PC compatible, limiting support for IBM's software library. Its chiclet keyboard was widely criticized for its poor quality. The PCjr also suffered from limited expandability; it was initially offered with a maximum of of RAM, insufficient for many PC programs. Models ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western Digital
Western Digital Corporation is an American data storage company headquartered in San Jose, California. Established in 1970, the company is one of the world's largest manufacturers of hard disk drives (HDDs). History 1970s Western Digital was founded on April 23, 1970, by Alvin B. Phillips, a Motorola employee, as General Digital Corporation, initially a manufacturer of MOS test equipment. It was originally based in Newport Beach, California, shortly thereafter moving to Santa Ana, California, and would go on to become one of the largest technology firms headquartered in Orange County. It rapidly became a specialty semiconductor maker, with start-up capital provided by several individual investors and industrial giant Emerson Electric. Around July 1971, it adopted its current name and soon introduced its first product, the ''WD1402A'' UART. During the early 1970s, the company focused on making and selling calculator chips, and by 1975, Western Digital was the largest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ST-506
The ST-506 and ST-412 (sometimes written ST506 and ST412) were early hard disk drive products introduced by Seagate in 1980 and 1981 respectively, that later became construed as hard disk drive interfaces: the ST-506 disk interface and the ST-412 disk interface. Introduced in 1980, the ST-506 was the first 5.25 inch HDD. Its successor, the ST-412, was introduced in 1981 and implemented a refinement to the seek speed, and increased the drive capacity from 5 MB to 10 MB, but was otherwise highly similar. Beginning with its selection as the hard drive subsystem for the original IBM XT disk drive controllers supporting the ST-412 interface grew to become ubiquitous in the personal computer industry, The ST-412 interface and its variants were the de facto industry standard for personal computer hard disks until the advent and wider adoption of the IDE or ATA interface in the early 1990s. Both interfaces used MFM encoding; the subsequent extension of the ST-412 interface, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Run Length Limited
Run-length limited (RLL) is a line coding technique that is used to send arbitrary data over a communications channel with bandwidth limits. RLL codes are defined by four main parameters: ''m'', ''n'', ''d'', ''k''. The first two, ''m''/''n'', refer to the rate of the code, while the remaining two specify the minimal ''d'' and maximal ''k'' number of zeroes between consecutive ones. This is used in both telecommunication and storage systems that move a medium past a fixed recording head. Specifically, RLL bounds the length of stretches (runs) of repeated bits during which the signal does not change. If the runs are too long, clock recovery is difficult; if they are too short, the high frequencies might be attenuated by the communications channel. By modulating the data, RLL reduces the timing uncertainty in decoding the stored data, which would lead to the possible erroneous insertion or removal of bits when reading the data back. This mechanism ensures that the boundaries bet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enhanced Small Disk Interface
Enhanced Small Disk Interface (ESDI) is a hard disk drive interface designed by Maxtor Corporation in 1983 to be a follow-on to the ST-412/506 interface. ESDI improved on ST-506 by moving certain parts that were traditionally kept on the controller (such as the data separator) into the drives themselves, and also generalizing the control bus such that more kinds of devices (such as removable disks and tape drives) could be connected. ESDI uses the same cabling as ST-506 (one 34-pin common control cable, and a 20-pin data channel cable for each device), and thus could easily be retrofitted to ST-506 applications. ESDI was popular in the mid-to-late 1980s, when SCSI and IDE technologies were young and immature, and ST-506 was neither fast nor flexible enough. ESDI could handle data rates of 10, 15, or 20 Mbit/s (as opposed to ST-506's top speed of 7.5 Mbit/s), and many high-end SCSI drives of the era were actually high-end ESDI drives with SCSI bridge A bridge is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
