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70-488: The ESCD data may at one time have been stored in the latter portion of the 128 byte extended bank of battery-backed CMOS RAM but eventually it became too large and so was moved to BIOS flash. It contains information about ISA PnP devices is stored. It is used by the BIOS to allocate resources for devices like expansion cards . The ESCD data is stored using the data serialization format used for EISA . Its data starts with

140-615: A water cooling system instead of many fans. Some small form factor computers and home theater PCs designed for quiet and energy-efficient operation boast fan-less designs. This typically requires the use of a low-power CPU, as well as a careful layout of the motherboard and other components to allow for heat sink placement. A 2003 study found that some spurious computer crashes and general reliability issues, ranging from screen image distortions to I/O read/write errors, can be attributed not to software or peripheral hardware but to aging capacitors on PC motherboards. Ultimately this

210-724: A 16-bit transfer size, signal timing in the PIO modes and the interrupt and DMA mechanisms. The PC/XT-bus is an eight- bit ISA bus used by Intel 8086 and Intel 8088 systems in the IBM PC and IBM PC XT in the 1980s. Among its 62 pins were demultiplexed and electrically buffered versions of the 8 data and 20 address lines of the 8088 processor, along with power lines, clocks, read/write strobes, interrupt lines, etc. Power lines included −5 V and ±12 V in order to directly support pMOS and enhancement mode nMOS circuits such as dynamic RAMs among other things. The XT bus architecture uses

280-781: A buffered interface to the motherboard buses of the Intel 8088 (16/8 bit) CPU in the IBM PC and PC/XT, augmented with prioritized interrupts and DMA channels. The 16-bit version was an upgrade for the motherboard buses of the Intel 80286 CPU (and expanded interrupt and DMA facilities) used in the IBM AT, with improved support for bus mastering. The ISA bus was therefore synchronous with the CPU clock until sophisticated buffering methods were implemented by chipsets to interface ISA to much faster CPUs. ISA

350-439: A card-cage case with components connected by a backplane containing a set of interconnected sockets into which the circuit boards are plugged. In very old designs, copper wires were the discrete connections between card connector pins, but printed circuit boards soon became the standard practice. The central processing unit (CPU), memory, and peripherals were housed on individually printed circuit boards, which were plugged into

420-483: A combination of modifications to hardware, the system BIOS , and operating system software to automatically manage resource allocations. In reality, ISA PnP could be troublesome and did not become well-supported until the architecture was in its final days. A PnP ISA, EISA or VLB device may have a 5-byte EISA ID (3-byte manufacturer ID + 2-byte hex number) to identify the device. For example, CTL0044 corresponds to Creative Sound Blaster 16 / 32 PnP . PCI slots were

490-406: A different number of connections depending on its standard and form factor . A standard, modern ATX motherboard will typically have two or three PCI-Express x16 connection for a graphics card, one or two legacy PCI slots for various expansion cards, and one or two PCI-E x1 (which has superseded PCI ). A standard EATX motherboard will have two to four PCI-E x16 connection for graphics cards, and

560-524: A few unique signal lines specific to ATA/IDE hard disks (such as the Cable Select/Spindle Sync. line.) In addition to the physical interface channel, ATA goes beyond and far outside the scope of ISA by also specifying a set of physical device registers to be implemented on every ATA (IDE) drive and a full set of protocols and device commands for controlling fixed disk drives using these registers. The ATA device registers are accessed using

630-423: A lifetime of 3 to 4 years can be expected. However, many manufacturers deliver substandard capacitors, which significantly reduce life expectancy. Inadequate case cooling and elevated temperatures around the CPU socket exacerbate this problem. With top blowers, the motherboard components can be kept under 95 °C (203 °F), effectively doubling the motherboard lifetime. Mid-range and high-end motherboards, on

700-555: A peripheral device. If no peripheral device containing an operating system was available, then the computer would perform tasks from other ROM stores or display an error message, depending on the model and design of the computer. For example, both the Apple II and the original IBM PC had Cassette BASIC (ROM BASIC) and would start that if no operating system could be loaded from the floppy disk or hard disk. The boot firmware in modern IBM PC compatible motherboard designs contains either

770-453: A second 8259 PIC (connected to one of the lines of the first) and 4 × 16-bit DMA channels, as well as control lines to select 8- or 16-bit transfers. The 16-bit AT bus slot originally used two standard edge connector sockets in early IBM PC/AT machines. However, with the popularity of the AT architecture and the 16-bit ISA bus, manufacturers introduced specialized 98-pin connectors that integrated

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840-529: A separate clock generator, or a clock divider which either fixed the ISA bus frequency at 4, 6, or 8 MHz or allowed the user to adjust the frequency via the BIOS setup. When used at a higher bus frequency, some ISA cards (certain Hercules-compatible video cards, for instance), could show significant performance improvements. Memory address decoding for the selection of 8 or 16-bit transfer mode

910-448: A separate component. Business PCs, workstations, and servers were more likely to need expansion cards, either for more robust functions, or for higher speeds; those systems often had fewer embedded components. Laptop and notebook computers that were developed in the 1990s integrated the most common peripherals. This even included motherboards with no upgradeable components, a trend that would continue as smaller systems were introduced after

980-412: A set of low-speed peripherals: PS/2 keyboard and mouse , floppy disk drive , serial ports , and parallel ports . By the late 1990s, many personal computer motherboards included consumer-grade embedded audio, video, storage, and networking functions without the need for any expansion cards at all; higher-end systems for 3D gaming and computer graphics typically retained only the graphics card as

1050-551: A single Intel 8259 PIC , giving eight vectorized and prioritized interrupt lines. It has four DMA channels originally provided by the Intel 8237 . Three of the DMA channels are brought out to the XT bus expansion slots; of these, 2 are normally already allocated to machine functions (diskette drive and hard disk controller): The PC/AT-bus , a 16- bit (or 80286-) version of the PC/XT bus,

1120-433: A variety of other custom components. Similarly, the term mainboard describes a device with a single board and no additional expansions or capability, such as controlling boards in laser printers, television sets, washing machines, mobile phones, and other embedded systems with limited expansion abilities. Prior to the invention of the microprocessor , the CPU of a digital computer consisted of multiple circuit boards in

1190-704: A variety of sizes and shapes called form factors , some of which are specific to individual computer manufacturers. However, the motherboards used in IBM-compatible systems are designed to fit various case sizes. As of 2024 , most desktop computer motherboards use the ATX standard form factor — even those found in Macintosh and Sun computers, which have not been built from commodity components. A case's motherboard and power supply unit (PSU) form factor must all match, though some smaller form factor motherboards of

1260-515: A varying number of PCI and PCI-E x1 slots. It can sometimes also have a PCI-E x4 slot (will vary between brands and models). Some motherboards have two or more PCI-E x16 slots, to allow more than 2 monitors without special hardware, or use a special graphics technology called SLI (for Nvidia ) and Crossfire (for AMD ). These allow 2 to 4 graphics cards to be linked together, to allow better performance in intensive graphical computing tasks, such as gaming, video editing, etc. In newer motherboards,

1330-402: Is a derivative of the ISA bus, utilizing the same signal lines with different connectors. The LPC bus has replaced the ISA bus as the connection to the legacy I/O devices on current motherboards; while physically quite different, LPC looks just like ISA to software, so the peculiarities of ISA such as the 16 MiB DMA limit (which corresponds to the full address space of the Intel 80286 CPU used in

1400-653: Is directly descended from the 16-bit ISA of the PC/AT. ATA has its origins in the IBM Personal Computer Fixed Disk and Diskette Adapter, the standard dual-function floppy disk controller and hard disk controller card for the IBM PC AT; the fixed disk controller on this card implemented the register set and the basic command set which became the basis of the ATA interface (and which differed greatly from

1470-530: Is equipped with two ISA slots. It was marketed to industrial and military users who had invested in expensive specialized ISA bus adaptors, which were not available in PCI bus versions. Similarly, ADEK Industrial Computers released a modern motherboard in early 2013 for Intel Core i3/i5/i7 processors, which contains one (non-DMA) ISA slot. Also, MSI released a modern motherboard with one ISA slot in 2020. The PC/104 bus, used in industrial and embedded applications,

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1540-414: Is now fairly hard to find. Some XT-IDE adapters were available as 8-bit ISA cards, and XTA sockets were also present on the motherboards of Amstrad 's later XT clones as well as a short-lived line of Philips units. The XTA pinout was very similar to ATA, but only eight data lines and two address lines were used, and the physical device registers had completely different meanings. A few hard drives (such as

1610-415: Is the main printed circuit board (PCB) in general-purpose computers and other expandable systems. It holds and allows communication between many of the crucial electronic components of a system, such as the central processing unit (CPU) and memory , and provides connectors for other peripherals . Unlike a backplane , a motherboard usually contains significant sub-systems, such as the central processor,

1680-406: Is usually more expensive than a desktop motherboard. A CPU socket (central processing unit) or slot is an electrical component that attaches to a printed circuit board (PCB) and is designed to house a CPU (also called a microprocessor). It is a special type of integrated circuit socket designed for very high pin counts. A CPU socket provides many functions, including a physical structure to support

1750-555: The 8-bit bus of the 8088 -based IBM PC , including the IBM PC/XT as well as IBM PC compatibles . Originally referred to as the PC bus (8-bit) or AT bus (16-bit), it was also termed I/O Channel by IBM. The ISA term was coined as a retronym by IBM PC clone manufacturers in the late 1980s or early 1990s as a reaction to IBM attempts to replace the AT bus with its new and incompatible Micro Channel architecture . The 16-bit ISA bus

1820-704: The Apple II and IBM PC include only this minimal peripheral support on the motherboard. Occasionally video interface hardware was also integrated into the motherboard; for example, on the Apple II and rarely on IBM-compatible computers such as the IBM PCjr . Additional peripherals such as disk controllers and serial ports were provided as expansion cards. Given the high thermal design power of high-speed computer CPUs and components, modern motherboards nearly always include heat sinks and mounting points for fans to dissipate excess heat. Motherboards are produced in

1890-477: The Apple II and IBM PC used ROM chips mounted in sockets on the motherboard. At power-up, the central processor unit would load its program counter with the address of the Boot ROM and start executing instructions from the Boot ROM. These instructions initialized and tested the system hardware, displayed system information on the screen, performed RAM checks, and then attempts to boot an operating system from

1960-429: The M.2 slots are for SSD and/or wireless network interface controller . Motherboards are generally air cooled with heat sinks often mounted on larger chips in modern motherboards. Insufficient or improper cooling can cause damage to the internal components of the computer, or cause it to crash . Passive cooling , or a single fan mounted on the power supply , was sufficient for many desktop computer CPU's until

2030-515: The PC/104 bus, and internally within Super I/O chips. Even though ISA disappeared from consumer desktops many years ago, it is still used in industrial PCs , where certain specialized expansion cards that never transitioned to PCI and PCI Express are used. The original PC bus was developed by a team led by Mark Dean at IBM as part of the IBM PC project in 1981. It was an 8-bit bus based on

2100-467: The Seagate ST351A/X) could support either type of interface, selected with a jumper. Many later AT (and AT successor) motherboards had no integrated hard drive interface but relied on a separate hard drive interface plugged into an ISA/EISA/VLB slot. There were even a few 80486-based units shipped with MFM/RLL interfaces and drives instead of the increasingly common AT-IDE. Commodore built

2170-482: The chipset 's input/output and memory controllers, interface connectors, and other components integrated for general use. Motherboard means specifically a PCB with expansion capabilities. As the name suggests, this board is often referred to as the mother of all components attached to it, which often include peripherals, interface cards, and daughterboards : sound cards , video cards , network cards , host bus adapters , TV tuner cards , IEEE 1394 cards, and

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2240-434: The floppy drive , serial ports , etc., which was why the software compatible LPC bus was created. ISA slots remained for a few more years, and towards the turn of the century it was common to see systems with an Accelerated Graphics Port (AGP) sitting near the central processing unit , an array of PCI slots, and one or two ISA slots near the end. In late 2008, even floppy disk drives and serial ports were disappearing, and

2310-559: The "ACFG" signature in ASCII. PCI configuration can also be stored in ESCD, using virtual slots. Typical storage usage for ESCD data is 2–4 KB The BIOS also updates the ESCD each time the hardware configuration changes, after deciding how to re-allocate resources like IRQ and memory mapping ranges. After the ESCD has been updated, the decision need not be made again, which thereafter results in faster startup without conflicts until

2380-408: The "Gang of Nine" group of PC-compatible manufacturers that included Compaq. Compaq created the term Industry Standard Architecture (ISA) to replace PC compatible . In the process, they retroactively renamed the AT bus to ISA to avoid infringing IBM's trademark on its PC and PC/AT systems (and to avoid giving their major competitor, IBM, free advertisement). IBM designed the 8-bit version as

2450-401: The 16-bit bus. ISA was also used in some non-IBM compatible machines such as Motorola 68k -based Apollo (68020) and Amiga 3000 (68030) workstations, the short-lived AT&T Hobbit and the later PowerPC -based BeBox . Companies like Dell improved the AT bus's performance but in 1987, IBM replaced the AT bus with its proprietary Micro Channel Architecture (MCA). MCA overcame many of

2520-402: The ATA standard (up to 133 MB/s for ATA-6, the latest.) In most forms, ATA ran much faster than ISA, provided it was connected directly to a local bus (e.g. southbridge-integrated IDE interfaces) faster than the ISA bus. Before the 16-bit ATA/IDE interface, there was an 8-bit XT-IDE (also known as XTA) interface for hard disks. It was not nearly as popular as ATA has become, and XT-IDE hardware

2590-420: The CPU series and speed. With the steadily declining costs and size of integrated circuits , it is now possible to include support for many peripherals on the motherboard. By combining many functions on one PCB , the physical size and total cost of the system may be reduced; highly integrated motherboards are thus especially popular in small form factor and budget computers. A typical motherboard will have

2660-471: The CPU, support for a heat sink, facilitating replacement (as well as reducing cost), and most importantly, forming an electrical interface both with the CPU and the PCB. CPU sockets on the motherboard can most often be found in most desktop and server computers (laptops typically use surface mount CPUs), particularly those based on the Intel x86 architecture. A CPU socket type and motherboard chipset must support

2730-695: The I/O bus of the IBM System/23 Datamaster system - it used the same physical connector, and a similar signal protocol and pinout. A 16-bit version, the IBM AT bus, was introduced with the release of the IBM PC/AT in 1984. The AT bus was a mostly backward-compatible extension of the PC bus—the AT bus connector was a superset of the PC bus connector. In 1988, the 32-bit EISA standard was proposed by

2800-624: The P996 specification. However, despite books being published on the P996 specification, it never officially progressed past draft status. There still is an existing user base with old computers, so some ISA cards are still manufactured, e.g. with USB ports or complete single-board computers based on modern processors, USB 3.0 , and SATA . Motherboard A motherboard (also called mainboard , main circuit board , MB , base board , system board , or, in Apple computers, logic board )

2870-477: The PCMCIA interface is much more complex than ATA. Although most modern computers do not have physical ISA buses, almost all PCs — IA-32 , and x86-64 — have ISA buses allocated in physical address space. Some Southbridges and some CPUs themselves provide services such as temperature monitoring and voltage readings through ISA buses as ISA devices. IEEE started a standardization of the ISA bus in 1985, called

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2940-578: The XT-IDE-based peripheral hard drive and memory expansion unit A590 for their Amiga 500 and 500+ computers that also supported a SCSI drive. Later models – the A600 , A1200 , and the Amiga 4000 series – use AT-IDE drives. The PCMCIA specification can be seen as a superset of ATA. The standard for PCMCIA hard disk interfaces, which included PCMCIA flash drives, allows for the mutual configuration of

3010-734: The address bits and address select signals in the ATA physical interface channel, and all operations of ATA hard disks are performed using the ATA-specified protocols through the ATA command set. The earliest versions of the ATA standard featured a few simple protocols and a basic command set comparable to the command sets of MFM and RLL controllers (which preceded ATA controllers), but the latest ATA standards have much more complex protocols and instruction sets that include optional commands and protocols providing such advanced optional-use features as sizable hidden system storage areas, password security locking, and programmable geometry translation. In

3080-574: The backplane. In older microprocessor-based systems, the CPU and some support circuitry would fit on a single CPU board, with memory and peripherals on additional boards, all plugged into the backplane. The ubiquitous S-100 bus of the 1970s is an example of this type of backplane system. The most popular computers of the 1980s such as the Apple II and IBM PC had published schematic diagrams and other documentation which permitted rapid reverse engineering and third-party replacement motherboards. Usually intended for building new computers compatible with

3150-574: The drive and controller to a drive bay and used a ribbon cable and a very simple interface board to connect it to an ISA slot. ATA is basically a standardization of this arrangement plus a uniform command structure for software to interface with the HDC within the drive. ATA has since been separated from the ISA bus and connected directly to the local bus, usually by integration into the chipset, for much higher clock rates and data throughput than ISA could support. ATA has clear characteristics of 16-bit ISA, such as

3220-414: The exemplars, many motherboards offered additional performance or other features and were used to upgrade the manufacturer's original equipment. During the late 1980s and early 1990s, it became economical to move an increasing number of peripheral functions onto the motherboard. In the late 1980s, personal computer motherboards began to include single ICs (also called Super I/O chips) capable of supporting

3290-479: The extinction of vestigial ISA (by then the LPC bus) from chipsets was on the horizon. PCI slots are rotated compared to their ISA counterparts—PCI cards were essentially inserted upside-down, allowing ISA and PCI connectors to squeeze together on the motherboard. Only one of the two connectors can be used in each slot at a time, but this allowed for greater flexibility. The AT Attachment (ATA) hard disk interface

3360-474: The first physically incompatible expansion ports to directly squeeze ISA off the motherboard. At first, motherboards were largely ISA, including a few PCI slots. By the mid-1990s, the two slot types were roughly balanced, and ISA slots soon were in the minority of consumer systems. Microsoft 's PC-99 specification recommended that ISA slots be removed entirely, though the system architecture still required ISA to be present in some vestigial way internally to handle

3430-476: The interface of IBM's fixed disk controller card for the PC XT). Direct precursors to ATA were third-party ISA hardcards that integrated a hard disk drive (HDD) and a hard disk controller (HDC) onto one card. This was at best awkward and at worst damaging to the motherboard, as ISA slots were not designed to support such heavy devices as HDDs. The next generation of Integrated Drive Electronics drives moved both

3500-410: The late 1990s; since then, most have required CPU fans mounted on heat sinks , due to rising clock speeds and power consumption. Most motherboards have connectors for additional computer fans and integrated temperature sensors to detect motherboard and CPU temperatures and controllable fan connectors which the BIOS or operating system can use to regulate fan speed. Alternatively computers can use

3570-419: The later VESA Local Bus (VLB). VLB used some electronic parts originally intended for MCA because component manufacturers already were equipped to manufacture them. Both EISA and VLB were backward-compatible expansions of the AT (ISA) bus. Users of ISA-based machines had to know special information about the hardware they were adding to the system. While a handful of devices were essentially plug-n-play , this

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3640-588: The limitations then apparent in ISA but was also an effort by IBM to regain control of the PC architecture and the PC market. MCA was far more advanced than ISA and had many features that would later appear in PCI. However, MCA was also a closed standard whereas IBM had released full specifications and circuit schematics for ISA. Computer manufacturers responded to MCA by developing the Extended Industry Standard Architecture (EISA) and

3710-449: The mid-1990s, the ATA host controller (usually integrated into the chipset) was moved to PCI form. A further deviation between ISA and ATA is that while the ISA bus remained locked into a single standard clock rate (for backward hardware compatibility), the ATA interface offered many different speed modes, could select among them to match the maximum speed supported by the attached drives, and kept adding faster speeds with later versions of

3780-433: The motherboard cooling and monitoring solutions are usually based on a super I/O chip or an embedded controller . Motherboards contain a ROM (and later EPROM , EEPROM , NOR flash ) that stores firmware that initializes hardware devices and boots an operating system from a peripheral device . The terms bootstrapping and boot come from the phrase "lifting yourself by your bootstraps". Microcomputers such as

3850-419: The motherboard. Other components such as external storage , controllers for video display and sound , and peripheral devices may be attached to the motherboard as plug-in cards or via cables; in modern microcomputers, it is increasingly common to integrate some of these peripherals into the motherboard itself. An important component of a motherboard is the microprocessor's supporting chipset , which provides

3920-410: The next hardware configuration change. This computer hardware article is a stub . You can help Misplaced Pages by expanding it . Industry Standard Architecture Industry Standard Architecture ( ISA ) is the 16-bit internal bus of IBM PC/AT and similar computers based on the Intel 80286 and its immediate successors during the 1980s. The bus was (largely) backward compatible with

3990-583: The original IBM AT) are likely to stick around for a while. As explained in the History section, ISA was the basis for development of the ATA interface, used for ATA (a.k.a. IDE) hard disks. Physically, ATA is essentially a simple subset of ISA, with 16 data bits, support for exactly one IRQ and one DMA channel, and 3 address bits. To this ISA subset, ATA adds two IDE address select ("chip select") lines (i.e. address decodes, effectively equivalent to address bits) and

4060-443: The other hand, use solid capacitors exclusively. For every 10 °C less, their average lifespan is multiplied approximately by three, resulting in a 6-times higher lifetime expectancy at 65 °C (149 °F). These capacitors may be rated for 5000, 10000 or 12000 hours of operation at 105 °C (221 °F), extending the projected lifetime in comparison with standard solid capacitors. In desktop PCs and notebook computers,

4130-496: The port and the drive in an ATA mode. As a de facto extension, most PCMCIA flash drives additionally allow for a simple ATA mode that is enabled by pulling a single pin low, so that PCMCIA hardware and firmware are unnecessary to use them as an ATA drive connected to an ATA port. PCMCIA flash drive to ATA adapters are thus simple and inexpensive but are not guaranteed to work with any and every standard PCMCIA flash drive. Further, such adapters cannot be used as generic PCMCIA ports, as

4200-406: The same family will fit larger cases. For example, an ATX case will usually accommodate a microATX motherboard. Laptop computers generally use highly integrated, miniaturized, and customized motherboards. This is one of the reasons that laptop computers are difficult to upgrade and expensive to repair. Often the failure of one laptop component requires the replacement of the entire motherboard, which

4270-487: The same time, up to 4 devices may use one 8-bit DMA channel each, while up to 3 devices can use one 16-bit DMA channel each. Originally, the bus clock was synchronous with the CPU clock, resulting in varying bus clock frequencies among the many different IBM clones on the market (sometimes as high as 16 or 20 MHz), leading to software or electrical timing problems for certain ISA cards at bus speeds they were not designed for. Later motherboards or integrated chipsets used

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4340-405: The supporting interfaces between the CPU and the various buses and external components. This chipset determines, to an extent, the features and capabilities of the motherboard. Modern motherboards include: Additionally, nearly all motherboards include logic and connectors to support commonly used input devices, such as USB for mouse devices and keyboards . Early personal computers such as

4410-507: The turn of the century (like the tablet computer and the netbook ). Memory, processors, network controllers, power source, and storage would be integrated into some systems. A motherboard provides the electrical connections by which the other components of the system communicate. Unlike a backplane, it also contains the central processing unit and hosts other subsystems and devices. A typical desktop computer has its microprocessor , main memory , and other essential components connected to

4480-490: The two sockets into one unit. These can be found in almost every AT-class PC manufactured after the mid-1980s. The ISA slot connector is typically black (distinguishing it from the brown EISA connectors and white PCI connectors). Motherboard devices have dedicated IRQs (not present in the slots). 16-bit devices can use either PC-bus or PC/AT-bus IRQs. It is therefore possible to connect up to 6 devices that use one 8-bit IRQ each and up to 5 devices that use one 16-bit IRQ each. At

4550-519: Was also used with 32-bit processors for several years. An attempt to extend it to 32 bits, called Extended Industry Standard Architecture (EISA), was not very successful, however. Later buses such as VESA Local Bus and PCI were used instead, often along with ISA slots on the same mainboard . Derivatives of the AT bus structure were and still are used in ATA/IDE , the PCMCIA standard, CompactFlash ,

4620-425: Was designed to connect peripheral cards to the motherboard and allows for bus mastering . Only the first 16 MB of main memory is addressable. The original 8-bit bus ran from the 4.77 MHz clock of the 8088 CPU in the IBM PC and PC/XT. The original 16-bit bus ran from the CPU clock of the 80286 in IBM PC/AT computers, which was 6 MHz in the first models and 8 MHz in later models. The IBM RT PC also used

4690-545: Was introduced with the IBM PC/AT . This bus was officially termed I/O Channel by IBM. It extends the XT-bus by adding a second shorter edge connector in-line with the eight-bit XT-bus connector, which is unchanged, retaining compatibility with most 8-bit cards. The second connector adds four additional address lines for a total of 24, and 8 additional data lines for a total of 16. It also adds new interrupt lines connected to

4760-494: Was limited to 128 KiB sections, leading to problems when mixing 8- and 16-bit cards as they could not co-exist in the same 128 KiB area. This is because the MEMCS16 line is required to be set based on the value of LA17-23 only. ISA is still used today for specialized industrial purposes. In 2008, IEI Technologies released a modern motherboard for Intel Core 2 Duo processors which, in addition to other special I/O features,

4830-462: Was rare. Users frequently had to configure parameters when adding a new device, such as the IRQ line, I/O address , or DMA channel. MCA had done away with this complication and PCI actually incorporated many of the ideas first explored with MCA, though it was more directly descended from EISA. This trouble with configuration eventually led to the creation of ISA PnP , a plug-n-play system that used

4900-679: Was shown to be the result of a faulty electrolyte formulation, an issue termed capacitor plague . Modern motherboards use electrolytic capacitors to filter the DC power distributed around the board. These capacitors age at a temperature-dependent rate, as their water based electrolytes slowly evaporate. This can lead to loss of capacitance and subsequent motherboard malfunctions due to voltage instabilities. While most capacitors are rated for 2000 hours of operation at 105 °C (221 °F), their expected design life roughly doubles for every 10 °C (18 °F) below this. At 65 °C (149 °F)

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