A backplane is a circuit board (usually a printed circuit board) that connects several connectors in parallel to each other, so that each pin of each connector is linked to the same relative pin of all the other connectors, forming a computer bus. It is used as a backbone to connect several printed circuit board cards together to make up a complete computer system. One popular early computer system that used this approach was called the S-100 bus because the connectors used had one hundred pins. Some computers like the Apple II and the IBM PC integrated an internal backplane for expansion cards. Close-up photo of one side of a motherboard PCB, showing conductive traces, vias and solder points for through-hole components on the opposite side. ... An electrical connector is a device for joining electrical circuits together. ... PIN can mean different things: Personal identification number Postal Index Number Personal Internet Name. ... In computer architecture, a bus is a subsystem that transfers data or power between computer components inside a computer or between computers. ... A computer system is an automated data-processing system that uses a programmable electronic device to store, retrieve, and process data. ... The S-100 bus was an early computer bus designed as a part of the Altair 8800, generally considered today to be the first personal computer. The S-100 bus was the first industry standard bus for the microcomputer industry, and S-100 computers, processor and peripheral cards, were produced... The 1977 Apple II, complete with integrated keyboard, color high-resolution graphics, sound, a sleek plastic case, and eight expansion slots. ... IBM PC (IBM 5150) with keyboard and green screen monochrome monitor (IBM 5151), running MS-DOS 5. ... Fitting an expansion card into a motherboard An expansion card in computing is a printed circuit board that can be inserted into an expansion slot of a computer motherboard to add additional functionality to a computer system. ...

Backplanes are normally used in preference to cables because of their greater reliability. In a cabled system, the cables need to be flexed every time that a card is added to or removed from the system; and this flexing eventually causes mechanical failures. A backplane does not suffer from this problem, so its service life is limited only by the longevity of its connectors. For example, the DIN 41612 connectors used in the VMEbus system can withstand 50 to 500 insertions and removals (called mating cycles), depending on their quality. Reliability concerns quality or consistency. ... VMEbus is a computer bus standard originally developed for the Motorola 68000 line of CPUs, but later widely used for many applications and standardized by the IEC as ANSI/IEEE 1014-1987. ...

Active vs. passive

Backplanes have grown in complexity from the simple ISA (Industry Standard Architecture used in the original IBM PC) or S-100 style where all the connectors were connected to a common bus. Because of limitations inherent in the PCI specification for driving slots, backplanes are now offered as passive and active. Passive backplanes offer no active bus driving circuitry. Active backplanes include chips which buffer the various signals to the slots. IBM PC (IBM 5150) with keyboard and green screen monochrome monitor (IBM 5151), running MS-DOS 5. ... The S-100 bus was an early computer bus designed as a part of the Altair 8800, generally considered today to be the first personal computer. The S-100 bus was the first industry standard bus for the microcomputer industry, and S-100 computers, processor and peripheral cards, were produced... 32-bit PCI expansion slots on a motherboard 64-bit PCI expansion slots inside a Power Macintosh G4 The Peripheral Component Interconnect standard (in practice almost always shortened to PCI) specifies a computer bus for attaching peripheral devices to a computer motherboard. ... Buffer can have various meanings: In chemistry, the term buffer refers to a buffer solution used to stabilize the pH (acidity) of a liquid. ...

In any case, a backplane is generally differentiated from a motherboard by the lack of on-board processing power where the CPU is on a plug-in card. An old Octek Jaguar V main board with an AMD 386DX-40 processor. ... Intel 80486DX2 microprocessor in a ceramic PGA package A central processing unit (CPU), or sometimes simply processor, is the component in a digital computer that interprets instructions and processes data contained in software. ...

Backplanes in Storage

Backplanes have also become common place for connecting multiple hard drives to a single disk controller. Backplanes are commonly found in disk enclosures, disk arrays, and even in some servers. Typical hard drives of the mid-1990s. ... The disk controller (or hard disk controller) is the circuit which allows the CPU to communicate with a hard disk, floppy disk or other kind of disk drive. ... A disk enclosure is a computer storage device designed to contain disk drives. ... A disk array is an enterprise storage system which contains multiple disk drives. ... In information technology, a server is a computer system that provides services to other computing systems—called clients—over a network. ...