The Acorn System was a series of modular microcomputer systems based on rack-mounted Eurocards developed by Acorn Computers from 1979 to 1982, aimed primarily at industrial and laboratory use, but also home enthusiasts.
28-502: (Redirected from System II ) System Two , System II or System 2 may refer to: Computing [ edit ] Acorn System 2 , the early microcomputer Atari System 2 , the arcade game platform by Atari Apple System 2 , the operating system version for the Apple Macintosh Capcom System 2 , an arcade system board in the 1990s Cromemco System Two ,
56-525: A 6809 or a faster 6502. The Acorn System 1, initially called the Acorn Microcomputer (Micro-Computer), was intended for hobbyists. It was based on the MOS 6502 CPU , and produced by British company Acorn Computers from 1979. It was a small machine built on two Eurocard -standard circuit boards and it could be purchased ready-built or in kit form. The Acorn System 2 was offered as
84-433: A computer bus to an external backplane, usually located in an enclosure, to provide more or different slots than the host computer provides. These cable sets have a transmitter board located in the computer, an expansion board in the remote backplane, and a cable between the two. Backplanes have grown in complexity from the simple Industry Standard Architecture (ISA) (used in the original IBM PC ) or S-100 style where all
112-601: A computer system by Cromemco from 1978 Channel F System II , game console by Fairchild Digital Access Signalling System 2 , the protocol by British Telecom Global File System 2 , the file system by Red Hat Master System II , the 8-bit video game console by Sega Namco System 2 , the arcade system board by Namco Sega System 2 , an arcade system board in the 1990s S2 (programming language) , style system 2 Other [ edit ] System 2 in Trilogy , an album from rock band Angeldust Super System 2 ,
140-486: A keyboard interface, became the basic CPU card of the system. A series of interchangeable expansion cards were then developed: additional RAM cards; a card containing the Acorn System BASIC interpreter on ROM; a 40×25 character VDU card, and a UHF adaptor for it; interface cards; a floppy disk controller ; Econet network cards; an 80×25 character VDU card; and later also alternate processor cards, offering
168-484: A keyboard. The Acorn System 4 was similar to the System 3, but in a double height frame, containing fourteen slots in the lower frame, and two floppy disk drives in the upper half of the frame above them. With casing, power supply, and a basic 16K of RAM it was being offered for £1525 in 1982 (again, plus extra for the keyboard). The Acorn System 5 was the final Acorn rack-mounted system, released in 1983. It
196-441: A midplane is often useful in larger systems made up primarily of modules attached to the midplane. Midplanes are often used in computers, mostly in blade servers , where server blades reside on one side and the peripheral (power, networking, and other I/O) and service modules reside on the other. Midplanes are also popular in networking and telecommunications equipment where one side of the chassis accepts system processing cards and
224-491: A particular slot type may be limited in terms of what is currently offered by motherboard manufacturers. However, backplane architecture is somewhat unrelated to the SBC technology plugged into it. There are some limitations to what can be constructed, in that the SBC chip set and processor have to provide the capability of supporting the slot types. In addition, virtually an unlimited number of slots can be provided with 20, including
252-468: A system by Acorn Computers from 1980. It was the successor to the Acorn Microcomputer (renamed the Acorn System 1 ). The system comprised four Eurocard -sized printed circuit boards mounted in a 19 inch sub-rack frame on an 8-slot backplane , plus a (separately supplied) additional external keyboard. The four PCB cards contained respectively: The CPU card and cassette interface card were
280-469: The Altair 8800 used a backplane for the processor and expansion cards . 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 or removed from the system; this flexing eventually causes mechanical failures. A backplane does not suffer from this problem, so its service life is limited only by
308-600: The SGPIO protocol as means of communication between the host adapter and the backplane. Alternatively SCSI Enclosure Services can be used. With Parallel SCSI subsystems, SAF-TE is used. A single-board computer meeting the PICMG 1.3 specification and compatible with a PICMG 1.3 backplane is referred to as a System Host Board . In the Intel Single-Board Computer world, PICMG provides standards for
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#1732776846483336-469: The Acorn-standard bus during the 1980s, but ultimately went into receivership in 1989. Placing the two Eurocards from the original Acorn Microcomputer onto a backplane made the system straightforward to expand in a modular way. The original I/O card, minus its keypad and LED display, became the cassette interface card; while the original 6502 CPU card, slightly adapted with the addition of
364-537: The SBC slot, as a practical though not an absolute limit. Thus, a PICMG backplane can provide any number and any mix of ISA, PCI, PCI-X, and PCI-e slots, limited only by the ability of the SBC to interface to and drive those slots. For example, an SBC with the latest i7 processor could interface with a backplane providing up to 19 ISA slots to drive legacy I/O cards. Some backplanes are constructed with slots for connecting to devices on both sides, and are referred to as midplanes. This ability to plug cards into either side of
392-631: The case of Active and Passive Back-planes is while performing maintenance activities i.e. while swapping boards there is always a possibility of damaging the Pins/Connectors on the Back-plane, this may cause full outage for the system as all boards mounted on the back-plane should be removed in order to fix the system. Therefore, we are seeing newer architectures where systems use high speed redundant connectivity to interconnect system boards point to point with No Single Point of Failure anywhere in
420-673: The cassette interface card and cassette operating system of the System 2 machine. The System 3 became the standard workhorse for development in the Acorn lab: the Acorn Atom has been called a cut-down version of the System 3; and it was based on the System 3 that much of the development work for the BBC Micro was done. A minimum configuration contained: In 1982 this was being offered for £775, or £1075 with power supply, casing, and two further 8K RAM cards; plus, again, an additional £136 for
448-496: The connectors were connected to a common bus. Due to limitations inherent in the Peripheral Component Interconnect (PCI) specification for driving slots, backplanes are now offered as passive and active . True passive backplanes offer no active bus driving circuitry. Any desired arbitration logic is placed on the daughter cards. Active backplanes include chips which buffer the various signals to
476-596: The design of Acorn's first all-in-one home computer, the Acorn Atom , released in March 1980; and also much of the circuitry in its successor, the BBC Micro , first shown in late 1981. Acorn's final rack-based machine was the System 5, released in late 1982. The Eurocard business was then sold on to one of its principal resellers, Control Universal Ltd, which continued to develop various cards for industrial use based on
504-440: The link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=System_2&oldid=1037235280 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Acorn System 2 The experience gained in developing this modular system strongly influenced
532-482: The longevity of its connectors. For example, DIN 41612 connectors (used in the VMEbus system) have three durability grades built to withstand (respectively) 50, 400 and 500 insertions and removals, or "mating cycles". To transmit information, Serial Back-Plane technology uses a low-voltage differential signaling transmission method for sending information. In addition, there are bus expansion cables which will extend
560-519: The other connectors, forming a computer bus . It is used to connect several printed circuit boards together to make up a complete computer system . Backplanes commonly use a printed circuit board , but wire-wrapped backplanes have also been used in minicomputers and high-reliability applications. A backplane is generally differentiated from a motherboard by the lack of on-board processing and storage elements. A backplane uses plug-in cards for storage and processing. Early microcomputer systems like
588-480: The other side of the chassis accepts network interface cards. Orthogonal midplanes connect vertical cards on one side to horizontal boards on the other side. One common orthogonal midplane connects many vertical telephone line cards on one side, each one connected to copper telephone wires, to a horizontal communications card on the other side. A "virtual midplane" is an imaginary plane between vertical cards on one side that directly connect to horizontal boards on
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#1732776846483616-744: The other side; the card-slot aligners of the card cage and self-aligning connectors on the cards hold the cards in position. Some people use the term "midplane" to describe a board that sits between and connects a hard drive hot-swap backplane and redundant power supplies. Servers commonly have a backplane to attach hot swappable hard disk drives and solid state drives; backplane pins pass directly into hard drive sockets without cables. They may have single connector to connect one disk array controller or multiple connectors that can be connected to one or more controllers in arbitrary way. Backplanes are commonly found in disk enclosures , disk arrays , and servers . Backplanes for SAS and SATA HDDs most commonly use
644-459: The poker system System Shock 2 , the computer game See also [ edit ] Operating System/2 by IBM Personal System/2 by IBM Preceded by System 1 System 2 Succeeded by System 3 (disambiguation) Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title System 2 . If an internal link led you here, you may wish to change
672-404: The remaining slots, including interface cards, an additional 16K DRAM card, and/or an Econet network adapter; they could also choose to upgrade the processor board to a faster 2 MHz 6502 board. Backplane A backplane or backplane system is a group of electrical connectors in parallel with each other, so that each pin of each connector is linked to the same relative pin of all
700-494: The same cards as used the System 1 , but with the keypad and LED display of the latter left unused. The system could be expanded with any of Acorn's standard Eurocards to add further functionality. In 1982 it was being offered for £320, or £480 with power supply, plus an additional £136 for the optional keyboard. The Acorn System 3 added a floppy disk controller card, floppy disk drive, and disk operating system ROM, replacing
728-420: The slots. The distinction between the two isn't always clear, but may become an important issue if a whole system is expected to not have a single point of failure (SPOF) . Common myth around passive backplane, even if it is single, is not usually considered a SPOF. Active back-planes are even more complicated and thus have a non-zero risk of malfunction. However one situation that can cause disruption both in
756-416: The system. When a backplane is used with a plug-in single-board computer (SBC) or system host board (SHB), the combination provides the same functionality as a motherboard , providing processing power, memory, I/O and slots for plug-in cards. While there are a few motherboards that offer more than 8 slots, that is the traditional limit. In addition, as technology progresses, the availability and number of
784-477: Was mounted in an extra-height single 19-inch frame, which could accommodate two vertically mounted 5 1/4-inch floppy drives, with either seven or ten Eurocard slots. It came complete with a power supply, and was only available fully assembled. As standard it had a 1 MHz 6502, 32K DRAM, a disk controller, and either the 80×25 or the Teletext 40×25 VDU cards. Customers could choose which cards to install in
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