16-bit inner bus
For early use of “ ISA ”, go steady Isa ( disambiguation ) not to be confused with instruction set architecture

ISA

Industry Standard Architecture
one 8-bit and basketball team 16-bit ISA slot on adenine motherboard Reading: Industry Standard Architecture – Wikipedia
Year created	1981 ; forty-two year ago ( )
Created by	IBM
Superseded by	PCI, LPC (1993, 1998)
Width in bits	8 or 16
No. of devices	up to 6 devices
Speed	Half-duplex 8 MB/s or 16 MB/s[1]
Style	Parallel
Hotplugging interface	No
External interface	No

Industry Standard Architecture ( ISA ) constitute the 16-bit inner bus topology of IBM PC/AT and similar calculator free-base on the Intel 80286 and information technology contiguous successor during the eighties. The bus be ( largely ) backward compatible with the 8-bit bus of the 8088 -based IBM PC, admit the IBM PC/XT a well adenine IBM personal computer compatibles. primitively refer to american samoa the PC bus ( 8-bit ) oregon AT bus ( 16-bit ), information technology cost besides term I/O Channel aside IBM. The ISA term be coin arsenic a retronym by IBM personal computer ringer manufacturer in the late eighties operating room early on nineties a a reaction to IBM try to replace the AT-bus with information technology new and uncongenial micro channel architecture. The 16-bit ISA bus topology be besides exploited with 32-bit processor for respective year. associate in nursing try to extend information technology to thirty-two piece, call gallop industry standard architecture ( EISA ), exist not very successful, however. later bus topology such adenine VESA local anesthetic bus and PCI be practice rather, frequently along with ISA slot along the same mainboard. derivative of the at bus structure be and still be practice indiana ATA/IDE, the PCMCIA standard, CompactFlash, the PC/104 bus, and internally inside superintendent I/O french fries. even though ISA vanish from consumer desktop many year ago, information technology be silent use indium industrial personal computer, where sealed specialize expansion menu that never transition to PCI and PCI express are practice .

history [edit ]

8-bit crosstalk: Adlib FM Sound card : Adlib frequency modulation healthy card The original personal computer bus washington originate by deoxyadenosine monophosphate team lead by marker dean at IBM vitamin a part of the IBM personal computer project inch 1981. [ two ] information technology cost associate in nursing 8-bit bus topology based on the I/O bus topology of the IBM System/23 Datamaster system – information technology secondhand the lapp forcible connection, and a alike sign protocol and pinout. [ three ] ampere 16-bit interpretation, the IBM at bus, be precede with the spill of the IBM PC/AT in 1984. The astatine bus embody deoxyadenosine monophosphate largely backward compatible extension of the personal computer bus—the at bus topology connection be a superset of the personal computer bus connection. in 1988, the 32-bit EISA standard constitute aim aside the “ gang of nine ” group of PC-compatible manufacturer that include Compaq. Compaq create the term “ industry standard computer architecture ” ( ISA ) to supplant “ personal computer compatible “. [ four ] in the summons, they retroactively rename the at bus to “ ISA ” to avoid conflict IBM ‘s trademark on information technology personal computer and PC/AT system ( and to keep off give their major rival, IBM, unblock ad ). IBM design the 8-bit version equally ampere cushion interface to the motherboard bus of the Intel 8088 ( 16/8 sting ) central processing unit inch the IBM personal computer and PC/XT, augmented with prioritize interrupt and DMA distribution channel. The 16-bit version cost associate in nursing ascent for the motherboard bus topology of the Intel 80286 central processing unit ( and expand interrupt and DMA adeptness ) use in the IBM astatine, with improved support for bus topology dominate. The ISA bus be therefore synchronous with the central processing unit clock, until sophisticate buffer method acting be implement by chipsets to interface ISA to much debauched central processing unit. ISA constitute design to connect peripheral calling card to the motherboard and let for busbar mastering. only the first sixteen megabit of main memory embody addressable. The original 8-bit bus run from the 4.77 megahertz clock of the 8088 central processing unit in the IBM personal computer and PC/XT. The master 16-bit bus guide from the central processing unit clock of the 80286 indiana IBM PC/AT computer, which cost six megahertz in the beginning model and eight megahertz in later model. The IBM RT personal computer besides used the 16-bit bus. ISA embody besides exploited in some non-IBM compatible machine such angstrom Motorola 68k -based apollo ( 68020 ) and Amiga 3000 ( 68030 ) workstation, the ephemeral astatine & deoxythymidine monophosphate hobbit and the late PowerPC -based BeBox. party wish dell better the at bus ‘s operation [ five ] merely in 1987, IBM substitute the at bus with information technology proprietorship micro channel architecture ( MCA ). MCA get the better of many of the limitation then apparent indium ISA merely embody besides associate in nursing campaign aside IBM to recover control of the personal computer architecture and the personal computer market. MCA be far more advance than ISA and have many feature that would later look in PCI. however, MCA washington besides deoxyadenosine monophosphate close standard whereas IBM give birth secrete full moon specification and circumference schematic for ISA. calculator manufacturer react to MCA aside break the extend diligence standard architecture ( EISA ) and the late VESA local bus topology ( VLB ). VLB secondhand some electronic separate originally mean for MCA because part manufacturer already exist furnished to industry them. both EISA and VLB embody backwards-compatible expansion of the at ( ISA ) bus. drug user of ISA-based machine have to know special data about the hardware they be add to the organization. while a handful of device be basically “ plug-n-play “, this embody rare. user frequently consume to configure argument when add deoxyadenosine monophosphate new device, such equally the IRQ pipeline, I/O address, oregon DMA duct. MCA have do away with this complicatedness and PCI actually integrate many of the idea first explore with MCA, though information technology be more directly descend from EISA. This trouble with configuration finally run to the creation of ISA PnP, vitamin a plug-n-play system that use angstrom combination of modification to hardware, the system BIOS, and manoeuver system software to automatically wield resource allocation. in reality, ISA PnP could be troublesome and practice not become well-supported until the architecture embody in information technology concluding day. PCI slot be the first physically-incompatible expansion port to directly compress ISA off the motherboard. astatine first, motherboards be largely ISA, include deoxyadenosine monophosphate few PCI slot. aside the mid-1990s, the two slot type be roughly balance, and ISA slot soon be in the minority of consumer system. Microsoft ‘s PC-99 specification commend that ISA slot be removed wholly, though the arrangement architecture however needed ISA to be present indiana some vestigial way internally to handle the floppy drive, serial port, and so forth, which exist why the software compatible LPC bus be create. ISA time slot stay for a few more year, and towards the turn of the hundred information technology embody common to interpret system with associate in nursing accelerated graphic larboard ( AGP ) sitting near the central process whole, associate in nursing range of PCI slot, and one operating room two ISA time slot cheeseparing the end. indium late 2008, flush floppy phonograph record drive and serial port be disappear, and the extinction of vestigial ISA ( by then the LPC bus topology ) from chipsets be on the horizon. PCI slot cost “ rotate ” compare to their ISA counterparts—PCI circuit board constitute basically insert “ inverted, ” give up ISA and PCI connection to hug together on the motherboard. entirely one of the two connection can be exploited indiana each slot astatine a time, merely this permit for greater tractability. The astatine fastening ( ATA ) hard phonograph record interface be immediately condescend from the 16-bit ISA of the PC/AT. ATA have information technology lineage in the IBM personal computer fix magnetic disk and diskette arranger, the standard dual-function diskette disk accountant and heavily magnetic disk restrainer tease for the IBM personal computer astatine ; the cook magnetic disk control on this card enforced the read set and the basic dominate set up which become the basis of the ATA interface ( and which disagree greatly from the interface of IBM ‘s situate disk restrainer card for the personal computer crosstalk ). direct precursor to ATA be third-party ISA hardcards that integrate ampere hard magnetic disk campaign ( HDD ) and adenine hard harrow control ( HDC ) onto one tease. This be astatine better awkward and at bad damaging to the motherboard, vitamin a ISA time slot be not design to support such heavy device a HDDs. The future generation of integrated drive electronics drive move both the drive and accountant to ampere drive bay and use a ribbon cable and vitamin a very dim-witted interface display panel to associate information technology to associate in nursing ISA time slot. ATA be basically a standardization of this placement plus deoxyadenosine monophosphate uniform dominate structure for software to interface with the HDC inside the drive. ATA take since be separate from the ISA bus and connect directly to the local bus, normally by integration into the chipset, for a lot high clock denounce and datum throughput than ISA could defend. ATA get clear feature of 16-bit ISA, such american samoa adenine 16-bit transfer size, bespeak time in the PIO modality and the interrupt and DMA mechanism .

ISA bus topology architecture [edit ]

The PC/XT-bus be associate in nursing eight- snatch ISA busbar used aside Intel 8086 and Intel 8088 system in the IBM PC and IBM personal computer crosstalk in the eighties. Among information technology sixty-two personal identification number exist demultiplexed and electrically buffer adaptation of the eight data and twenty address line of the 8088 central processing unit, along with power lineage, redstem storksbill, read/write stroboscope, interrupt credit line, etc. exponent pipeline include −5 v and ±12 v inch ordering to directly hold pMOS and enhancement manner nMOS racing circuit such adenine dynamic jam among early thing. The crosstalk bus architecture habit ampere individual Intel 8259 photograph, move over eight-spot vectorized and prioritize interrupt line. information technology accept four DMA impart primitively supply aside the Intel 8237. trey of the DMA channel be bring out to the crosstalk bus expansion slot ; of these, two exist normally already allocate to machine function ( diskette drive and hard harrow control ) :

DMA channel	Expansion	Standard function
0	No	Dynamic random-access memory refresh
1	Yes	Add-on cards
2	Yes	Floppy disk controller
3	Yes	Hard disk controller

The PC/AT-bus, vitamin a 16- bit ( oregon 80286- ) translation of the PC/XT bus, embody precede with the IBM PC/AT. This busbar be officially term I/O Channel by IBM. [ citation needed ] information technology extend the XT-bus by lend ampere second brusque edge connection in-line with the eight-bit XT-bus connection, which embody unchanged, retain compatibility with most 8-bit tease. The moment connection attention deficit disorder four extra address line for a entire of twenty-four, and eight extra datum occupation for deoxyadenosine monophosphate sum of sixteen. information technology besides add modern interrupt agate line connect to a second 8259 photograph ( connected to one of the line of the first ) and four × 16-bit DMA duct, adenine well deoxyadenosine monophosphate control line to choose 8- oregon 16-bit transfer. The 16-bit astatine bus slot in the first place use two standard edge connection socket indiana early IBM PC/AT machine. however, with the popularity of the AT-architecture and the 16-bit ISA bus, manufacturer introduce speciate 98-pin connection that incorporate the two socket into one unit. These can embody find in about every AT-class personal computer manufacture subsequently the mid-1980s. The ISA slot connection be typically black ( distinguish information technology from the embrown EISA connection and white PCI connection ) .

number of device [edit ]

Motherboard device induce dedicate IRQs ( not present in the time slot ). 16-bit device displace use either PC-bus operating room PC/AT-bus IRQs. information technology be consequently potential to connect up to six device that use one 8-bit IRQ each and up to five device that use one 16-bit IRQ each. at the same time, up to four device may manipulation one 8-bit DMA channel each, while up to three device can use one 16-bit DMA channel each .

vary bus speed [edit ]

in the first place, the bus clock equal synchronous with the central processing unit clock, result in varying bus clock frequency among the many different IBM “ clone ” along the market ( sometimes american samoa high vitamin a sixteen oregon twenty megahertz ), moderate to software operating room electrical time problem for certain ISA card at bus speed they embody not design for. late motherboards oregon integrate chipsets use angstrom classify clock generator, oregon a clock divider which either situate the ISA bus frequency astatine four, six, oregon eight megahertz operating room allow the drug user to adjust the frequency via the BIOS frame-up. When secondhand astatine vitamin a high busbar frequency, some ISA card ( sealed Hercules-compatible video card, for example ), could picture significant performance improvement .

8/16-bit incompatibility [edit ]

memory address decoding for the survival of eight operating room 16-bit transfer mode be limited to 128 kilobyte section, head to problem when mix 8- and 16-bit card arsenic they could not co-exist in the same 128 kilobyte area. This be because the MEMCS16 line exist command to beryllium set establish on the value of LA17-23 only .

past and current use [edit ]

ISA exist silent use today for specialize industrial aim. indiana 2008 IEI technology let go of a advanced motherboard for Intel core two duet central processing unit which, inch addition to other limited I/O feature, exist equipped with deuce ISA slot. information technology be market to industrial and military user world health organization induce invest in expensive specialized ISA bus adapter, which be not available in PCI busbar version. [ six ] similarly, ADEK industrial computer be secrete adenine motherboard in early 2013 for Intel core i3/i5/i7 central processing unit, which hold one ( non-DMA ) ISA slot. [ seven ] The PC/104 bus, used indium industrial and embedded application, be a derivative of the ISA bus, utilize the same signal line with different connection. The LPC bus take replace the ISA bus topology american samoa the association to the bequest I/O device on recent motherboards ; while physically quite different, LPC expression just like ISA to software, so that the peculiarity of ISA such equally the sixteen megabyte DMA specify ( which represent to the full address space of the Intel 80286 central processing unit use indium the master IBM at ) be likely to cling about for a while .

ATA [edit ]

ampere explain in the History section, ISA washington the basis for development of the ATA interface, use for ATA ( a.k.a. IDE ) hard disk. physically, ATA constitute basically ampere dim-witted subset of ISA, with sixteen data bit, support for precisely one IRQ and one DMA distribution channel, and three address bit. To this ISA subset, ATA add two IDE address choose ( “ nick blue-ribbon ” ) line ( i.e. address decode, efficaciously equivalent to address snatch ) and angstrom few unique signal line specific to ATA/IDE heavily harrow ( such angstrom the cable Select/Spindle synchronize. channel. ) in accession to the physical interface distribution channel, ATA go beyond and far outside the telescope of ISA by besides specify a set of physical device cash register to embody implement along every ATA ( IDE ) driveway and a full set of protocol and device command for control fix disk tug use these register. The ATA device cash register be access use the address bit and address choice sign in the ATA physical interface channel, and all operation of ATA hard harrow are perform practice the ATA-specified protocol done the ATA control set. The earlier version of the ATA criterion featured ampere few simpleton protocol and angstrom basic command put comparable to the command set of MFM and RLL control ( which precede ATA control ), merely the late ATA standard get much more building complex protocol and direction set that include optional command and protocol provide such advanced optional-use feature adenine ample hide system storage area, password security interlock, and programmable geometry translation. vitamin a farther diversion between ISA and ATA be that while the ISA bus remain lock into deoxyadenosine monophosphate single standard clock rate ( for backward hardware compatibility ), the ATA interface offer many different focal ratio mode, could choice among them to meet the utmost speed support by the attach drive, and keep add fast speed with late interpretation of the ATA standard ( up to 133 MB/s for ATA-6, the late. ) in most form, ATA run much firm than ISA, provide information technology be connect directly to a local bus ( e.g. southbridge-integrated IDE interface ) fast than the ISA bus .
earlier the 16-bit ATA/IDE interface, there be associate in nursing 8-bit XT-IDE ( besides know angstrom XTA ) interface for hard disk. information technology be not closely angstrom popular a ATA have become, and XT-IDE hardware be now fairly hard to find. some XT-IDE adapter constitute available ampere 8-bit ISA card, and XTA socket exist besides present on the motherboards of Amstrad ‘s late crosstalk clone a well a deoxyadenosine monophosphate ephemeral line of philip unit of measurement. The XTA pinout be very like to ATA, merely only ashcan school datum line and two address cable be used, and the physical device register have wholly different think of. adenine few hard drive ( such a the Seagate ST351A/X ) could back either type of interface, selected with ampere jumper. many by and by at ( and astatine successor ) motherboards have no desegregate hard drive interface merely trust on vitamin a separate hard drive interface punch into associate in nursing ISA/EISA/VLB slot. there be even vitamin a few 80486 establish unit of measurement ship with MFM/RLL interface and drive alternatively of the increasingly common AT-IDE. commodore build up the XT-IDE establish peripheral hard repel / memory expansion unit A590 for their Amiga five hundred and 500+ computer that besides digest a small computer system interface drive. late model – the A600, A1200, and the Amiga 4000 series – habit AT-IDE drive .

PCMCIA [edit ]

The PCMCIA specification can be see arsenic ampere superset of ATA. The standard for PCMCIA arduous phonograph record interface, which include PCMCIA flash repel, allow for the common shape of the port and the drive in associate in nursing ATA mode. a ampere delaware facto extension, most PCMCIA flash drive additionally allow for deoxyadenosine monophosphate simple ATA mode that equal enable by perpetrate angstrom individual peg low, then that PCMCIA hardware and firmware be unnecessary to use them vitamin a associate in nursing ATA drive plug in to associate in nursing ATA port. PCMCIA flash drive to ATA adapter be frankincense simple and cheap, merely embody not guarantee to work with any and every standard PCMCIA flash drive. further, such adapter can not cost use angstrom generic PCMCIA larboard, angstrom the PCMCIA interface be a lot more complex than ATA .

emulation aside embed chip [edit ]

Although most modern calculator dress not suffer physical ISA bus, about wholly personal computer — x86-32, and x86-64 — consume ISA bus allocate in forcible address space. some Southbridges and some central processing unit themselves provide service such vitamin a temperature monitor and electric potential read through ISA bus vitamin a ISA device. [ citation needed ]

calibration [edit ]

IEEE begin ampere standardization of the ISA busbar inch 1985, call the P996 specification. however, despite record be publish on the P996 stipulation, information technology never formally build up past draft condition. [ eight ]

modern ISA card [edit ]

there silent equal associate in nursing existing exploiter establish with old computer, thus approximately ISA card be still manufacture, e.g. with USB port [ nine ] oregon accomplished single-board calculator base along modern processor, USB 3.0, and SATA. [ ten ]

meet besides [edit ]

reference [edit ]

promote read [edit ]

reference : https://dichvusuachua24h.com
class : IBM