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 | This article needs additional citations for verification. (June 2012) |
| Enhanced Industry Standard Architecture | |
 Three EISA slots | |
| Year created | 1988 |
|---|---|
| Created by | Gang of Nine |
| Superseded by | PCI (1993) |
| Width in bits | 32 |
| No. of devices | 1 per slot |
| Speed | 8.33 MHz Half-duplex 33 MB/s[1] |
| Style | Parallel |
| Hotplugging interface | No |
| External interface | No |
The Extended Industry Standard Architecture (in practice almost always shortened to EISA and frequently pronounced "eee-suh") is a bus standard for IBM PC compatible computers. It was announced in September 1988 by a consortium of PC clone vendors (the Gang of Nine) as an alternative to IBM's proprietary Micro Channel architecture (MCA) in its PS/2 series.[2]
In comparison with the AT bus, which the Gang of Nine retroactively renamed to the ISA bus to avoid infringing IBM's trademark on its PC/AT computer, EISA is extended to 32 bits and allows more than one CPU to share the bus. The bus mastering support is also enhanced to provide access to 4 GB of memory. Unlike MCA, EISA can accept older ISA cards — the lines and slots for EISA are a superset of ISA.
EISA was much favoured by manufacturers due to the proprietary nature of MCA, and even IBM produced some machines supporting it. It was somewhat expensive to implement (though not as much as MCA), so it never became particularly popular in desktop PCs. However, it was reasonably successful in the server market,[3] as it was better suited to bandwidth-intensive tasks (such as disk access and networking). Most EISA cards produced were either SCSI or network cards. EISA was also available on some non-IBM-compatible machines such as the DEC AlphaServer, HP 9000 D-class, SGI Indigo2 and MIPS Magnum.
By the time there was a strong market need for a bus of these speeds and capabilities for desktop computers, the VESA Local Bus and later PCI filled this niche, and EISA vanished into obscurity.
- ^ Mueller, Scott (2003). Upgrading and Repairing PCS. Que Publishing. p. 310. ISBN 978-0-7897-2974-3.
ISA bus speed.
- ^ Compaq Leads 'Gang of Nine' In Offering Alternative to MCA, InfoWorld, Sep 19, 1988.
- ^ Sean K. Daily (1998). Optimizing Windows NT. Wiley. p. 137. ISBN 978-0-7645-3110-1.
EISA is still found on many of today's modern servers[,] owing to its long-standing presence in the PC server market.