A vintage PC from the early 1990s, this would have been a good performer when new:
"Launched in 1992 and discontinued in 1995, the Intel Xpress product line sat somewhere between the personal computer and the workstation. These were not ordinary home PCs, but modular, expandable machines built for professional and networked business use (and also built like tanks). Three versions were produced: the Xpress Desktop, the Deskside/LX (tower/server), and the Deskside/MX (tower/server with SCSI). The latter models were also rebranded by HP as part of its early NetServer line."
"The (mother) board is built around two distinct chipsets that divide the work between the system core and the expansion bus: Intel’s own Xpress chipset, which handles the processor, memory, cache coherency, and onboard I/O, and a separate EISA chipset, which manages communication with the EISA/ISA expansion bus."
"Up to 12 CPU boards were available for the Xpress motherboards, covering nearly the entire range of 486 and early Pentium processors: 486SX/25, SX/33, DX/33, DX/50, DX2/50, DX2/66, DX4/100, as well as the Pentium 60, 66, 90, and 100. There was even a rare dual-processor board featuring two Pentium 66 MHz CPUs in SMP, compatible only with later revisions of the 8-slot EISA motherboard."
"The EISA bus (Extended Industry Standard Architecture) was one of the early 90s’ attempts to improve the old ISA standard used in IBM-compatible PCs. It was mainly designed for high-end desktops, workstations, and servers, and offered a wider 32-bit data path, bus mastering, and more advanced setup features. One of its biggest advantages was that it stayed fully compatible with older ISA cards, so an EISA machine could still use existing expansion hardware. This made it a good transitional technology rather than a complete break from the past. Even so, EISA did not last very long. It was mostly used in expensive systems, and during the 486 era it had to compete with VESA Local Bus (VLB), which was especially attractive for graphics and storage. In the end, both were replaced by PCI."
Extended Industry Standard Architecture (EISA bus):
"... 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."
...
"EISA was also available on some non-IBM-compatible machines such as the DEC AlphaServer, HP 9000 D-class, SGI Indigo2 and MIPS Magnum."
"... a group of companies led by Compaq (the Gang of Nine) developed a new bus instead. This new bus was named the Extended (or Enhanced) Industry Standard Architecture, or "EISA", while the older AT bus had already been renamed Industry Standard Architecture, or "ISA".[8] This provided virtually all of the technical advantages of MCA, while remaining compatible with existing 8-bit and 16-bit cards, and (most enticing to system and card makers) minimal licensing cost."
"The EISA bus slot is a two-level staggered pin system, with the upper part of the slot corresponding to the standard ISA bus pin layout. The additional features of the EISA bus are implemented on the lower part of the slot connector, using thin traces inserted into the insulating gap of the upper / ISA card edge connector. Additionally, the lower part of the bus has five keying notches, so an ISA card with unusually long traces cannot accidentally extend down into the lower part of the slot."
"EISA itself did not last a decade, being eventually superseded by PCI. However, EISA's legacy was the backwards-compatible standard that ensured that existing software and peripherals would continue to be compatible, as opposed to IBM's MCA bus which would have made these all obsolete. This backwards-compatibility trend for other technological achievements made possible the PC boom of the 1990s, followed by the worldwide adoption of the Internet, and eventually mobile computing in smartphones and tablets."
