Earl Truss <[log in to unmask]> wrote:
> VLB - VESA local bus - was a 32-bit bus system used on 486s mainly for
> video cards and I/O cards for faster access to IDE hard drives.  The
> part of these slots near the back of the computer looked exactly like
> the normal 16-bit card slot but they had an additional set of pins in a
> separate, smaller slot further toward the front of the computer.  VLB
> cards were very long compared to any other cards.  I don't believe any
> Pentium motherboards ever supported VLB cards.

It was kind of a stop-gap measure to get more video bandwidth, since the 16 bit
ISA bus became a limiting factor for moving lots of data for graphics. It
started to become somewhat popular for disk interfaces too (IDE), but if I
recall, it didn't do bus master DMA (or if it did, not very well). About that
time, the VESA organization decided to get anal about enforcing their
intellectual property rights to the standard, and wanted to charge a bunch of
royalties on the use of the bus. About that time, PCI was starting to become
popular, so everybody pretty much switched to that.


--
Russ Poffenberger               Engineering Specialist
Schlumberger Technologies ATE   DOMAIN: [log in to unmask]
1601 Technology Drive
San Jose, Ca. 95110             Voice: (408)437-5254  FAX: (408)437-5246

         PCBUILD maintains hundreds of useful files for download
                     visit our download web page at:
                     http://nospin.com/pc/files.html