29 Jun
2001
29 Jun
'01
1:14 p.m.
I'll have to drag out my documentation from NEC, I used to work
in the Integration and Test department back when they made the A74T
server systems.
These are EISA boxes, often using the DPT 2012 bus matering boards.
On the NEC systems, there is a 128 bit data path to main memory, and
EISA bus masters can make burst cycles directly over this bus, bypassing
a lot of the usual congestion of early PCI machines.
I don't want to guess at the physical EISA clock without looking it up
first,
but the speed changes when EISA mode transfers control the bus.
Jeff Hellige wrote:
Oh no, EISA
cranks out speed, if you have the right boards.
EISA bus mastering boards can blast 32 bit data directly into RAM
using a seperate data path in the chipset.
What was the bus actually clocked at? I was always under the
impression that with non-bus mastering EISA cards that the additional
speed increase over ISA was just due to the added bus width. Or is
it only clocked at the clock of the ISA bus when an ISA card is
inserted into an EISA slot?
I think I still have a few EISA SCSI boards. Now I'm curious
as to their specs.
Jeff
--
Collector of Classic Microcomputers and Video Game Systems:
Home of the TRS-80 Model 2000 FAQ File
http://www.geocities.com/siliconvalley/lakes/6757