<Wrong. For a while (in the early 90's) I subscribed to a magazine called
<Defense Electronics. The military had things like 50ns RAM available then
<They are way ahead in many areas; they can afford to (or used to be able to
<anyway) throw money at things, and they often got first dibs.
fast parts...
keep this in mind: Good, fast, cheap, pick any two.
In 1982 NEC and Intel sold 1kx4 (2149), 4kx1(2147) and 16kx1(2167) these
were static mos parts that were anywhere from 35ns to a slow 70ns. They
were widely available and about 7-9x the cost of the 4116 16kx1 dram. The
problem was that '83 brought 64kx1 parts that were as cheap as the 4116,
faster than the 4116 but were about 270ns-Tcy/200ns-Tcas. When your
building a system the 4164 (8 of them) used roughly 240ma. the same memory
using the super fast 2167 (32of them) would eat a whopping 2.16 Amps! Speed
costs! It would also produce more heat.
In late '83 I built a system using a 8088/8mhz with 256k of 2167s besides
being amazingly fast. However 128 of those 2167s tended to heat up the
place and their cost was $768 compared to $128 for the fairly new 4164 and
the $96 for the very new 41256. Also using the newest 256k part would fit
4mb of ram where 256k of static parts fit and still use less than half the
power.
By 1990 32kx8 static rams were in the sub 30ns region. Drams were fairly
fast for page mode but their requirement to have the address stuffed in in
two pieces will add time to the ability to access in exchange for power
savings, pins and packing density. Dram was never as fast but usually
their density was the win. For the current generation of 200mhz and faster
systems cache is barely able to keep up. look at the cost of 16mb of dram
compared to 512k of fast cache ram.
Allison
Received on Tue Nov 04 1997 - 19:57:47 GMT