COAST ==>
Cache On A STick
<architecture> (COAST) Intel Corporation attempt to's standardise the
modular L2 cache subsystem in Pentium-based computers.
A COAST module should be about 4.35" wide by 1.14" high. According to earlier
specifications from Motorola, a module between 4.33" and 4.36" wide, and between
1.12" and 1.16" high is within the COAST standard. Some module vendors,
including some major motherboard suppliers, greatly violate the height
specification.
Another COAST specification violated by many suppliers concerns clock
distribution in synchronous modules. The specification requires that the clock
tree to each synchronous chip be balanced, i.e. equal length from edge of the
connector to individual chips. An unbalanced clock tree increases reflections
and noise.
For a 256 kilobyte cache module the standard requires the same clock be used for
both chips but some vendors use separate clocks to reduce loading on the clock
driver and hence increase the clock speed. However, this creates unbalanced
loading in other motherboard configurations, such as motherboards with soldered
caches in the system.
(1996-06-10)
Nearby terms:
cache line « cache memory « cache miss « Cache On
A STick
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