Cache-strapped




What is a 256K pipeline burst cache? What does it refer to, what role does it play in the scheme of things, and how important is it as part of the system?
- Glenys McKinnon


The clearest way for me to answer this question is to break it down into several component questions.
What is a cache? Computers spend a lot of time moving bits of information about -- from the hard drive to memory and from memory to the processor. Often the system has to wait for needed information. Frequently the same information is needed repeatedly. By storing often accessed information in an area of faster memory (called a cache) it can be accessed faster. Modern computers have a whole range of different caches, in both software and hardware.
What sort of cache is a 256K pipeline burst cache? The type of cache you are interested in is used because the computer's processor (CPU) can process information faster than it can be pulled from memory (RAM). In 486, Pentium and higher processor systems there are two types of cache: Level 1 (L1) cache is on the processor itself -- it is small, but fast because of its location. Level 2 (L2) cache is on the motherboard. The 256K pipeline burst cache is the Level 2 variety.
Do I need this cache and how large should it be? You don't need any Level 2 cache for your computer to work, but it would be fairly slow without it. 256K is the minimum amount of cache, but many computer systems are now being sold with 512K. Most systems with only 256K can be upgraded to 512K.
Yes, but what is pipeline burst? A computer's main memory is Dynamic RAM (DRAM) while cache memory is Static RAM (SRAM). SRAM is faster than DRAM, but it is also more expensive.
Just to make matters more complicated, there are two major types of SRAM: Asynchronous and Synchronous Burst. The latter type is the faster and more expensive. There are two variations on Synchronous Burst. The most commonly used is Pipeline Burst, and the faster -- and again, more expensive -- is SynchBurst. Many motherboards can be upgraded to the faster types of SRAM.
- Roy Chambers


Category: Hardware
Issue: Nov 1997
Pages: 168-169

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