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Unformatted text preview: a linear array of bytes, and the CPU can access each memory location in a constant amount of time. While this is an effective model as far as it goes, it does not reﬂect the way that modern systems really work. In practice, a memory system is a hierarchy of storage devices with different capacities, costs, and access times. Registers in the CPU hold the most frequently used data. Small, fast cache memories near the CPU act as staging areas for a subset of the data and instructions stored in the relatively slow main memory. The main memory stages data stored on large, slow disks, which in turn often serve as staging areas for data stored on the disks or tapes of other machines connected by networks. Memory hierarchies work because programs tend to access the storage at any particular level more frequently than they access the storage at the next lower level. So the storage at the next level can be slower, and thus larger and cheaper per bit. The overall effect is a large pool of memory t...
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This note was uploaded on 09/02/2010 for the course ELECTRICAL 360 taught by Professor Schultz during the Spring '10 term at BYU.
- Spring '10
- The American