For example in figure 622 we might decide that a

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Unformatted text preview: hile the cost of a megabyte of disk storage has plummeted by a factor of 50,000 since 1980, access times have improved much more slowly, by only a factor of 10 or so (Figure 6.15(c)). These startling long-term trends highlight a basic truth of memory and disk technology: it is easier to increase density (and thereby reduce cost) than to decrease access time. Metric $/MB Access (ns) 1980 19,200 300 1985 2,900 150 1990 320 35 1995 256 15 2000 100 3 2000:1980 190 100 (a) SRAM trends Metric $/MB Access (ns) Typical size (MB) 1980 8,000 375 0.064 1985 880 200 0.256 1990 100 100 4 1995 30 70 16 2000 1 60 64 2000:1980 8,000 6 1,000 (b) DRAM trends Metric $/MB seek time (ms) typical size (MB) 1980 500 87 1 1985 100 75 10 1990 8 28 160 1995 0.30 10 1,000 2000 0.01 8 20,000 2000:1980 50,000 11 20,000 (c) Disk trends Metric Intel CPU CPU clock rate (MHz) CPU cycle time (ns) 1980 8080 1 1,000 1985 80286 6 166 1990 80386 20 50 1995 Pentium 150 6 2000 P-III 600 1.6 2000:1980 — 600 600 (d) CPU trends Figure 6.15: Storage and processing tec...
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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.

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