24-01-2013, 01:05 PM
ADVANCED COMPUTER ARCHITECTURE
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Fundamentals of Computer Design
Computer technology has made incredible progress in the roughly from last 55 years. This rapid rate of improvement has come both from advances in the technology used to build computers and from innovation in computer design. During the first 25 years of electronic computers, both forces made a major contribution; but beginning in about 1970, computer designers became largely dependent upon integrated circuit technology. During the 1970s, performance continued to improve at about 25% to 30% per year for the mainframes and minicomputers that dominated the industry.
The late 1970s after invention of microprocessor the growth roughly increased 35% per year in performance. This growth rate, combined with the cost advantages of a mass-produced microprocessor, led to an increasing fraction of the computer business. In addition, two significant changes are observed in computer industry.
• First, the virtual elimination of assembly language programming reduced the need for object-code compatibility.
• Second, the creation of standardized, vendor-independent operating systems, such as UNIX and its clone, Linux, lowered the cost and risk of bringing out a new architecture.
These changes made it possible to successfully develop a new set of architectures, called RISC (Reduced Instruction Set Computer) architectures. In the early 1980s. The RISC-based machines focused the attention of designers on two critical performance techniques, the exploitation of instruction-level parallelism and the use of caches. The combination of architectural and organizational enhancements has led to 20 years of sustained growth in performance at an annual rate of over 50%. Figure 1.1 shows the effect of this difference in performance growth rates.
The Impact of Time, Volume, Commodification, and Packaging
The cost of a manufactured computer component decreases over time even without major improvements in the basic implementation technology. The underlying principle that drives costs down is the learning curve manufacturing costs decrease over time. As an example of the learning curve in action, the price per megabyte of DRAM drops over the long term by 40% per year. Figure 1.5 plots the price of a new DRAM chip over its lifetime.