| OCR Text |
Show 271 sequence, the algorithm control and their matching that determines the amount of temporal entropy inside a computer. Reducing temporal entropy increases control parallelism, which speeds up the computation as well. An optimal computing structure is one that produces the minimum amount of data entropy inside a computing system. In practice, an optimal computing system is seldom found and in most cases one can obtain only a suboptimal solution of a computing system. 2 Naturally, general-purpose computation (e.g., programming) maps a problem structure onto a given and rigid architecture (i.e., computing struc-ture) which increases both spatial and temporal data entropy and the amount of work a computer has to do in order to remove it; while a special-purpose architecture that aims at mapping a computing structure (processors and control) to a problem structure (data pattern and data processing sequence) decreases the amount of data entropy, and therefore, speeds up the computation. Special-purpose computa-tion, governed by physical laws, offers tremendous efficiency in the real computing world.3 The efficiency of special-purpose design in general comes from profound under-standing of the problem, which requires one to incorporate domain knowledge and real human intelligence about the application problem into the computer solution. The area of special-purpose computer software, hardware and architecture design shows the indications of a young science in that the field contains scattered areas of well-defined expertise, but is dominated by ad hoc design principles and heuristics 2 As we have discussed, the first step of discovering a data pattern with minimum spatial data entropy and a data processing sequence with minimum temporal data entropy is the precondition to develop a computing structure. Traditionally, this step has been merged when developing a computing structure and it sometimes has not been noticed. 3The history of human civilization shows evidence of exploring efficiency through specialpurpose tools or equipment. For example, a car is good for a single person to go to work, but may not be as good as a van for family vacation; a farmer would perhaps prefer to keep a truck rather than a sports car; while for people in Utah - with the greatest snow on earth - a car with 4-wheel drive would be desirable. |
