Basic Speed Differential between Parallel and Serial Modes

Basic Speed Differential between Parallel and Serial Modes 

Movement of information in a computer could be likened to a railway system. Carriers of information (bits or bytes) move together (like a train and wagons) from one location to another along electronic tracks. It is important that no two bits of information are mixed up, and therefore all the moves must be carefully synchronized with a clock. This situation resembles the movement of trains on a railway many trains use the same track but are not all in the same place at the same time. The railways run to a timetable. Similarly, information is moved around the computer under the control of the central processor unit (CPU). 

Consider a process that requires the movement of 100 pieces of information — this could be part of a calculation, a bit of word processing, direction of data inputs, and so on. Suppose the 

A very simple illustration in which information from two inputs is dealt with sequentially (serially) by a microprocessor. Input 1 is accepted, and the left-hand series of instructions (program 1) are carried out. Then, Input 2 is examined, and the right-hand set of instructions is followed through. The processes are iterated. If each program (1, 2) takes 1 msec, the total time for one iteration is 2 msec. 

Because the transputer has a 32-bit processor and fast access to considerable quantities of on-chip RAM, it has been called a computer on a chip. Transputers are inherently faster than microprocessors, which have to refer to RAM outside the chip on which they reside. Thus the 100-nsec cycle time used in the above illustration may be only 50 nsec when carried out on the transputer chip. 

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