Throughout the last 25 years, computers have evolved from being low speed simple machines to high speed behemoths while still remaining affordable. This quantum leap in their performance was made possible by integration of new technology, some of which was made possible through the use of computers themselves. The computers have evolved considerably from being basic set of components made up of Integrated Circuits (ICs) to have a much complex architecture involving microprocessors with millions of mini components on them. The architecture of computer has also evolved with extensive use of new techniques such as pipelining and caching, each of which has evolved itself. The evolution of the performance of computer systems has been supported by integration of these technologies.
Reduced Instruction Set Computer (RISC)
Reduced Instruction Set Computer (RISC)is a processor design strategy that uses a much simplified instructions set than traditional Complex Instruction Set Computers (CISC) .The philosophy behind using RISC was that CISC architecture was not as fast and flexible to growth as RISC.The RISC architecture was shown to be more flexible and faster on several occasions when performing the same operations.
The RISC processors of 1980s were very simple from the ones available currently available in the market. These processors only consisted of thousands of transistors and had a typical instruction set of 32 instructions. However, as the time passed the number of transistors on the CPU also increased along with the instruction set. Earlier, the register size within the processor was also limited to 8-bit; however, as the technology evolved, the size of the registers also increased considerably which allowed for same operations to be performed in lesser processor cycles.Furthermore, the addition of instructions to perform complex operations also allowed the software to run faster as a single complex task which was previously done using multiple instructions could now be performed by a single instruction. Today many of the x86 based processors use RISC as the major design. These processors not only have large registers to process data (at least 32-bits) but also use wider memory bus (64-bits compared to only 24-bits in 1980s) which allows them to move and process more data in one go, making the computer faster (Stokes, 2007). There are also a number of other techniques used to support RISC operations; these include pipelining and cache memory.