The first is in the geometric sense: a vector defines a direction and magnitude. The term «vector» has two common meanings. Scientific computing in this period was still dominated by vector processing. All processors worked under the direction of a single control unit. In this style of machine, known as data-parallel or SIMD, there were several thousand very simple processors. Toward the end of this period a third type of parallel processor was introduced to the market. This distributed memory architecture meant that large systems, using more processors, could be built. On the other hand, Intel instead of using one memory module connected each processor to its own memory and used a network interface to connect processors. All Caching Systems are designed to prevent main memory, RAM, from being an information bottleneck between the CPU and the much slower hard disc drives. Internal and external memory caches are designed to compensate for the discrepancy between the CPU and the slower RAM chips. Most caches copy data from a standard computer memory, RAM, to a type of memory that allows faster data access by the CPU.ĭisk Caches are designed to compensate for the speed discrepancy between the very fast CPU and the much slower disc drives. Each processor had its own local cache memory, a special memory subsystem that temporarily holds data or program instructions to improve overall computer performance. For example, a machine was designed in which 20 processors were connected up to a single memory module.
Prior to 1985 large scale parallel processing was viewed as a research goal. Other new developments were widespread use of computer networks and the increasing use of single-user workstations. The scale of integration in semiconductors continued at an incredible pace – by 1990 it was possible to build chips with a million components – and semiconductor memories became standard on all computers.
The fifth generation saw the introduction of machines with hundreds of processors that could all be working on different parts of single program. The development of the next generation of computer systems is characterized mainly by the acceptance of parallel processing.