Hardware

| Models for Accessing Data | Models for Accessing Instructions |

Another method of organization is by control mechanism. Computer architecture can be classified with two independent dimensions of instructions and data. For parallel computers, the two forms readily used are SIMD (single instruction, multiple data) and MIMD (multiple instruction, multiple data).

SIMD (single instruction, multiple data) classify computers with processors perform the same instruction synchronously on different data. SIMD is used for performing calculations that has high degree of regularity, for instance, image processing. Some examples of SIMD machines are IBM 9000 and Cray C90.

MIMD (multiple instruction, multiple data) are processors may perform different instructions on different data. MIMD is the most common type of parallel computers. Examples of MIMD machines are Blue Horizon and TeraGrid.