Types of Array Processor

Array Processor performs computations on large array of data. These are two types of Array Processors: Attached Array Processor, and SIMD Array Processor. These are explained as following below. 

1. Attached Array Processor :
To improve the performance of the host computer in numerical computational tasks auxiliary processor is attached to it. 

Attached array processor has two interfaces: 

1. Input output interface to a common processor. 
2. Interface with a local memory. 
    

Here local memory interconnects main memory. Host computer is general purpose computer. Attached processor is back end machine driven by the host computer. 

The array processor is connected through an I/O controller to the computer & the computer treats it as an external interface. 

2. SIMD array processor : 
This is computer with multiple process unit operating in parallel Both types of array processors, manipulate vectors but their internal organization is different. 

SIMD is a computer with multiple processing units operating in parallel. 

The processing units are synchronized to perform the same operation under the control of a common control unit. Thus providing a single instruction stream, multiple data stream (SIMD) organization. As shown in figure, SIMD contains a set of identical processing elements (PES) each having a local memory M. 

Each PE includes – 

• ALU 
• Floating point arithmetic unit  
• Working registers 
   

Master control unit controls the operation in the PEs. The function of master control unit is to decode the instruction and determine how the instruction to be executed. If the instruction is scalar or program control instruction then it is directly executed within the master control unit. 

Main memory is used for storage of the program while each PE uses operands stored in its local memory.