Handlers classification, Computer Engineering

Handler's Classification

In 1977, Wolfgang Handler proposed an detailed notation for expressing the parallelism and pipelining of computers. Handler's classification addresses the computer at three distinct stages:

  • Processor control unit (PCU),
  • Bit-level circuit (BLC),
  • Arithmetic logic unit (ALU),

Theprocessor control unit corresponds to a processor or CPU, the BLC corresponds to the logic circuit needed to perform one- bit operations in the ALU and the arithmetic logic unit corresponds to a functional unit or a processing element.

Handler's classification uses the following three pairs of integers to explain a computer: Computer = (p * p', a * a', b * b')

Whereas, p = number of PCUs

Whereas, p'= number of PCUs that can be pipelined

Whereas, a = number of ALUs controlled by each PCU

Where a'= number of ALUs that can be pipelined

Whereas, b = number of bits in ALU or processing element (PE) word

Whereas, b'= number of pipeline segments on all ALUs or in a single PE

The following operators and rules are used to show the relationship between a variety of elements of the computer:

  • The '*' operator is used to indicate that the units are pipelined or macro-pipelined with a stream of data running through all the units.
  • The '+' operator is used to denote that the units are not pipelined but work on independent streams of data.
  • The 'v' operator is used to denote that the computer hardware can work in one of numerous modes.
  • The '~' symbol is used to specify a range of values for any one of the parameters.
  • Peripheral processors are given away before the main processor using another three pairs of integers. If the given value of the second element of any pair is 1, it may misplaced for brevity.

Handler's classification is the best elaborate by showing how the operators and rules are used to classify numerous machines.

The CDC 6600 has only a single main processor supported by 10 I/O processors. One control unit managed one ALU with a 60-bit word length. The ALU has 10 functional units which can be produced into a pipeline. The 10 peripheral I/O processors may work in parallel with the CPU and with each other also. Every  I/O processor contains one 12-bit ALU. The explanation for the 10 I/O processors is:

                      CDC 6600I/O = (10, 1, 12)

The explanation for the main processor is:

                      CDC 6600main = (1, 1 * 10, 60)

The I/O processors and the main processor can be regarded as forming a macro-pipeline so the '*' operator is used to join the two structures:

CDC 6600 =  (central processor) *(I/O processors) =  (10, 1, 12) * (1, 1 * 10, 60)

Texas Instrument's Advanced Scientific Computer (ASC) have one controller coordinating four arithmetic units. Every arithmetic unit is an eight stage pipeline with 64-bit words. Therefore, we have:

                                    ASC = (1, 4, 64 * 8)

The Cray-1 is a 64-bit single processor computer whose ALU has twelve functional units, eight of which can be joined together to from a pipeline. Dissimilar functional units have from 1 to 14 segments, which can be pipelined also. Handler's description of the Cray-1 is:

                                   Cray-1 =  (1, 12 * 8, 64 * (1 ~ 14))

One more sample system is Carnegie-Mellon University's C.mmp multiprocessor. This system was considered to facilitate research into parallel computer architectures and consequently can be broadly reconfigured. The system exists of 16 PDP-11 'minicomputers' (which has a 16-bit word length), interrelated by a crossbar switching network. Usually, the C.mmp operates in MIMD mode for which the explanation is (16, 1, 16). It can also managed in SIMD mode, where all the processors are synchronized by a single master controller. The SIMD mode description is (1, 16, 16). At last, the system can be rearranged to manage in MISD mode. Here the processors are orderly arranged in a chain with a one  stream of data passing through all of them. The MISD modes description is (1 * 16, 1, 16). The 'v' operator is used to join descriptions of the same part of hardware operating in differing modes. Thus, Handler's description for the total C.mmp is:

                     C.mmp = (16, 1, 16) v (1, 16, 16) v (1 * 16, 1, 16)

 

The '+'  and '*'operators are used to join several separate pieces of hardware. The 'v' operator is of a dissimilar form to the other two in that it is used to join the different operating modes of a one piece of hardware.

While Flynn's classification is simple to use, Handler's classification is cumbersome. The straight use of numbers in the nomenclature of Handler's classification's build it much more abstract and hence hard. Handler's classification is extremely geared towards the description of chains and pipelines. While it is well able to explain the parallelism in a single processor, the range of parallelism in multiprocessor computers is not addressed well.

Posted Date: 3/1/2013 6:50:39 AM | Location : United States







Related Discussions:- Handlers classification, Assignment Help, Ask Question on Handlers classification, Get Answer, Expert's Help, Handlers classification Discussions

Write discussion on Handlers classification
Your posts are moderated
Related Questions
What is the use of isolated I/O configuration.  In isolated I/O configuration the CPU has distinct input and output instructions and each of these instructions is associated wi

What is the necessity of Interfacing in digital ICs and what are the points to be kept in view, while interfacing between TTL gate and CMOS gate? Ans: To realize the optimum

File History.d1 contains a brief history of computing. There are no indentations in this file. Write a program to read this file, inserting five blank spaces at the beginning of ea

Why disable statements are not allowed in functions? If  disble  statement  is used  in function,it  invalids  function  and  its  return  value.  So  disable statements aren't

What is meant by context switch?  Switching the CPU to another process requires saving the state of the old process and loading the saved state for the new process. This task i

The address bus is unidirectional due to the address information is always given by the Micro Processor to address a memory location of an input or output devices.

What is phase encoding or Manchestor encoding?  It is the method for combining clock information with data. It is a scheme in which alters in magnetization occur for each data

What layers are covered under end to end layer connectivity? The layers 4 to 7 of ISO-OSI reference model communicate along with peer entities into the end systems. There is n

Q. What is Cache Memory? Cache memory is a very fast and small memory between CPU and main memory whose access time is closer to processing speed of CPU. It behaves as a high-s

Write a program to input an address i.e. 20 Hex and read the byte (char) contents of that address   Answer   include void main() { char prompt; Date: 26th August 2012