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2.7 / KEY TERMS, REVIEW QUESTIONS, AND PROBLEMS 59

• Standard Performance Evaluation Corporation: SPEC is a widely recognized or-
ganization in the computer industry for its development of standardized benchmarks
used to measure and compare performance of different computer systems.
• Top500 Supercomputer Site: Provides brief description of architecture and organi-
zation of current supercomputer products, plus comparisons.
• Charles Babbage Institute: Provides links to a number of Web sites dealing with the
history of computers.

2.7 KEY TERMS, REVIEW QUESTIONS,AND PROBLEMS

Key Terms

accumulator (AC) instruction cycle opcode
Amdahl’s law instruction register (IR) original equipment manufac-
arithmetic and logic unit (ALU) instruction set turer (OEM)
benchmark integrated circuit (IC) program control unit
chip main memory program counter (PC)
data channel memory address register SPEC
embedded system (MAR) stored program computer
execute cycle memory buffer register (MBR) upward compatible
fetch cycle microprocessor von Neumann machine
input-output (I/O) multicore wafer
instruction buffer register (IBR) multiplexor word

Review Questions
2.1. What is a stored program computer?
2.2. What are the four main components of any general-purpose computer?
2.3. At the integrated circuit level, what are the three principal constituents of a computer
system?
2.4. Explain Moore’s law.
2.5. List and explain the key characteristics of a computer family.
2.6. What is the key distinguishing feature of a microprocessor?

Problems
2.1. Let A = A(1), A(2), ..., A(1000) and B = B(1), B(2), ..., B(1000) be two vectors
(one-dimensional arrays) comprising 1000 numbers each that are to be added to form
an array C such that C(I) = A(I) + B(I) for I = 1, 2, ..., 1000. Using the IAS in-
struction set, write a program for this problem. Ignore the fact that the IAS was de-
signed to have only 1000 words of storage.
2.2. a. On the IAS, what would the machine code instruction look like to load the con-
tents of memory address 2?
b. How many trips to memory does the CPU need to make to complete this instruc-
tion during the instruction cycle?
2.3. On the IAS, describe in English the process that the CPU must undertake to read a
value from memory and to write a value to memory in terms of what is put into the
MAR, MBR, address bus, data bus, and control bus.