Concepts

Moore's law

Over the history of computing hardware, the number of transistors on integrated circuits doubles approximately every two years.

Compiler

A program that translates high-level language statements into assembly language statements.

Assembler

A program that translates a symbolic version of instructions into the binary version.

High-level programming langrage

A portable language that is composed of words and algebraic notation that can be translated by a compiler into assembly language.

Assembly language

Asymbolic representation of machine instructions.

Machine language

A binary representation of machine instructions.

5 components of a computer

Input, Output, Memory, Control, Datapath

The last two sometimes combined and called the processor.

Instruction set architecture One key interface between the levels of abstraction is the instruction set architecture-the interface between the hardware and low-level software.

Performance

Measurement and Limitation

\[\begin{eqnarray} CPU~time &=& IC \times CPI \times Clock~cycle~time\\\\ &=& \frac{IC \times CPI}{Clock~rate} \end{eqnarray}\] \[Power = Capacitive \times Voltage^2 \times Frequency\]

Fallacies and Pitfalls

Pitfall: Expecting the improvement of one aspect of a computer to increse overall performance by an amount proportional to the size of the improvement.

Amdahl's law

\[ET~after~improvement = \\\\ \frac{ET~affected}{Amount~of~improvement} + ET~unaffected\]

Pitfall: Using a subset of the performance equation as a performance metric.

For example:

\[\begin{eqnarray} MIPS &=& \frac{IC}{ET \times 10^6} \\\\ &=& \frac{Clock~rate}{CPI \times 10^6} \end{eqnarray}\]

Instruction per program is not considered.

Execution time is the only valid and unimpeachable measure of performance.

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