Computer Architecture and Organization

Study Notes

Computer Architecture vs. Computer Organization

Computer Architecture refers to the attributes of a system visible to the programmer, which have a direct impact on the logical execution of a program.
Computer Organization refers to the hardware details transparent to the programmer, including control signals, interfaces between the computer and peripherals, and memory technology used.

Architectural Attributes

Instruction set
Number of bits used to represent various data types
I/O mechanisms
Techniques for addressing memory

Organizational Attributes

Operational units and their interconnections that realize the architectural specifications
Hardware details transparent to the programmer
Control signals
Interfaces between the computer and peripherals
Memory technology used

Cache Memory

Multiple layers of memory between the processor and main memory
Smaller and faster than main memory
Used to speed up memory access by placing in the cache data from main memory that is likely to be used in the near future
Multiple levels of cache (L1, L2, L3, etc.) can be used to improve performance

Registers

Contains a word to be stored in memory or sent to the I/O unit
Specifies the address in memory of the word to be written from or read into the MBR
Instruction buffer register (IBR), Memory buffer register (MBR), Instruction register (IR), Memory address, Program counter (PC), Accumulator (AC), and multiplier quotient (MQ) are types of registers
Used to temporarily hold operands and results of ALU operations from memory

Evolution of the Intel Product Line

Pentium: Introduced superscalar techniques, allowing multiple instructions to execute in parallel
Pentium Pro: Continued superscalar organization with aggressive use of register renaming, branch prediction, data flow analysis, and speculative execution
Pentium II: Incorporated Intel MMX technology for efficient video, audio, and graphics data processing
Pentium III: Incorporated additional floating-point instructions and Streaming SIMD Extensions (SSE)
Pentium 4: Includes additional floating-point and other enhancements for multimedia
Core: First Intel x86 micro-core
Core 2: Extends the Core architecture to 64 bits
Core 2 Quad: Provides four cores on a single chip
More recent Core offerings: Up to 10 cores per chip
Advanced Vector Extensions (AVX) instruction set was added to the architecture

Techniques built into Contemporary Processors

Microprocessor Speed: Pipelining
Branch prediction: Looks ahead in the instruction code fetched from memory and predicts which branches, or groups of instructions, are likely to be processed next
Superscalar execution: Ability to issue more than one instruction in every processor clock cycle
Data flow analysis: Analyzes which instructions are dependent on each other’s results, or data, to create an optimized schedule of instructions
Speculative execution: Executes instructions ahead of their actual appearance in the program execution, holding the results in temporary locations, keeping execution engines as busy as possible

Description

Learn about the attributes of a computer system that impact program execution, including instruction sets, data type representation, I/O mechanisms, and memory addressing. This quiz covers the organizational and architectural attributes of a computer system.