Computer Architecture and Organization Chapter one

Outlines Computer Architecture. Computer Organization. Difference between them. Structure and function of computer.

Computer Architecture Definition: Computer Architecture refer to those attributes that are visible to a programmer. Or Those attributer that have a direct effect on the logical execution of a program.

Computer Architecture(cont..) Attributes like: Instruction set. Number of bits used to represent data. I/O mechanisms Addressing techniques.

Computer Organization Organization refers to operational units and their interconnections that realize the architectural specifications. (Organization is how features are implemented).

Computer Organization(cont..) Attributes are hardware details transparent to programmers Control signals. Interface between computer and peripherals. Memory technology.

What is the difference between them? Architecture is those attributes visible to the programmer Instruction set, number of bits used for data representation, I/O mechanisms, addressing techniques. e.g. Is there a multiply instruction? Organization is how features are implemented Control signals, interfaces, memory technology. e.g. Is there a hardware multiply unit or it is perform by repeated addition? Example: IBM/370 architecture different models (organizations)

Cont.. All Intel x86 family share the same basic architecture The IBM System/370 family share the same basic architecture Organization differs within members of the same family, e.g. floating point numerical co-processors with names like 8087, 80287 and 80387. With very few exceptions, the 80486 and subsequent x86 processors then integrated this x87 functionality on chip.

Structure & Function Computer is a complex system then how can we design/describe it? Hierarchic system: A set of interrelated subsystems, each subsystem hierarchic in structure until some lowest level of elementary subsystems is reached At each level of the system, the designer is concerned with structure and function.

Structure & Function (cont..) Structure is the way in which components relate to each other. Function is the operation of individual components as part of the structure

Function There are four basic computer function: Data processing Data storage Data movement Control

Functional view of computer

Operations (1) Data movement Example from keyboard or mouse to the screen

Operations (2) Storage Example save data to a disk

Operations(3) Processing from/to storage Example updating bank statement

Operation(4) Processing from storage to I/O Example printing a bank statement

Structure Four main structural components CPU Main Memory I/O Devices System Interconnection

Structure-Top Level Peripherals computer Communication Lines Main Memory Central processing unit computer System Interconnection Input Output Communication Lines

Structure – The CPU CPU Registers computer Arithmetic and logic unit computer I/O Internal CPU interconnection CPU System bus Memory Control unit

Structure – The Control Unit Sequencing logic CPU Registers Control unit registers and decoders Internal bus Control unit ALU Control memory