Module 4

Introduction to Computer Architecture

Computer Architecture

It is a coordination of many levels of abstraction under rapid changing set of forces and is used to design, measures and evaluates computer system. It is a combination of Instruction Set Architecture and Computer Organization

Instruction Set Architecture

It covers WHAT the computer does (logical view). timing-independentThe structure of a computer that a programmer must understand to write a correct and timing independent program. Sometimes known as the Programmers Model of the machine.

Computer Organization

It covers HOW the ISA is implemented (physical view).

Interface Design

It is used in many different ways and provides convenient functionality to higher levels of implementation.

Data Movement instructions

Move data from a memory location or register to another memory location or register without changing its form.

Arithmetic and Logic Instruction

Change the form of one or more operands to produce a result stored in another location.

Branch instructions

Use to alter the normal flow of control from executing the next instruction in sequence.

Operations to perform, Where to find the operands, The place to store the result

An Instruction should specify:

Vonn Neuman Architecture

Developed on 1945 by the mathematician and physicist John Von Neumann. It Is a design that popularized the stored-program concept, where instruction data and program data are stored in the same memory.

Data and Instruction

In Vonn Neuman Architecture, _________ are both stored in the main memory

location

In Vonn Neuman Architecture, the content of the memory is addressable by its ________ regardless of what is stored in that location

instructions

In Vonn Neuman Architecture, ________ are executed sequentially unless the order is explicitly modified

CPU

It is the core processing unit that executes instructions.

Bus

It is a communication system that transfers data, addresses, and control signals between the CPU, memory, and I/O devices.

Control

This component manages the operations of the computer. It directs the flow of data between the CPU and other components.

Main memory

This is where data and instructions are stored. It is a crucial part of the computer system that allows for the storage and retrieval of information.

Fetch

In the context of the instruction cycle, when the CPU retrieves the instruction/operand from memory, it is described as?

Decode

In the context of the instruction cycle, when the CPU interprets the instruction and determines what operation needs to be performed, this is described as?

Execute

In the context of the instruction cycle, when the CPU performs the operation specified by the instruction, it is described as?

Addressing Exception

In this type of exception, the memory does not exist or is inaccessible

Operation Exception

In this type of exception, the operation code does not denote a valid operation that can be performed by the processor

Execution Exception

In this type of exception, the instruction logic fails due to the input data.

faster

In the context of memory system design, the ______ the memory, the more costly to build and therefore the smaller in capacity, and conversely, the larger the memory, the slower to access and less costly.

Principle of Locality

Modern memory‐hierarchy design hinges on the _________

Temporal locality

recently accessed data is likely to be accessed again soon

Spatial locality

data near recently accessed locations tends to be used together.

Registers

Small, fast memories located within the CPU used for a particular purpose. Directly accessible by the CPU, enabling rapid data manipulation essential for executing instructions efficiently. Used to hold data temporarily during processing

Cache Memory

Small fast temporary storage area of recently accessed instruction and data. Compared to main memory; acts as a buffer between the CPU and main memory

Level 1 Cache

This level of cache has a memory of (8 KB to 64KB)

Level 2 Cache

This level of cache has a memory of (64KB to 2MB)

Level 3 Cache

This level of cache has a memory of (2MB to 256 MB)

Main Memory

It is the next fastest memory within a computer and is much larger in size. Used to hold both program code (instruction) and data (numbers, strings etc)

Main Memory

In the Fetch-Decode-Execute cycle, the CPU continually reads instructions stored in main memory and executes them. The _______ is where instructions are ‘fetched’ from.

ROM and RAM

There are two types of main memory that are directly accessible by the CPU.

RAM

This type of main memory is a volatile memory, it allows read and write, has fast access times and is available in small capacities ranging from 1 to 256 GB.

Static RAM

This type of RAM retains value indefinitely as long as it is kept powered, it is also faster but more expensive and takes up more space

Dynamic RAM

This type of RAM consists of capacitors that slowly leak their charge over time, it is also cheaper but slower.

SDRAM

A type of DRAM that is synchronized with the clock of the CPU’s system bus.

DDR SDRAM

It is an optimization of SDRAM that allow data to be transferred on both the rising edge and falling edge of clock signal

This is a non-volatile memory, typically read-only, and is used for storing firmware or permanent instructions required for boot up. It also does not need to store much and therefore only has a capacity of a few MB.