Computer Organization and Architecture

Babagge's Analytical Engine

A machine designed to store data and then print out the results automatically on a typewriter.

Program Counter (PC)

A register that holds the address of the next instruction to be fetched in the fetch execute cycle.

EDVAC

an arithmetic-only computer working with binary numbers rather than the decimal operations of ENIAC.

After data processing

the result is either stored in the memory for further references, or sent outside through output port

Output unit

this sends the processed results to the user. Output devices display information in a way that the user can understand.

Hollerith & Tabulating Machine

used punch cards to tabulate census data, later became known as IBM

Abacus

The first automatic computer

ENIAC

First electronic computer

Difference Engine

A machine invented by Charles Babbage designed for constructions of tables of elementary fractions, like sines, cosines, and logarithms

Forefathers of Modern Computer

Charles Babbage, Blaise Pascal, Gottfried Wilhelm-von Leibniz

Computer Organization

Concerned with the structure and behaviour of a computer system as seen by the user

Computer Architecture

Concerned with the way hardware components are connected together to form a computer system

Primary function of a computer

Execute a program or sequence of instructions

Augusta Ada Byron

First Computer Programmer

UNIVAC

First commercial computer

Pascaline

First mechanical computing machine

Counting: The Shaman

First way that measured the months and seasons in order to perform religious festivals and ceremonies at the right time.

Five main components of a computer

Input unit, Central Processing Unit, Memory unit Arithmetic & logical unit, Control unit and an Output unit.

Computer Architecture

It acts as the interface between hardware and software.

Computer Organization

It deals with the components of a connection in a system.

Arithmetic Logic Unit (ALU)

It performs arithmetic operations like addition, subtraction, multiplication, division and also the logical operations like AND, OR, NOT operations.

BASIC

Provided ease of programming and easier debugging than machine code or assembly

Examples of Primary Memory

RAM, ROM, Cache

Instruction Register (IR)

Register that holds the instruction currently being executed

2 categories of Memory

primary memory and secondary memory

Babbage's conditional

This allows use to check the current value of <s> in a particular conditional statement.

Computer Architecture

This can be viewed in terms of instructions, addressing modes and registers

Leibniz Step Reckoner

This is a machine capable of doing 4 arithmetic operations and can extract square root.

Pascaline

This is a machine capable of doing two (2) arithmetic operations [addition and subtraction]

Napier's Bone

Used in calculating equations

Computer Architecture

While designing a computer system architecture is considered first

Microsoft

a BASIC compiler produced by Bill Gates and Paul Allein in 1975.

Primary memory

a volatile form of memory that is considered to be the fastest memory that operates at electronic speed.

Function registers

program counters (PC), instruction registers (IR), memory address registers (MAR) and memory data registers (MDR)

Memory unit

referred to as the storage area in which programs are kept which are running, and contains the data needed by the running programs.

Von Neumann Machine

states that data and program can be stored in the same space.

Computer Organization

tells us how exactly all the units in the system are arranged and interconnected (how it does it)

Pascal's Gear System

used as the way an odometer works for counting kilometers.

Input unit

used by computer to read data.

Registers

used for temporary storage of data

Control unit

also known as the nerve center of a computer system

Slide rule

based on Napier's tool. uses various scales and the strategy of logarithms to turn multiplication into addition and division into subtraction

CPU

carries out instructions given by a computer program by performing the basic arithmetic, logical control and input/output (I/O) operations specified by the instructions.

Memory Data Register (MDR)

contains the data to be written into or read from the addressed word of the main memory

Computer Architecture

deals with high-level design issues

Computer Organization

deals with low-level design issues

Polling

enables the processor software to check each of the input and output devices frequently.

Computer Organization

expresses the realization of architecture

Computer Architecture

helps us to understand the functionalities of a system (what the computer does)

Memory Address Register (MAR)

holds the address of the main memory to or from which data is to be transferred

Computer Architecture

involves Logic (Instruction sets, Addressing modes, Data types, Cache optimization)

Computer Organization

involves Physical Components (Circuit design, Adders, Signals, Peripherals)

Control Unit

is a component of a computer's central processing unit that coordinates the operation of the processor. It tells the computer's memory, arithmetic/logic unit and input and output devices how to respond to a program's instructions.

Computer Organization

is done on the basis of architecture

Secondary Memory

memory used when a large amount of data and programs have to be stored for a long-term basis

Interrupt

method provides an external asynchronous input that informs the processor that it should complete whatever instruction that is currently being executed and fetch a new routine that will service the requesting device.