Chapter 1 – Computing Fundamentals

History of Electronic Computers First computer

– ABC (Atanasoff Berry Computer) at Iowa State U.– 1930’s– Solved large numbers of simultaneous equations

First “all-purpose” computer– ENIAC (Electronic Numeric Integrator And

Calculator)– Main idea developed from ABC notes

Both had set wiring –data was input to memory

Lesson 1.1

John von Neumann

Mathematician Proposed alternative to “hard wiring” Introduced concept of stored program

instructions– Both data and instructions were stored– Led to development of multipurpose

computers

Lesson 1.1

Computer Categories

Supercomputers

Mainframe computers

Workstations

Personal computers (microcomputers)

LaptopsMore powerful than ENIAC

PalmtopsSpeed and size!

Lesson 1.1

Architecture

Four main parts– CPU (central processing unit)– Main memory– Controllers– Peripheral devices

Hardware– Electronic and mechanical devices integrated or

connected to computer

Lesson 1.2

Schematic

MainMemory

ControllersPeripheral Devices

CPU

ArithmeticLogic Unit

RegisterRegisterRegister

ControlUnit

Motherboard

Lesson 1.2

Main Memory

Stores information to be process or instructions to be executed

Information stored in bits (binary digits)– Two states: on or off– Byte is 8 bits (character of information like ‘b’)– Grouped into packets called cells or words– Bit pattern is code

Lesson 1.2

Memory Sizes Represented by 2 raised to a power

23 = 8 bits (byte)

210 = kilobyteThousand 1,024

220 = megabyteMillion 1,048,576

230 = gigabyteBillion 1,073,741,824

240 = terabyteTrillion 1,099,511,627,776

Lesson 1.2

Memory Access

RAM– Random access memory– Allows access to cells in no particular order– Volatile

ROM– Read only memory– Cannot be modified by user– Information is permanent (non-volatile)

Serial access– Sequence of cell followed to extract information

Lesson 1.2

Central Processing Unit (CPU) Control Unit

– Controls activities of CPU– Directs flow of instructions– Communicates with ALU

Registers– Rapid access memory cells

Arithmetic-Logic Unit (ALU)– Arithmetic operations– Logic operations (compares, etc)

Lesson 1.2

Peripheral Devices Two categories

– Mass storage Disk drives Tape drives CD drives, etc.

– Input-output (I/O) Monitors Keyboards Printers Speakers, etc.

Lesson 1.2

Mass Storage Devices

Store information Devices that rotate, write to or read from

called drives On/Off (binary)

– Magnetic spots on disks or tape– Pits or “lands” on CDs (optical disks)

Lesson 1.2

Major Differences between Main and Mass Storage

Slower access in mass storage than main Mass storage portable Mass storage usually have greater capacity

and can hold large amounts of information Main memory is volatile and disappears

when power is off, but mass storage permanent (unless deliberately erased)

Lesson 1.2

Input-Output Devices

Input– Convert information coming in to computer

compatible form– Examples: keyboards, scanners, microphones

Output– Convert computer codes into user

understandable format– Examples: monitors, printers, speakers

Lesson 1.2

Controllers

Coordinate actions of peripheral devices with actions of computer

Constant flow between peripheral equipment and controller– Need to know what peripheral equipment is

doing

Lesson 1.2

Networks

Groups of individual computers and peripheral devices linked together to share information and resources

Two categories– Wide area network (WAN)

– Local area network (LAN)

Topology is “shape” of connection

Lesson 1.3

Network Topologies

Ring

Irregular

Bus

Tree

Lesson 1.3

Data Representation

Each bit is either on or off, 1 or 0 ASCII code – 8 bits make a byte Integers represented by base 2, binary system

– Each place position is power of 2 (23+22+21+20) Two other number systems used

– Octal (powers of 8)– Hexadecimal (powers of 16)

Lesson 1.4

Memory Addresses

Every memory cell needs to be addressed Binary code represent address of cell One cell can contain address of another

memory cell

Lesson 1.4

Programming Languages Assembly language

– One level above machine language High-level language

– Designed to simplify writing programs– Four types

Procedural (imperative)FunctionalDeclarativeObject oriented

Lesson 1.5

Software

Set of instructions read into computer’s memory and later executed on demand

Two types– System

Operating systemsUtility programsLanguage translators

– Application

Lesson 1.6

Operating System Software

Software written into memory upon startup Interface between user, computer and

peripherals Two categories

– Multiple-user computers

– Single-user computers

Lesson 1.6

Utility Programs

Perform basic operations necessary for performance of computer system– File operations

creating, copying, savingdeleting, merging, sorting

Encapsulated with operating systems

Lesson 1.6

Language Translators

Convert programmer-made instructions (source code) into machine-language instructions (object code)

Three types– Assemblers: Convert assembly language programs

to object code– Interpreters: Converts an instruction to object code

then executes it– Compilers: Converts entire program to object code

Lesson 1.6

Integrated Development Environment (IDE)

Full package– Compiler– Text editor– Debugging tools

Allows creation, repeated execution and modification of a program– Helps find violations of language rules

Lesson 1.6

Application Software

Many types exist Examples of common types

– Games– Word processing– Database management– Graphics

Program solves practical problem or does specific tasks

Lesson 1.6

Software Engineering

Describes process of software development Process involves many steps (Figure 1.10)

– Definition of problem– Design scheme (breaking into modules)– Coding modules– Testing– Assemble modules– Test until working correctly

Program never “done”

Lesson 1.7

Structured Programming Top-down design

– Defines all tasks program is to perform Tasks separated and functions developed

– Can be designed separately– Two types

Library– Included in C++ development environment

Programmer-defined– Custom made by user

Lesson 1.7

Development of C++ Language

Middle 1980s at Bell Laboratories Bjarne Stroustrup Improvement upon C language Standardized in 1997

– American National Standards Institute (ANSI)– International Standards Organization (ISO)

Object-oriented

Lesson 1.7

C++ Development Environment

Primary goal to produce executable file– Machine language instructions

Allows user to– Create source code– Test it– Modify it– Convert it to executable format

Lesson 1.7

C++ IDE Operations

Editing text to create source code Preprocessing source code Compiling source code and code attached

by preprocessor Linking object code generated in step 3

with other object code

Lesson 1.7

Summary

Computer history Basic computer architecture How bits are stored Differences between programming languages Software engineering C++ language background Using IDE to create executable programs

Learned about:

Chapter 1