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 “allpurpose” 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)
Laptops
More powerful than ENIAC
Palmtops
Speed and size!
Lesson 1.1
Architecture
Four main parts
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–
–
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CPU (central processing unit)
Main memory
Controllers
Peripheral devices
Hardware
– Electronic and mechanical devices integrated or
connected to computer
Lesson 1.2
Schematic
Motherboard
CPU
Arithmetic
Logic Unit
Register
Register
Register
Control
Unit
Peripheral Devices
Lesson 1.2
Main
Memory
Controllers
Main Memory
Stores information to be process or
instructions to be executed
Information stored in bits (binary digits)
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–
–
–
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
Trillion 1,099,511,627,776
Billion 1,073,741,824
Million 1,048,576
Thousand 1,024
240 = terabyte
230 = gigabyte
220 = megabyte
210 = kilobyte
23 = 8 bits (byte)
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 (nonvolatile)
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
ArithmeticLogic Unit (ALU)
– Arithmetic operations
– Logic operations (compares, etc)
Lesson 1.2
Peripheral Devices
Two categories
– Mass storage
Disk drives
Tape drives
CD drives, etc.
– Inputoutput (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
InputOutput 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
Bus
Ring
Irregular
Lesson 1.3
Tree
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
Highlevel language
– Designed to simplify writing programs
– Four types
Procedural (imperative)
Functional
Declarative
Object oriented
Lesson 1.5
Software
Set of instructions read into computer’s
memory and later executed on demand
Two types
– System
Operating systems
Utility programs
Language translators
– Application
Lesson 1.6
Operating System Software
Software written into memory upon startup
Interface between user, computer and
peripherals
Two categories
– Multipleuser computers
– Singleuser computers
Lesson 1.6
Utility Programs
Perform basic operations necessary for
performance of computer system
– File operations
creating, copying, saving
deleting, merging, sorting
Encapsulated with operating systems
Lesson 1.6
Language Translators
Convert programmermade instructions
(source code) into machinelanguage
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