Computer Basics and Generations

What is a Computer?

• An electronic device programmed for specialized tasks
• Its is equipped with input, output, CPU, and storage devices
• Also any electronic device operating under stored instructions
• A computer accepts data like raw facts, figures, and symbols
• It processes this data into information for possible storage

Generation of Computers

• Developments in the semiconductor industry necessitated five computer generations
• First generation computers used vacuum tubes
• Second generation used transistors
• Third generation used integrated circuits (ICs)
• Fourth generation used very large scale integrated circuits
• Fifth generation uses nanotechnology

First Generation Computers (1946-1954)

• Constructed with hundreds of vacuum tubes, resulting in large physical size
• ENIAC (Electronic Numerical Integrator and Computer) was developed in 1946
• ENIAC measured 18 feet by 80 feet and weighed 30 tons
• Had slow processing speeds, generated significant heat, and were very expensive
• Typically used in air-conditioned rooms to manage heat generation

Second Generation Computers (1954-1962)

• Used transistors instead of vacuum tubes, transistors were smaller and more reliable
• Smaller in physical size compared to first generation computers
• Faster processing speeds, less expensive, and generated less heat
• Displayed characteristics of modern computers like disk storage and operating systems

Third Generation Computers (1963-1972)

• Transistors were replaced with integrated circuits (ICs)
• ICs are semiconductor devices with multiple transistors in one component
• This transition led to a significant gain in computational power
• First ICs had small-scale integration (SSI) with about 10 devices per circuit
• Cheaper, smaller, faster and generated less heat than previous generations

Fourth Generation Computers (1972-1984)

• Considered modern day computers
• Computers used very large scale integrated circuits (VLICs)
• VLICs fit millions of components onto a small chip
• Cheaper, smaller, faster, and generated less heat

Fifth Generation Computers (Present and Beyond)

• Based on artificial intelligence, still in development
• Voice recognition is one of applications
• Parallel processing and superconductors are helping to realize artificial intelligence
• Quantum computation, molecular and nanotechnology will change computers in the future
• Goal is to develop devices that respond to natural language inputs
• Goal is to develop devices capable of learning and self-organization

Classification of Computers

• Here are three ways of classification
• By data representation
• By purpose
• By processing speed and storage capacity

Classification by Data Representation

• Three types of computers were identified
• Digital: Data represented in discrete form (0s and 1s)
• Analogue: Represents data as continuously variable voltages
• Hybrid: represents data in both continuous and discrete forms

Classification by Purpose

• Can be special purpose or general purpose, depending on flexibility in operations
• Special computers are designed for a specific purpose, and nothing else
• General computers are multi-purpose, like a typical desktop computer

Classification by Processing Speed and Storage Capacity

• Computers come with varied processing and storage capabilities
• Can be grouped as microcomputers
• Can be grouped as minicomputers
• Can be grouped as mainframes
• Can be grouped as supercomputers

Components of a Computer

• Include electric, electronic, and mechanical components known as hardware

Input/Output Devices

• Translate data going into the computer to binary digits (0s and 1s)
• Also translate binary digits coming out into understandable characters

Input Devices

• Keyboards and pointing devices are a type of input devices
• Source-data entry devices (scanners, digital cameras) are a type of input devices
• Voice and audio/video devices (microphones, video cameras) are a type of input devices
• The keyboard is the most common
• Computer keyboards convert letters, numbers, etc. into electrical signals
• Here are other common methods: scanners, voice, microphone, video

What is Output?

• Data that is processed into a useful form

Output Devices

• Any hardware component that conveys information
• Output devices include display devices, and printers
• Also device like speakers, headphones, and earbuds
• Also data projectors
• Interactive whiteboards provide output
• Force-feedback game controllers provide output
• Tactile output provides output

Storage Devices

• Storage devices are media for storing data
• Also referred to as secondary storage
• They range from personal computer diskette drives to video servers

Storage Devices (Physical Parts)

• Consist of 2 physical parts
• The storage medium stores information and software
• The device reads and writes the storage medium
• Cassette or CD is the storage medium
• Casette or CD plays reads from the medium

Storage Devices (Categories)

• Can be categorized by two methods
• Storage method is using technology for writing information on the medium
• Access method is the order in which information is written and read

Storage Devices (Access Methods)

• The 2 main access methods is sequential and direct
• Cassettes use sequential method; music tracks are stored sequentially
• A particular track cannot be accessed without passing over preceding tracks
• CDs use direct access
• With CDs, any track can be played without fast forwarding or rewinding

Types of Storage Devices

• Tape storage devices use sequential access and magnetic storage
• Disk devices use direct access and magnetic, optical, or magneto-optical storage

Tape Storage Devices

• Simply called tape drives
• Used to be common for large computer systems
• Lately they are used for backup and archiving on large systems
• A magnetic method of storage and a sequential method of access writes to tape
• Similar to cassette tapes

Tape Storage Devices

• A magnetic tape is a thin plastic with magnetic coating
• The magnetic surface is split into columns across the tape, and tracks along its length
• A cell is the intersection of a track and column, which is magnetized (on) or un-magnetized (off)

Disk Storage Devices

• Named because of the shape of their storage medium
• The storage medium known as a disk
• Information is written on tracks in concentric circles
• Reading and Writing is done by the disk drive
• The disk is rotated by the disk drive and a read-write head

Disk Storage Devices Storage Methods

• Can use magnetic, optical, or magneto-optical methods to write information
• Data is stored as electromagnetic charges on the metal oxide film coating the disk
• Electromagnetic charges can be easily changed by the disk drive read-write head

Disk Storage Devices Storage Capacity

• Storage capacity is measured like internal memory: kilobytes (KB), megabytes (MB), gigabytes (GB)
• Magnetic disks range from a few megabytes to several gigabytes
• Variations of magnetic disks include:
• Floppy disks
• Internal hard disks
• Compact disks
• Hard cards

System Unit

• Contains the computers electronic components used to process data

Inside the System Unit

• A motherboard is the main circuit board
• Computers chips contains integrated circuits

Processor

• The processor is the central processing unit (CPU)
• Interprets and carries out the basic instructions that operate a computer
• Contains a control unit and an arithmetic logic unit (ALU)
• The Control unit directs most operations in the computer
• The Arithmetic logic unit (ALU) performs calculations

Processor Operations

• For every instruction, a processor repeats a set of four basic operations
• This comprises a machine cycle

Processor (Pipelining)

• Many personal computers support pipelining
• The processor begins fetching a second instruction before completing the first

Processor (Heat)

• Generates heat which could cause damage
• Additional cooling methods were developed
• Methods like heat sinks
• Methods like liquid cooling technology
• Methods like heat pipes

Processors (Parallel)

• Parallel processors use multiple processors to simultaneously complete a task
• Massively parallel processing involves hundreds, or thousands of processors

What is Memory?

• Consists of electronic components that store instructions that are waiting

What Does Memory Store?

• Waiting instructions for the processor

• Data needed by these instructions

• Results of processing the data

• Stores three basic categories of items: the operating system; applications; and information

Memory (Addresses and Measurement)

• Each location in memory has an address
• Measurements are kilobytes (KB), megabytes (MB), gigabytes (GB), or terabytes (TB)

Memory (Types)

• The system unit contains two types: Volatile and Nonvolatile

Memory Variations (Ram)

• Three basic types of RAM chips exist: Dynamic (DRAM); Static (SRAM); Magneto resistive (MRAM)

Solid State Memory

• Flash memory can be erased electronically and rewritten
• CMOS (Complementary metal-oxide semiconductor memory) technology provides high speeds

Memory (Access Time)

• Access time is the amount of time it takes the processor to read from memory
• Access is measured in nanoseconds

Expansion Slots and Adapter Cards

• An expansion slot is a socket on the motherboard used to hold an adapter card
• An adapted card enhance functions through peripherals

Expansion Slots and Adapter Cards (Plug and Play)

• The computer automatically configures card and peripherals when installed

Expansion Slots and Adapter Cards (Flash Memory)

• Removable flash memory includes
• Memory cards
• USB flash drives
• PC Cards
• ExpressCard modules

What are Ports?

• A port is where a peripheral attaches or communications with the system unit

Ports and Connectors

• On a notebook, the ports are on back, front, and/or sides

Ports and Connectors (USB)

• A USB port can connect 127 different peripherals with single connector
• Allows attachment with a USB hub

Ports and Connectors (Bluetooth)

• A bluetooth wireless port adapter converts a USB port to bluetooth

Buses

• Allows devices both inside and attached to the system unit to communicate
• Data bus
• Address bus
• Control bus
• Word size is the number of bits the processor can interpret.

Bays

• An opening inside system unit to install additional equipment
• Holds disk drives

Power Supply

• Power supply converts wall power to DC
• Some external peripherals have an external AC adapter

Software

• Consists of instruction to perform a task
• Classified into system and application software

System Software

• Consists of programs that control or maintain operations of the computer and devices

Operating Systems

• Programs coordinate and act as computer hardware resources

Types of Operating Systems

Utility Programs

• A type of system software that allows a user to perform maintenance tasks
• Includes tasks like: Disk defragmenter, Disk cleanup, file manager, etc.

Application Software

• Make users more productive and/or assist with personal tasks

Application and Generic Software

• Software can be generic
• It can also be customized
• Generic software can be used for general purpose tasked, defined by the developer
• Customized software can be used for particular tasks, defined by the user