COMPUTER HARDWARE
CHAPTER 3
Lecture-4 / T. Nouf Almujally
1
Outline
Section 1:• History (Homework)• Types of Computer Systems.• The computer System Concept.
Section 2:• Peripherals:
• Input Technologies.• Output Technologies.• Storage Technologies.
Types of Computer Systems
Microcomputer Systems
Computing power now exceeds that of the mainframes of previous generations
Called a personal computer or PC
Relatively inexpensive
Desktop, Hand-held, notebook, laptop, tablet, portable, and floor-standing
Home , personal , professional , workstation or multiuser systems.
Recommended PC Features
Microcomputer Systems
Workstations
-Supports heavy mathematical computing and graphics display demands
Ex:- CAD in engineering,- Portfolio analysis.
Network Servers
-More powerful than workstations
-Coordinates telecommunications and resource sharing
-Supports LAN and Internet.
Terminals
• Terminal: is any input/output device connected by a network to a computer.
• Types:1. Dumb terminals: keyboard and video monitor with
limited processing capabilities.2. Intelligent terminals: networked PCs that perform
data entry and other information processing tasks.• Transaction terminals:
• Use keyboards, touch screen, bar code scanners to capture data , while relying on servers in the network for further transaction processing.
• ex in banks, ATMs machines, airport check-in, POS.
Terminals
3. Network terminals:• Windows terminals: depend on network
servers for Windows software, processing power and storage.
• Internet terminals: depend on the Internet/Intranet servers for their operating systems and application software.
Information Appliances
• Hand-held microcomputer devices, known as personal digital assistants (PDAs). Web-enabled PDAs use touch screens, pen-based
handwriting recognition, or keypads. Mobile workers use to access email or the Web,
exchange data with desktop PCs or Web servers. Latest entrant is the RIM BlackBerry, Apple iPhone.
• Information Appliances may also take the form of:• Video-game consoles and other devices that
connect to your home television set. Enable you to surf the WWW, email, play.
• Telephone-based home appliances that access the web.
Midrange Systems
• High-end network servers that handle large-scale processing of business applications.
Not powerful as mainframes. Less expensive to buy, operate, maintain than mainframes.
• First became popular as minicomputers for scientific research and industrial process monitoring.
• Today used in: Computer-aided manufacturing (CAM). Used as front-end servers to assist mainframes in
telecommunications processing and network management.
Mainframe Computer Systems
• Large, fast, powerful computer systems Large primary storage capacity. High transaction processing Handles complex computations
• Used to: Handle the information processing of major corporation
and government agencies with high transaction processing.
As a superservers for the large client/server networks and high-volume Internet websites for large companies.
Becoming a popular computing platform for: Data mining, warehousing, electronic commerce applications
Supercomputer Systems
• Extremely powerful computer systems designed for scientific, engineering and business applications requiring extremely high speeds for massive numeric computations.
• Markets for supercomputers include: Government research agencies. Large universities. Major corporations.
• Used for global weather forecasting, military defense, astronomy.
• Billions to trillions of operations per second.• Millions of dollars.
The Computer System Concept
• A computer system is an interrelated combination of components performing basic functions to provide end users with a powerful information processing tool.
Computer System
Input
Processing
Output
Storage
Control
Computer System Concept
Computer Processing Speeds
• Early computers• Milliseconds (thousandths of a second)• Microseconds (millionths of a second)
• Current computers• Nanoseconds (billionth of a second)• Picoseconds (trillionth of a second)
• Program instruction processing speeds• Megahertz (millions of cycles per second)• Gigahertz (billions of cycles per second)
• Commonly called “clock speed”
Peripherals
Separate from, and not under the control of, the CPUOffline Devices
Separate from the CPU, but electronically connected to (and
controlled by) itOnline Devices
Generic name for all input, output, and secondary storage devices
Peripheral
Depend on direct connections to the CPU of a computer system
All online devices
Peripherals Advice for a business PC
Input Technologies
• Common input devices: Keyboard.• Pointing Devices:
• Examples:• Electronic mouse and trackball.• Pointing stick• Touch pad.• Touch screen.
Pen-Based Computing
Pen-Based:• Used in Tablet PCs and PDAs
They have a Pressure-sensitive layer, similar to touch screen, under liquid crystal display (LCD) screen.
Software digitizes handwriting, and hand drawing.
Examples: Graphics Tablet, Digitizer.
Speech Recognition Systems
Speech Recognition:• Speech may be the future of data entry because it’s
the easiest, most natural means of human communication.
• Recognizing speech patterns:• Discrete speech recognition: requires
pauses between each word.• Continuous speech recognition (CSR)
recognizes continuous speech.
Speech Recognition Software
• Speech recognition systems digitize, analyze, and classify your speech and its sound patterns:• Compares your speech patterns to a database of sound
patterns• Passes recognized words to your software• Speech recognition SW requires voice recognition
training
• Speaker-independent voice recognition systems:• Allow computers to recognize words from a voice
never heard before• Used in voice-messaging computers, computerized
telephone call switching.
Optical Scanning
• Devices read text or graphics and convert them into digital computer input.• Enables direct entry of data from source documents into a
computer system.
• Document management library system• Scans documents, then organizes and stores them for
easy reference or retrieval.
Sheet-fed scanner Flatbed scanner Optical scanner, copier, fax &
printer
Optical Scanning
Scanners
Optical Character Recognition (OCR)
Compact desktop models are popular for low
cost and ease of use
Larger, more expensive flatbed scanners are
faster, offer high-resolution color scanning
Software that reads characters and codes
Used to read product labels, airline tickets, score
tests, read bar codes
• Magnetic stripe• Read magnetic stripe on credit cards
• Smart cards• Microprocessor chip and memory .
• Digital cameras• Digital Camcorder.
• Magnetic Ink Character Recognition (MICR)• Identification numbers of bank and account printed
in magnetic ink on bottom of check.
Other Input Technologies
Output Technologies
Voice Response Increasingly found along with video displays in business
applications
Video Displays Cathode-ray tube (CRT)
Printed Output Inkjet , laser, multifunction model
Liquid crystal display (LCD)
Plasma displays
Computer Storage Fundamentals
On (1) or Off (0)
Data processed & stored in computer systems through
presence or absence of signals , Either ON or OFFUses two-state
binary data representation
Uses two-state binary data
representation
Smallest element of data
Either 0 or 1BitBit
Group of eight bits, which operate as a single unit
Represents one character or numberByteByte
Representing Characters in Bytes
Storage Capacity Measurement
Kilobyte (KB) One thousand bytes
Megabyte (MB) One million bytes
Gigabyte (GB) One billion bytes
Terabyte (TB) One trillion bytes
Petabyte (PB) One quadrillion bytes
Direct (Random) and Sequential Access
• Direct Access or Random Access• Directly store and retrieve data.• Each storage position has unique address and can be accessed in
same length of time.• Semiconductor memory chips, magnetic disks.
• Sequential Access• Data is stored and retrieved in a sequential process.• Must be accessed in sequence by searching through prior data.• Magnetic tape.
Semiconductor Memory
• The primary storage (main memory) of your computer consists of microelectronic “semiconductor memory “chips.
• It provides you with the working storage your computer needs to process your applications.• Advantages: small size, fast, shock and temperature
resistance• Disadvantages: volatility; must have uninterrupted
electric power or the contents of the memory will be lost. or permanently “burn in” the contents so they cannot be erased by a loss of power.
Types of Semiconductor Memory
Random Access Memory (RAM)
Read-Only Memory (ROM)
1. Most widely used primary storage medium
2. Volatile memory
3. Read/write memory
1. Permanent storage2. Can be read, but not
overwritten3. Frequently used
programs (parts of OS) burned into the chips during manufacturing
4. Called firmware
Flash Drives“ Jump Drive”
1. New type of permanent storage, can store data for unlimited periods without power.
2. Easily transported3. Plugs into any USB
port.
Magnetic Disks
• Used for secondary storage• Fast access and high capacity
• Reasonable cost
Types of Magnetic Disks:• Floppy disks
A single magnetic disk inside a plastic jacket
• Hard disk drives Magnetic disks, access arms, and read/write heads
in sealed module.
Hard Disk Drives & Floppy Disks (diskettes)
Magnetic Disks
• RAID (Redundant arrays of independent disks) Disk arrays of interconnected hard disk drives. They combine from 6 to more than 100 hard disk
drives into a single unit. Provide large capacities (1-2 TB or more). Provide fault tolerant with multiple copies on several
disks Storage area networks (SANs) are high
speed fiber channel local area networks that
can interconnect many RAID units and thus
share their capacity through network servers
with many users.
Magnetic Disks
• Magnetic Tape:• Include Tape reels, and cartridges (larger
capacity).• Lower-cost storage solution• Used for: long term archival and backup
storage
Tape CartridgeTape Reel
Optical Disks
Uses of Optical Disks in Business
Image ProcessingLong-term storage ofhistorical image files
Storage of scanned documents
Publishing Medium
Allows fast access toreference materials
Catalogs, directories ,manuals and so on
Interactive Multimedia
Applications in business
Multimedia encyclopedias, Video games, educational videos, and so
on
Storage Trade-offs
Questions ..
Read from Chapter 3 (Section 1,2)
Resources ..
Top Related