Transcript MIS 311 Section 701 - Drexel University

Computer Hardware
Computer Software
Computer Components
CPU
Input
Devices
Secondary
Storage
Buses
Output
Devices
Communications
Devices
Primary
Storage
2
How Computers Represent Data
 Bit
– Binary Digit. On/off, 0/1, Magnetic/not
 Byte
– Group of Bits for One Character
• EBCDIC- Extended Binary Coded Decimal Interchange
Code (8 or 9 Bits Per Byte)
• ASCII- American Standard Code for Information
Exchange (7 or 8 Bits Per Byte)
 Parity Bit
– Extra Bit Added to Each Byte to Help Detect
Errors
3
Examples Of Bytes
EBCDIC
ASCII
(assume even-parity system)
C: 1100 0011 0
A: 1100 0001 1
T: 1110 0011 1
100 0011 1
100 0001 0
101 0100 1
Note how sum for each byte is an EVEN number
4
CPU - Central Processing Unit
 It is the Heart of the Computer.
 A Collection Of Electronic Circuits.
 Electronic Impulses Enter The CPU From
An Input Device.
 These Impulses Are Sent Under Program
Control Through Circuits To Create A
Series Of New Impulses.
 A Set Of Impulses Leaves The CPU For
The Output Device.
5
Two CPU Sections
 Arithmetic/Logic Unit (ALU) - Performs
Arithmetic And Logical Operations On Data.
–
–
Arithmetic Operations: + - * /
Logical Operations: Comparing Data
 Control Unit - Section Of The CPU That Directs
The Flow Of Electronic Traffic Between:
–
–
6
Memory And The ALU
CPU and Input And Output Devices
Memory
 Primary (Internal) Storage Holds:
– Programs And Data Passed To The Computer
For Processing
– Intermediate Processing Results
– Output That Is Ready To Be Transmitted To
Secondary Storage Or To An Output Device.
Eg: RAM
7
Memory Address
 Once Programs, Data, Intermediate Results,
And Output Are Stored In Memory, The
CPU Must Be Able To Find Them Again.
 Each Location In Memory Has An Address.
8
Memory Size
 Kilobyte (KB):
210 Bytes... 1024 Bytes
 Megabyte (MB): 210 KB... “Million” Bytes
 Gigabyte (GB): 210 MB... “Billion” Bytes
 Terabyte (TB): 210 GB... “Trillion” Bytes
9
Registers
 A High Speed Staging Area Within The
Computer That Temporarily Stores Data
During Processing.
 These Areas Called Registers.
 Part Of The CPU
10
Four Types Of Registers
 Instruction
 Holds The Part Of The Instruction
Indicating What The Computer Is
To Do Next.
 Address
 Contains The Memory Location
 Storage
 Prior To Processing, The Register
Of Data To Be Used.
That Temporarily Stores Data That
Have Been Retrieved From Memory.
 Accumulator  Stores The Result Of An Arithmetic
Or Logical Operator.
11
Types Of Memory
 RAM : Random Access Memory
– Dynamic: Changes Thru Processing
– Static: Remains Constant (Power On)
 ROM : Read Only Memory
(preprogrammed)
– PROM: Program Can Be Changed Once
– EPROM: Erasable Thru Ultraviolet Light
– EEPROM: Electrically Erasable
12
How Devices Are Linked
I/O
Devices
CPU
RAM
ROM
Add-In
Boards
BUS
Ports
I/O
Devices
13
BUS allows CPU to
communicate with RAM,
ROM, and peripheral
devices connected
through either boards
or ports.
Secondary Storage
 Disk
 Tape
 Optical Storage
14
Optical Storage
 CD-ROM: 500-660 MEGABYTES
– LAND: Flat parts of disk surface reflects light
– PITS: small scratch on surface scatters light
 WRITE ONCE / READ MANY (WORM):
– CD-R: Compact Disk - Recordable
– CD-RW: CD - Rewritable
 DIGITAL VIDEO DISK (DVD): CD size,
up to 10 gigabytes of data
15
Input/Output Devices
 Pointing Devices
 Source Data Automation
 Output Devices
16
Pointing Devices
 Keyboard
 Mouse
– Wired
– Infra-red
– Trackball
– Touch Pad
 Joystick
 Touch Screen
17
Source Data Automation
 Captures Data In Computer Form At
Time & Place Of Transaction
 Barcode
– Identifies Products in Stores, Warehouses,
Shipments
 Magnetic Ink Character Recognition
(MICR)
– Special Ink Identifies Bank, Account,
Amount
18
Source Data Automation
 Pen-Based Input
– Digitizes Signature
 Digital Scanner
– Translates Images & Characters Into Digital Form
 Voice Input Devices
– Converts Spoken Word Into Digital Form
 Sensors
– Devices That Collect Data From Environment for
Computer Input (E.G., Thermometers, Pressure
Gauges)
19
Output Devices
 Cathode Ray Tube (CRT)
 Printer
 Plotter
 Voice Output Device
20
Data Processing
 Batch Processing
– Transaction Data Stored Until Convenient to
Process As a Group. Useful for Less Timesensitive Actions.
 On-line Processing
– Transaction Data Entered Directly Into
System, Constantly Updating Files.
Requires Direct-access Devices.
21
Categories Of Computers
 Supercomputer
 Mainframe
 Midrange & Minicomputer
 Server
 Personal Computer (PC)
 Workstation
22
Supercomputer
 Highly Sophisticated
 Complex Computations
 FASTEST CPUs
 Large Simulations
 State-of-the-art Components
 Expensive
23
Mainframe
 Largest Enterprise Computer
 50 Megabytes to Over One Gigabyte
RAM
 Commercial, Scientific, Military
Applications
 Massive Data
 Complicated Computations
24
Midrange/Minicomputer
 Middle-Range
 10 Megabytes To Over One Gigabyte
RAM
 Universities, Factories, Labs
 Used As Front-End Processor For
Mainframe
25
Client / Server
 Networked Computers
 Client
– User (PC, Workstation, Laptop) Requires Data,
Application, Communications It Does Not
Have
 Server
– Component (Computer) Having Desired Data,
Application, Communications
26
Client / Server
Client
Requests
Server
Data,
Service
27
User Interface
Data
Application
Application Function
Function
Network Resources
Microcomputer
 Desktop or Portable
 64 Kilobytes to Over 128 Megabytes RAM
 Personal or Business Computers
 Affordable
 Many Available Components
 Can Be Networked
28
Workstation
 Desktop Computer
 Powerful Graphics
 Extensive Math Capabilities
 Multi-tasking
 Usually Configured To Special Function:
e.g.; CAD, Engineering, Graphics
29
Centralized / Distributed
 Centralized
– Processing By Central Computer Site
• One Standard
• Greater Control
 Distributed
– Processing By Several Computer Sites Linked
By Networks
• More Flexibility
• Faster Response
30
Sharing Computers
 Network Computer
– Simplified Desktop Computer Stores
Minimum Data to Function (Uses Server)
 Peer-to-Peer Computing
– Networked Computers Share Data, Disk
Space, Processing. Parallel Processing on a
Smaller Scale
31
Managing Hardware Assets
 Understand Technology Requirements
 Determine Total Cost Of Ownership
– Hardware, Software, Installation, Training,
Support, Maintenance, Infrastructure
 Plan Capacity & Scalability
 Identify Trends
32
Computer Software
Software
 Detailed Instructions To Control Computer
Operation
 Program
– Set Of Instructions To The Computer
 Stored
– Program Must Be In Primary Storage
 System Software
– Manages Computer Resources
 Application Software
– Specific Business Application
34
Software
Application Software
System Software
Hardware
Operating System:
• Scheduled Computer
Events
• Allocates Computer
Resources Monitors
Events
Language Translators:
• Interpreters
• Compilers
Programming Languages:
Utility Programs:
• Routine Operations
Manage Data
Assembly Language; Fortran;
Cobol; Pl / 1; QBasic; Pascal; C; C++;
Fourth Generation Languages
35
Language Translation
 Source Code
– High-level Language Instructions
 Compiler
– Translates High-level Code Into Machine
Language
 Object Code
– Translated Instructions Ready For Computer
36
Graphical User Interface (GUI)
 Operating System Uses
 Graphic Icons
– Icons, Buttons, Bars, Boxes
 Pointer
– Mouse, Pen, Touch Screen
 To Issue Commands
 Make Selections
37
Microcomputer Operating
Systems
Operating System
Windows
98 & 95
32-bit operating system, GUI, multitasking,
networking
Windows NT
Me & 2000
32-bit operating system not limited to Intel chips.
Multitasking, multiprocessing, networking
Windows CE
Paired-down for handheld computers, wireless
communication devices
OS/2
38
Features
32-bit. Developed for IBM PS/2. Multitasking,
networking
Microcomputer Operating
Systems
Operating System
Unix
For powerful microcomputers, workstations,
minicomputers. Multitasking, multi-user
processing, networking. Portable to various
computer platforms
Linux
Free, reliable alternative to Unix, Windows. Runs
on many Platforms. Open-source
Mac OS
DOS
39
Features
For Macintosh computers. Multitasking.
Powerful graphics, multimedia
For IBM (PC-DOS) and PC (MS-DOS).
Program memory: 640K
Generations Of Programming
Languages
 1st. Since 1940s. Machine Language:
Binary Code
 2nd. Since Early ’50s. Assembly Language:
Mnemonics for Numeric Code
 3rd. Since Mid ‘50s. High-level Languages
 4th. Since Late ‘70s. Modern Application
Packages
40
High-Level Languages
 FORTRAN (Formula Translator):
Scientific, Engineering Applications
 COBOL (Common Business Oriented
Language): Predominant for Transaction
Processing
 BASIC (Beginners All-purpose Symbolic
Instruction Code): General Purpose PC
Language
41
High-level Languages
 PASCAL: Used to Teach Structured
Programming Practices. Weak in File
Handling, Input / Output
 C and C++: Powerful PC Language for
Developing Applications. Efficient
Execution; Cross Platform. C++ Is Object
Oriented
42
Fourth Generation Languages
(4GL)
 Can Be Employed By End Users
 Nonprocedural
 Can Develop Applications Quickly
 Natural Languages
 Six Categories
43
Fourth Generation Languages
(4GL)
 Query Languages:
– Rapidly Retrieve Data
– Interactive/ On-line
– May Use NATURAL LANGUAGE
– Support Special Requests for Data From
Relational Databases
44
Fourth Generation Languages
(4GL)
 Report Generators:
– Create Customized Reports
– Wide Range of Formats
 Graphics Languages:
– Can Manipulate Drawings, Graphs,
Photos, Videos
– Presentation Managers
45
Fourth Generation Languages
(4GL)
 Application Generators
– User Specifies Computer Needs
– Generator Creates Logic and Code for Application
– Greatly Reduces Development Time
 Very High-level Programming Languages
– Professional Programmer Productivity Tool
– Uses Fewer Instructions
– Reduces Development Time
46
Fourth Generation Languages
(4GL)
 Software Package: Commercially Available
Set of Programs.
– Word Processing
– Spreadsheets
– Data Management
– Presentation Management
 Integrated Software Package Now Combine These
To Simplify Learning And Use
47
Software Tools
 Word Processing
 Spreadsheets
 Data Management
 Presentation Graphics
 Integrated Software Suites
 E-mail
 Web Browsers
 Groupware
48