Computer Hardware Computer Software

2 Input Devices Secondary Storage Primary Storage Computer Components CPU Output Devices Communications Devices Buses

3 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

4 Examples Of Bytes C: A: T: Note how sum for each byte is an EVEN number EBCDIC ASCII (assume even-parity system)

5 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.

6 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: – Memory And The ALU –CPU and Input And Output Devices

7 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

8 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.

9 Memory Size  Kilobyte (KB): 2 10 Bytes Bytes  Megabyte (MB): 2 10 KB... “Million” Bytes  Gigabyte (GB): 2 10 MB... “Billion” Bytes  Terabyte (TB): 2 10 GB... “Trillion” Bytes

10 Registers  A High Speed Staging Area Within The Computer That Temporarily Stores Data During Processing.  These Areas Called Registers.  Part Of The CPU

11 Four Types Of Registers  Instruction  Address  Storage  Accumulator  Holds The Part Of The Instruction Indicating What The Computer Is To Do Next.  Contains The Memory Location Of Data To Be Used.  Prior To Processing, The Register That Temporarily Stores Data That Have Been Retrieved From Memory.  Stores The Result Of An Arithmetic Or Logical Operator.

12 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

13 How Devices Are Linked BUS CPURAMROM Add-In Boards I/O Devices Ports I/O Devices BUS allows CPU to communicate with RAM, ROM, and peripheral devices connected through either boards or ports.

14 Secondary Storage  Disk  Tape  Optical Storage

15 Optical Storage  CD-ROM: 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

16 Input/Output Devices  Pointing Devices  Source Data Automation  Output Devices

17 Pointing Devices  Keyboard  Mouse –Wired –Infra-red –Trackball –Touch Pad  Joystick  Touch Screen

18 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

19 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)

20 Output Devices  Cathode Ray Tube (CRT)  Printer  Plotter  Voice Output Device

21 Data Processing  Batch Processing –Transaction Data Stored Until Convenient to Process As a Group. Useful for Less Time- sensitive Actions.  On-line Processing –Transaction Data Entered Directly Into System, Constantly Updating Files. Requires Direct-access Devices.

22 Categories Of Computers  Supercomputer  Mainframe  Midrange & Minicomputer  Server  Personal Computer (PC)  Workstation

23 Supercomputer  Highly Sophisticated  Complex Computations  FASTEST CPUs  Large Simulations  State-of-the-art Components  Expensive

24 Mainframe  Largest Enterprise Computer  50 Megabytes to Over One Gigabyte RAM  Commercial, Scientific, Military Applications  Massive Data  Complicated Computations

25 Midrange/Minicomputer  Middle-Range  10 Megabytes To Over One Gigabyte RAM  Universities, Factories, Labs  Used As Front-End Processor For Mainframe

26 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

27 Client Server Requests Data, Service User Interface Application Function Data Application Function Network Resources Client / Server

28 Microcomputer  Desktop or Portable  64 Kilobytes to Over 128 Megabytes RAM  Personal or Business Computers  Affordable  Many Available Components  Can Be Networked

29 Workstation  Desktop Computer  Powerful Graphics  Extensive Math Capabilities  Multi-tasking  Usually Configured To Special Function: e.g.; CAD, Engineering, Graphics

30 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

31 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

32 Managing Hardware Assets  Understand Technology Requirements  Determine Total Cost Of Ownership –Hardware, Software, Installation, Training, Support, Maintenance, Infrastructure  Plan Capacity & Scalability  Identify Trends

Computer Software

34 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

35 Programming Languages: Assembly Language; Fortran; Cobol; Pl / 1; QBasic; Pascal; C; C++; Fourth Generation Languages Operating System: Scheduled Computer Events Allocates Computer Resources Monitors Events Language Translators: Interpreters Compilers Utility Programs: Routine Operations Manage Data Hardware System Software Application Software Software

36 Language Translation  Source Code –High-level Language Instructions  Compiler –Translates High-level Code Into Machine Language  Object Code –Translated Instructions Ready For Computer

37 Graphical User Interface (GUI)  Operating System Uses  Graphic Icons –Icons, Buttons, Bars, Boxes  Pointer –Mouse, Pen, Touch Screen  To Issue Commands  Make Selections

38 32-bit operating system, GUI, multitasking, networking 32-bit operating system not limited to Intel chips. Multitasking, multiprocessing, networking 32-bit. Developed for IBM PS/2. Multitasking, networking Paired-down for handheld computers, wireless communication devices Windows 98 & 95 Windows NT Me & 2000 Windows CE OS/2 Operating SystemFeatures Microcomputer Operating Systems

39 Mac OSFor Macintosh computers. Multitasking. Powerful graphics, multimedia UnixFor powerful microcomputers, workstations, minicomputers. Multitasking, multi-user processing, networking. Portable to various computer platforms DOSFor IBM (PC-DOS) and PC (MS-DOS). Program memory: 640K LinuxFree, reliable alternative to Unix, Windows. Runs on many Platforms. Open-source Microcomputer Operating Systems Operating SystemFeatures

40 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

41 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

42 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

43 Fourth Generation Languages (4GL)  Can Be Employed By End Users  Nonprocedural  Can Develop Applications Quickly  Natural Languages  Six Categories

44 Fourth Generation Languages (4GL)  Query Languages: –Rapidly Retrieve Data –Interactive/ On-line –May Use NATURAL LANGUAGE –Support Special Requests for Data From Relational Databases

45  Report Generators: –Create Customized Reports –Wide Range of Formats  Graphics Languages: –Can Manipulate Drawings, Graphs, Photos, Videos –Presentation Managers Fourth Generation Languages (4GL)

46  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 Fourth Generation Languages (4GL)

47  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 Fourth Generation Languages (4GL)

48 Software Tools  Word Processing  Spreadsheets  Data Management  Presentation Graphics  Integrated Software Suites   Web Browsers  Groupware