computer fundamentals

1. Fundamentals of Computers
By: S.Dhar

2. What is Computer?
• Derived from word ‘compute’ or ‘CALCULATE’.
• A computer is an electronic device that takes data and instructions
as input, (data, facts & figures) processes the data and produces
useful information as output IN A GIVEN FORMAT.
Data
• the electronic device is known as hardware and the set of
instructions is known as software.
Process
Input
Output
Information
Instructions

3. Information Processing or
Basic Operations of Computer
• Input Data
• Processing
• Storage
• Output Information

4. Anatomy of Computer System
• Keyboard
• Mouse
• Scanner
• Monitor
• Printer
• Speaker
• Primary Memory
• Secondary Memory
• Control unit
• Arithmetic logical unit
• Motherboard
Input devices
Output Devices
Processing units
Storage Management

5. Parts of the Computer

6. Computer Hardware
• Computers use the same basic hardware
• Hardware categorized into five types

7. 1 Processing devices
– a central processing unit (CPU) is the Brain of the
computer that Carries out instructions from the
program &Manipulate data
– Processors made of silicon and copper
– Speed of processor is measured in GHz

8. ALU
– an arithmetic/logic unit (ALU) where math and logic
operations are performed,
– a control unit which directs most operations by
providing timing and control signals,
– and registers that provide short-term data storage and
management facilities.

9. Control Unit
• CU transfers the data and the instruction of the corresponding
operation to the ALU stored with it.
• It fetches an instruction from memory by sending an address
and read command to the memory unit.
• The instruction word(s) stored at the memory location
specified by the address is then transferred to the control unit .
• After decoding this instruction, the control unit transmits the
appropriate signals to the other units in order to execute the
specified operation.
• This sequence of fetch and execute is repeated by the control
unit until the computer is either powered off or reset.

10. Primary storage
 Primary memory is the built in unit of the computer.
 The data is stored in machine in binary format .
– Random Access Memory (RAM)
• Volatile
• Stores current data and programs
• More RAM results in a faster system
• Capacity of RAM is measured in number of Bytes it can
store
– Read Only Memory (ROM)
• Permanent storage of programs
• Holds the computer boot directions

11. Secondary storage
• They represent the external storage devices connected
to the computer.
• Non-volatile memory.
– Hold data and programs permanently
• Classification of secondary storage:
– Magnetic storage
• Floppy and hard drive
• Uses a magnet to access data
– Optical storage
• CD and DVD drives
• Uses a laser to access data
– Flash drive
• Solid state storage device (means no moving
parts)

12. Hard Disk
• Non-removable storage device.
• Several Circular Magnetic Disks are housed in a single case.
• Data is stored as 1s & 0s.
Solid-State Storage
– No moving parts
– Flash memory cards

13. Magnetic media
Floppy disks – The floppy disk is
in a hard case the disk inside is
floppy. Magnetic disks store
binary (a series of 0s and 1s) data
as a magnetic pattern on the disk
surface.
Optical discs
CD-ROM drives – The data is
stored on the disk digitally and a
laser beam is used to read the
data off the disk. Because light is
used to read the disk. CD-ROMs
are read-only disks.
Normally 1.44MB
storage capacity
Normally 600-700MB
storage capacity

14. CD-R/CD-RW – A CD-R has a read/write capability.
Standard CD-R discs can be written to only once. But
there is a type of disc called CD-RW, these discs can
be written, erased and rewritten many times, with
suitable drives.
Magneto-Optical Discs – MO devices write data to a
disc with the help of a laser beam and a magnetic
write-head.
Digital versatile discs (DVDs) – are used to store lots
of data. Any application software that needs six to
seven CD-ROMs for installation could be replaced by
a single DVD.

16. Local Area Network (LAN) - LANs are networks
usually confined to a geographic area, such as a
single building or a college campus. LANs can be
small, linking as few as three computers, but
often link hundreds of computers.
Network Types
WIDE AREA NETWORK (WAN) -
Wide area networking combines multiple lans that are
geographically separated. This is accomplished by
connecting different networks using services such as
dedicated leased phone lines, dial-up phone lines (both
synchronous and asynchronous), satellite links, and data
packet carrier services.

17. Local Area Network (LAN)
Star topology Ring topology Mesh topolog
Bus topology

18. Twisted pair
A basic twisted-pair cable consists of two strands of
copper wire twisted together enclosed in a foil wrap
and woven copper shielding. This twisting reduces
the sensitivity of the cable to outside electro magnetic
interference.
Transmission media

19. Unshielded twisted pair
Unshielded twisted-pair cable doesn’t incorporate a
braided shield into its structure.

20. Coaxial Cable
Coaxial cables were the first cable types used
in LANs. Gets its name because two
conductors share a common axis; the cable is
most frequently referred to as coax.

21. Fiber Optics
The centre conductor of a fiber-optic cable is a
fiber that consists of highly refined glass or plastic
designed to transmit light signals with little loss. A
glass core supports a longer cabling distance, but
a plastic core is typically easier to work with. The
fiber is coated with a cladding that reflects signals
back into the fiber to reduce signal loss. A plastic
sheath protects the fiber.

22. Connectivity Devices
Hubs
The hub's major function is to replicate data it receives from one device attached
to it to all others.

23. Repeaters
Any electrical signal reaching the repeater from one segment, will
be amplified and retransmitted to the other segment. Using
repeaters slows the signal's propagation, and thus the amount of
repeaters should be limited.

24. Bridges
Bridges are used to increase the number of addressable nodes on a network or to
link two geographically distant but similar networks.
Routers
A major feature of a router is that it chooses the best route between networks
that may have multiple paths between them. IP addressing and subnet
masking are used to route packets

25. Modems
A modem is a device that converts digital data originating from a computer to
analog signals used by voice communication networks, such as the telephone
system. A modem may also convert analogue data originating from a (say, a
telephone line) to digital data for use by a computer.
Gateways
Gateways interface two dissimilar networks. Gateways translate one network
protocol into another, thus overcoming both hardware and software
incompatibilities.

26. Communications Media
• Guided transmission media types:
– Available in many types
• Wireless technologies:
– Wireless telecommunications involves the broadcast
of communications in one of three frequency ranges:
• Microwave, radio, and infrared
• Microwave transmission:
– Microwave is a high-frequency (300 MHz–300 GHz)
signal sent through the air
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27. Communications Media (continued)
• 3G wireless communications:
– Supports wireless voice and broadband speed data
communications in a mobile environment
• 4G wireless communications:
– 4G will also provide increased data transmission rates
in the 20–40 Mbps range
• Worldwide interoperability for microwave access
(WiMAX)
– Operates like Wi-Fi, only over greater distances and at
faster transmission speeds
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29. How the Internet Works
• IP protocol:
– Set of rules used to pass packets from one host to
another
• IP address:
– 64-bit number that identifies a computer on the
Internet
• Uniform Resource Locator (URL):
– Web address that specifies the exact location of a
Web page
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30. How the Internet Works (continued)
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31. How the Internet Works (continued)
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32. How the Internet Works (continued)
• Accessing the Internet:
– Access method determined by the size and
capability of your organization or system
• Connect via LAN server:
– Business LAN servers are typically connected to
the Internet at very fast data rates
• Connecting via Internet service providers:
– An ISP is any organization that provides Internet
access to people
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33. How the Web Works
• The Internet:
– Made up of computers, network hardware such as
routers and fiber-optic cables, software, and the
TCP/IP protocols
• The Web:
– Consists of server and client software, the
hypertext transfer protocol (http), standards, and
mark-up languages that combine to deliver
information and services over the Internet
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34. How the Web Works (continued)
• Hyperlink:
– Highlighted text or graphics in a Web document
that, when clicked, opens a new Web page
• Web browser:
– Web client software such as Internet Explorer,
Firefox, and Safari used to view Web pages
• Hypertext Markup Language (HTML):
– Standard page description language for Web
pages
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35. MotherBoard

36. ALU
Internal
Communic
ation
Registers
Control
Unit
CPU Storage/Input Internal Memory
RAM (Read/Write) ROM (Read Only)
BUS SYSTEM
Input Interface Output Interface
Input Devices
Keyboard
Mouse/Joystick
Light pen
Scanner
Infra-red ray
Video Camera
Microphone etc.
Output Devices
VDU(Monitor)
Printer
Speaker etc.
External Storage : Hard Disk,
Floppy Disk, CDROM, Magnetic Tape
Block Diagram of a Modern PC

37. MotherBoard
CPU
RAM
Graphic card
IDE / SATA Peripherals

38. Every thing put together

40. Every thing put together

41. Software
This means computer programs. Software as a whole can
be divided into a number of categories based on the types
of work done by programs:
System software
Application software:- this addresses the multitude of
tasks for which people use computers.
MS Word
Adobe Photoshop
 Operating systems
 Device Drivers

42. System software
– Operating system
• FreeBSD, Macintosh (macosx), Linux (Ubuntu), Windows
(Window 7)
– Network operating system (OS)
• CentOS
– Utility
• AntiVirus

43. Operating System
• OS is system software, which may be viewed as collection of
software consisting of procedures for operating the computer.
• It provides an environment for execution of programs
(application software).
• It’s an interface between user & computer.

44. Contd..
Computer Machine/Hardware
User / Programmer
Operating System
Human Understandable Language
(High Level Language)
Machine Language
(Low Level Language)

45. Types of OS
 Batch Operating System:
 only one program is allowed to run at a time.
 No modification of data while program is in running state.
 If an error is encountered, start the program from scratch.
 Example: DOS
 Interactive Operating System:
 It also can run only one program at a time.
 Modification and entry of data allowed while program is
running.
 Example: Multiplexed Information and Computing Services.

46. Contd..
 Multiuser Operating System:
 Allows multiple user to use the system at the same time or at
different times.
 Example: Linux, Windows 2000.
 Multi-Tasking Operating System:
 Allows more than one program to run at the same time.
 Example: Unix and Windows 2000.
 Multithreading Operating System:
 Allows running of different parts of a program at the same
time.
 Example: Unix, Linux.

47. DOS Operating System
 Short form for Microsoft Disk Operating System.
 Command line user interface.
 Now a days it is not used as a stand alone product, it comes as
an integrated product with Windows.
 In MS-DOS one need to write the commands to accomplish
some task. The commands are categorized into 3 classes:
 Environment command: CLS, TIME, DATE, VER etc.
 File Manipulation command: COPY, DEL, TYPE, DIR etc.
 Utilities: FORMAT, EDIT etc.

48. UNIX Operating System
• Unix controls all the commands generated from the user
keyboards as well as the data generated in such a way that
each user believes that he/she is the only person working on
the computer.
• It is written in C language.
• The properties of Unix are: Multi user and multi tasking
capability, portability, flexibility, security etc.

49. Disk Operating System (DOS)

52. Application software
– Accomplishes a specific task
– Most common type of software
• MS Word, web browser (chrome)
– Covers most common uses of computers

53. Application Software
• Application programs:
– Interact with systems software and the systems
software directs computer hardware to perform
necessary tasks
– Help you perform common tasks, such as:
• Creating and formatting text documents
• Performing calculations
• Managing information
• Some applications are more specialized
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54. Types of Application Software
• Proprietary software:
– One-of-a-kind program for a specific application,
usually developed and owned by a single
company
• Off-the-shelf software:
– Existing software program that is purchased
• Application service provider (ASP):
– Company that can provide software, support,
and computer hardware on which to run the
software from the user’s facilities over a network
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55. 55

56. Personal Application Software
• Word processing
• Spreadsheet analysis
• Database applications
• Graphics program
• Personal information managers
• Software suites and integrated software
packages
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58. Mobile Application Software
• Number of apps for smartphones and other
mobile devices has exploded
• Tens of thousands of applications have been:
– Developed by third parties and available from the
Apple App Store for the iPhone and from the
Android Market for Android handsets
Fundamentals of Information Systems, Seventh Edition 58

59. Enterprise Application Software
• Software that benefits an entire organization
• Enterprise resource planning (ERP) software:
– Set of integrated programs that manage a
company’s vital business operations for an entire
multisite, global organization
– Must be able to support many legal entities,
languages, and currencies
Fundamentals of Information Systems, Seventh Edition 59

60. How Computers Process Data
• The CPU
– Central Processing Unit
– Brain of the computer
– Control unit
• Controls resources in computer
• Instruction set
– Arithmetic logic unit
• Simple math operations
• Registers

62. How brain (CPU) of Computer works

63. Arithmetic Logical Unit

64. CPU Registers (Part of ALU)
• Registers
– High Speed memory located in CPU
– Use to hold data currently been processed
– Stores result of calculation
– Number of bits processor can handle
– Word size
– Larger indicates more powerful computer
– Increase by purchasing new CPU
• 32bit and 64bit common.

65. Control Unit
• Directs and coordinates flow between the CPU
and other devices like a Traffic cop
• Control Unit perform 4 basic operations:
– Fetch- Obtain a program instruction or data from
main memory
– Decode- Translates the instruction into command
– Execute- Carry out the command
– Store- write the result to main memory

66. Machine Cycle
– 4 operation of the CPU comprise of a machine cycle
– Steps by CPU to process data
– Instruction cycle
• CPU gets the instruction
– Execution cycle
• CPU performs the instruction
– Billions of cycles per second

72. Assembler
 Instructions written in assembly language must be translated to
machine language instructions or object code :
 Assembler does this
 One to one translation : One AL instruction is mapped to one ML
instruction.

73. Compiler
 Instructions written in high-level language also must be
translated to machine language instructions : Compiler does this
 Generally one to many translation : One HL instruction is
mapped to many ML instruction.
 Compiled languages include COBOL, FORTRAN, C, etc.
Interpreter
• A translation program that converts each high level program
statement into the corresponding machine code.
• Instead of the entire program, one statement at a time is
translated and executed immediately.