Algorithm

Advantages of algorithm:-
1.It provides the core solution to a given problem.The solution can be implemented on a computer system using any programming language of user's choice.
2.It facilitates program development by acting as a design document or a blue print of a given problem solution.
3.It ensures easy comprehension of a problem solution as compared to an equivalent computer program.
4.It eases identification and removal of logical errors in a program.
5.It facilitates algorithm analysis to find out the most efficient solution to a given problem.

Disadvantages of algorithm:-
1.In large algorithms the flow of program control becomes difficult to track.
2.Algorithms lack visual representation of programming constructs like flowchart;thus understanding the logic becomes relatively difficult.

Q.What is a computer?How is it different from human?
The word computer is derieved from Greek word compute which means to calculate.It is an electronic device that can perform a variety of task by executing a given set of instructions.We can input data and after its processed and give the meaningful result in the form of output.It is versatile and can handle multiple tasks like documentation ,accounting,designing,importing education,entertaining and many more.

Computer is different from human in following ways:-
1.Computers have the potential to increase the speed of their impulse transmission exponentially as opposed to humans.
2.Computers have a better ability for multitasking.
3.Computers are good at computations and logic while humans are exemplary in reasoning and imagination.
4.Computers do not think while human can.
5.Human create computer not computer create the human.

    Flowchart 

Purpose of a flowchart:-
1.Provides communication.
2.Provides an overview.
3.Shows all elements and their relationships.
4.Quick method of showing program flow.
5.Checks program logic.
6.Facilitates coding.
7.Provides program revision.
8.Provides program documentation.

Advantages of a flowchart:-
1.Flowchart is an important aid in the development of an algorithm itself.
2.Easier to understand than a program itself.
3.Independent of any particular programming language.
4.Proper documentation.
5.Proper debugging.
6.Easy and clear presentation.

Limitations of a flowchart:-
1.Complex logic.
2.Drawing is time consuming.
3.Difficult to draw and remember.
4.Technical detail.

Q.:-What are the different steps followed in program development?
Ans.:-Program development is a multi step process as follows:
1.Understand the problem
2.Develop a solution-Algorithm-Pseudocode-Flowchart
3.Write a program
4.Test it

For program development,developers are given
Program requirement statement
Design of program interfaces
Overview of the complete project

1.Understand the problem:The first step in solving any problem is understand it.We begin by reading the requirements statements carefully.When we think that we fully understand it,we review our understanding with the user and the system analyst.
Example:Calculate the square footage of house.
The questions that arise are
a)What is definition of square footage?
b)How is it useful?

2.System requirement:We do planning of functional requirements-software's version,Non-functional requirements-Resources-Internet,table,A/Css,coffee.User functional requirements-problem oriented and language used is in simple i.e.English.

3.Analysis:User requirements are transformed to technical terms like Blueprint and also look for different alternatives considering all risks.

4.Design:In UML software users will develop flowcharts,structure charts,data flow diagrams
a)Choose the best way to find solution among different alternatives.
b)Choose in analysis,design files,databases and functions.

5.Code:Important in software development life cycle
a)Uses software for code generation (forward energy)
b)Otherwise go for manual coding.
c)Basic testing is done (compilation)

6.System Test:Test if user requirements are met Blackbox testing:Test programs together,make sure system works as a whole.Whitebox testing:Realease alpha-version to customer,according to his/her feed back we develop beta-version:beta-version is released to selected group of people.

7.Maintenance:Keeps the system working once it has been put in to production.

            CACHE MEMORY   

Advantages of cache memory:-
1.Cache memory is faster than main memory.
2.It consumes less access time as compared to main memory.
3.It stores the program that can be executed within a short period of time.
4.It stores data for temporary use.

Disadvantages of cache memory:-
1.Cache memory has limited capacity.
2.It is very expensive.

Difference between primary memory and secondary memory

Primary memory	Secondary memory
1.It is known as main memory.	1.It is known as backup memory.
2.These are semiconductor memories.	2.These are magnetic and optical memories.
3.It is usually volatile memory.	3.It is non-volatile memory.
4.In this type of memory,data is lost in case power is switched off.	4.In this type of memory,data is permanently stored even if power is switched off.
5.It is working memory of the computer.	5.It is used for storage of data in a computer.
6.A computer cannot run without primary memory.	6.Computer may run without secondary memory.
7.It is faster than secondary memory.	7.It is slower than primary memory.

Some of the facilities offered by operating system (OS) are as following:-

• It communicates with the computer operator by means of the console unit or keyboard.
• It controls the flow of jobs by loading and unloading of programs.
• It under takes error diagnosis and recovery techniques in case of error conditions.
• It allocates peripherals to programs and check their availability.
• OS warns the operator when peripheral units require alteration.
• OS supervises operation including compilation and execution of programmer.

Basic components of PC:-

• Processor
• Hard Disk
• RAM
• Monitor (VDU)
• Keyboard
• Drives-Hard Disk,Floppy Disk and CD-ROM
• Mouse
• Optional Components-Printers,Scanner,Modem,Multimedia kit(Speaker)

OUTPUT DEVICES
List of some output devices are as follows:-

• Monitor
• Printer
• Plotter
• Projector
• Computer Output Microfilm (COM)
• Speaker
• Headphone
• LCD Projection Panels
• Visual Display Unit(VDU)

INPUT DEVICES
List of some input devices are as follows:-

• Keyboard
• Mouse
• Joy Stick
• Light Pen
• Track Ball
• Scanner
• Graphic Tablet
• Microphone
• Magnetic Ink Character Reader (MICR)
• Optical Character Reader (OCR)
• Bar Code Reader
• Optical Mark Reader (OMR)

Difference between interpreter and compiler

Compiler	Interpreter
1.It translates the entire program.	1.It translates the program line by line or statement by statement.
2.It requires more main memory.	2.It requires less main memory.
3.It converts the entire program into machine-code,when all the syntax errors are removed and executes the object code directly.	3.Each time the program is executed ,every line /statement is checked for syntax error and then translated to equivalent machine code.
4.Neither source nor the compiler is required for execution (execute direct object code).	4.Source program and the interpreter is required for execution.
5.It is slow for debugging and testing stage.	5.It is good for fast debugging and at testing stage.
6.Its execution time is less.	6.Its execution time is more.

Difference between RAM and ROM

RAM	ROM
1.It stands for random access memory.	1.It stands for read only memory.
2.It is volatile memory i.e.temporary in nature.	2.It is non-volatile memory i.e.permanent in nature.
3.We can read and write the data present in the RAM.	3.We can only read the data present in ROM.
4.It stores the application programs.	4.It stores the initial program to start a computer.
5.The types of RAM are SRAM,DRAM,SDRAM and DDR.	5.The types of ROM are PROM,EPROM,EEPROM and masked ROM.

Storage units:-

Sr. No.	Unit	Description
1.	Nibble	1 Nibble=4 Bits
2.	Byte	1 Byte=8 Bits
3.	Kilobyte (KB)	1 KB=1024 Bytes
4.	Megabyte (MB)	1 MB=1024 KB
5.	Gigabyte (GB)	1 GB=1024 MB
6.	Terabyte (TB)	1 TB=1024 GB
7.	Petabyte (PB)	1 PB=1024 TB

Applications of Computer
Computers are widely used in following main application areas including scientific,commercial and education that are as follows:-

1.Science and Technology

• Engineering Applications
• Space Technology Applications
• Medical and Medicine Applications
• Defence Applications
• Telecommunication and Networking Applications

2.Commercial Applications

• Banking Applications
• Payroll System
• Industrial Administration Applications
• Business and Administration Applications

3.Educational Applications

• Computer Assisted Learning (CAL)
• Co Aided Instruction (CAI)

Relationship between hardware and software are as following:-
1.Hardware and software are mutually dependent on each other.Both of them must work together to make a computer produce a useful output.
2.Software cannot be utilized without supporting hardware.
3.Hardware without set of programs to operate upon cannot be utilized and is useless.
4.To get a particular job done on the computer,relevant software should be laoded into the hardware.
5.Hardware is a one-time expense.
6.Software development is very expensive and is a counting expense.
7.Different software applications can be loaded on a hardware to run different jobs.
8.A software acts as an interface between the user and the hardware.
9.If hardware is the 'heart' of a computer system,then software is its 'soul'.Both are complimentary to each other.