1. With a neat schematic block diagram of a digital computer describe its functional units

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  The user can enter the data or program (instructions) to the computer
  
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  system.
  
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  It converts the data into a suitable form that can be understood by the
  
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  Computer.
  
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  The converted data is stored in the form of 0’s and 1’s and then sent to
  
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  Central processing unit
  
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  The user can also interact with other devices such as CPU, MU and
  
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  output unit.
  

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  Accepts the result or data from memory which are in the form of 0’s and 1’s.
  
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  Output the results or data to a form which is suitable for human understanding.
  

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  The data received from the input device is processed in this unit.
  
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  It consists of two functional units: 1. Arithmetic and Logic Unit (ALU)
  

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  An ALU consists of electronic circuitry which performs calculations with basic arithmetic operations such as addition (+), subtraction (-), multiplication (*), division (/).
  
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  It also consists of logic circuitry which performs logic operations like true or false, yes or no.
  

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  The unit controls and co-ordinates all parts of computer system.
  
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  It executes an instruction by signaling to carry out the necessary data transfers and manipulations.
  
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  Identifies what action to be taken. (decoding)
  

This is the storage device where the data and instructions fed by the user are stored.

The computer memory is classified into

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  Main memory: This is the place where the data and instructions supplied by the input devices are stored.
  

When the power goes off.

It consists of RAM and ROM main memories.

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  Secondary memory: This is the permanent memory and also called as back up memory.
  

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  Cache memory: This is the high speed memory and placed between the CPU and the main memory.
  

Mini computer

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  Digital computer:-Computers accept and process data in terms of digital data such as 0’s and 1’s
  

Series of bytes represent data or instruction

E.g. (Personal Digital Computer Assistant)

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  Analog computer:-They accept data whose values keep changing with respect to time.
  

Processing is done on continuously varying signals.

E.g. Speedometer

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  Hybrid Computer:-It is designed to handle digital and analog computers and hence also called analog-digital computer.
  

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  Micro Computer:-It is powerful, easy maintenance, low cost, unporable.
  

They are small in size and do not have large storage capacities. The length of a microcomputer lines in the range 8-32 bits

E.g.: IBM PC, PS/2

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  Mini computer:-Computers with capabilities intermediate of that between main frame and micro computers. Hence called mid-range computers.
  

It is used by small and mid-size business organizations.

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  Main frame computer:-It is more powerful than micro computers and their word length size is 48,60 or 64 bits
  

They are used in research organizations, large industries, and large business and government organizations

They consume more electricity

E.g.: IBM 3000 series, UNIVAC 1180

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  Super computers:-Computers that are used for scientific and engineering applications.
  

They can handle very large data bases or a great amount of data computation.

They can perform one trillion operations per second.

Used in the field of science and defense, designing and launching missiles, weather forecasting, biomedical research

Highest processing speed for at a given time.

E.g: CRAY-3, HITAC S-300

MEMORY

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  The memory is accessible directly to the CPU of the computer.
  
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  The memory is very fast.
  
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  This allows the CPU to store and retrieve data quickly.
  
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  Volatile memory: The memory that loses its contents when the computer is turned off.
  
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  Since the CPU can read the data from the memory or can write the data into the memory they are also called as read-write memories.
  
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  E g. RAM (Random Access Memory): It is possible to read and write the data into the memory. It is temporary memory.
  
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  Non volatile memory: The memory that retains its contents even after the computer is turned off memory. They hold the data permanently.
  
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  E.g. ROM (Read Only Memory): The information stored in it can be only be read.
  

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  Its is the permanent memory which stores large amount of information for a long time
  
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  It’s also called back up memory or auxiliary memory.
  
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  It is connected to CPU and is made of magnetic material.
  
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  E.g. Floppy disc, hard disc
  

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  It’s a high speed memory and is placed between CPU and main memory.
  
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  The data and instructions stored in it are accessed at a higher speed
  
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  Users cannot access this memory
  
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  It stores data and instructions that are currently to be executed
  

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  Science:-Used by scientists to analyze large quantity of data to analyze the effect of earthquake on buildings and dams for satellite launching and remote controlling.
  
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  Education:-E-Learning is becoming popular. Computers are used as teaching aid in majority of educational institutions.
  
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  Medicine and Health:-Diagnosing the illness to monitoring the patient’s status till his complete recovery.
  

the disease

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  Engineering/Architecture/Manufacturing:-Engineers and architects use the computers for planning, designing and drawing the layouts for house, roads, dams etc.
  
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  Communication:-send and receive e-mails, e-shopping, e-banking, e-commerce, e-learning etc.
  
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  Business and banking:-For numerous administrative purposes, preparing salary bills
  

transactions, publishing etc.

Online business

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  Governments:-Used for weather forecasting, in military, satellite launching and controlling, communication, e-government etc.
  

licenses etc.

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  Entertainment:-Used in music industry, games etc.
  

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  Speed:-The computers can process data at very high speed.
  

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  Accuracy:-The results produced by the computer are very accurate.
  
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  Reliability:-It gives correct and consistent result always even if they are used in adverse conditions.
  
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  Storage capability:-They can store large amounts of data and can be retrieved at any time in fraction of a second.
  
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  Versatility:-They can do variety of jobs based on the instructions given to them.
  
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  Diligence:-They can perform complicated work without any break for days together; even year together without committing any error.
  

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  Non-Intelligent:-It just performs the specified operations.
  

It does not possess any intelligent for analyzing the problem.

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  Inactive:-If the power supply is stopped then the computer ceases to work.
  

a. Memory Management:-Allocating memory to the running program and reallocating when they are terminated

b. Processor Management:-Processing of jobs, deciding on the job scheduling technique and how a job to be processed longs.

Releasing the processor when the jobs are terminated.

c. Device Management:-Allocating the input and output devices to the running processes and reallocating them when processes are terminated.

d. File Mnagement: - Manging the file systems in terms of where the files are stored, their status and memory locations, opening and closing the files, providing access permission to the files.

E.g. of operating system are DOS, UNIX, WINDOWS NT, LINUX
8. Differentiate between WINDOWS and LINUX operating systems.

WINDOWS	LINUX
It is not free of cost	It is available free of cost
It supports GUI(Graphical User Interface)	It does not support GUI(Graphical User Interface)
Networking is possible	Networking is not possible
Requires very high configuration	High configuration is not required
Multi-media facility available	Multi-media support not available
Mobile computing is possible	Mobile computing is not possible
User friendly	Not user friendly

9. What is software? What are the different types of software?

Software is a set of programs which direct the various hardware components.

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  It tells the computer how to accomplish specific tasks, such as word processing or drawing for the user.
  
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  Word processing software for creating text based documents
  
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  Spreadsheet for creating numeric based documents such as budgets
  
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  Database management software for building and manipulating large sets of data
  
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  Presentation program for creating and presenting electronic slide shows
  
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  Graphics program for designing illustrations or manipulating photographs, movies or animation
  
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  Web design tools and web browsers
  
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  Entertainment and education software
  
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  Games
  

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  It is any program that controls the computer hardware or that can be used to maintain the computer in some way so that it runs more effectively
  
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  It has 3 basic types
  

It acts as an interrupt between the hardware application programs and the user

-A network operating system allows computer to communicate and share data across a network while controlling network operations and overseeing the network’s security

-A utility is a program that makes the computer system easier to use or perform highly specified functions