1. Basics of Computers: Classification, Applications, advantages and Limitations.
Chapter 2

2. Classification of computers

3. Computers based on technology
Digital computer:-
using only 0’s and 1’s. 8 bits called a byte.
2. Analog computer:-
values keep changing with time.
Data may be in voltages, frequencies, temperature etc. E.g. Speedometer
3. Hybrid Computer:-It works as digital and analog computers so, it is called analog-digital computer.
Accepts analog signals and converts into digital

4. Computers for organization
Micro Computer:-
It is powerful, easy maintenance, low cost. It is the most common type of PC and commonly called as desktop.
Size is small
Less storage
The length of lines in the range 8-32 bits
E.g.: IBM PC, PS/2
2. Mini computer:-
Capabilities between main frame and micro computers.
So, called mid-range computers. Word length is 32 bits
It is used by small and mid-size business organizations.

5. Computers for organization
3. Main frame computer:-
more powerful than micro computers
word length size is 48,60 or 64 bits
high processing speeds and
can store large amounts of data
used in research organizations, large industries, and large business and government organizations
They need more electricity
E.g.: IBM 3000 series, UNIVAC 1180

6. Computers for organization
4. Super computers:-
used for scientific and engineering applications.
Word length is bit.
They can have very large data bases(uses more data).
They can do one trillion operations per second.
Used in the field of science and defense, designing and launching missiles, weather forecasting, biomedical research
Highest speed
E.g: CRAY-3, HITAC S-300

7. Classification of Memory

8. 1. Primary memory directly used by the CPU . very fast.
Volatile memory: The memory that loses its contents when the computer is turned off.(RAM)
Since the CPU can read or write the data to the memory they called as read-write memories.
Eg. RAM (Random Access Memory): It is temporary memory.
Non volatile memory: store data permanently.
E.g. ROM (Read Only Memory): The information stored in it can be only be read.

9. 2. Secondary Memory
Its is the permanent memory which stores large amount of information for a long time
It’s also called back up memory or auxiliary memory.
E.g. Floppy disc, hard disc, CD drive, DVD drive, DivX drive
Uses Magnetic property, magneto –optical property, optical property, solid state memory

10. 3. Cache memory It’s a high speed memory between CPU and main memory.
higher speed
It stores data and instructions that are currently to be executed

11. Computer Applications
1. Science:-Used by scientists to analyze large quantity of data
to analyze the effect of earthquake
for satellite launching and remote controlling.
2. Education:-E-Learning. Computers are used for teaching

12. Computer Applications
3. Medicine and Health:-
Diagnosing the illness using the computer images and results; they know cause of the disease (scan,x-ray)
4. Engineering/Architecture/Manufacturing:-
for planning, designing and drawing the layouts for house, roads, dams etc.
5. Communication:-
send and receive s, e-shopping, e-banking, e-commerce, e-learning etc.

13. Computer Applications
6. Business and banking:-
For administrative purposes, preparing salary bills.
Used in banking, insurance sectors and marketing
for online payments and transactions, publishing etc.
Online business

14. Computer Applications
7. Governments:-
Used for weather forecasting, in military, satellite launching and controlling, communication, e-government etc.
For police force to search for the information on criminals, crime scenes, driving licenses etc.
8. Entertainment:-
Used in music industry, games etc.
Computer animation and colorful graphics with multimedia effect.

15. Advantages/Merits of computers
1. Speed:- very high speed and Speed is measured in MIPS and BIPS. 2. Accuracy:-The results are very correct. 3. Reliability:-It gives correct and consistent result always 4. Storage capability:- store large amounts of data 5. Versatility:- can do different types of jobs 6. Diligence:- it won’t get tired

16. Disadvantages/De-Merits of computers
Non-Intelligent:-
It just do the given operations.
It does not think.
It does not possess any intelligent for analyzing the problem.
2. Inactive:-
if No power supply, it won’t work.

17. Editors Assembler Compiler Interpreter
to enter program and edit it
converting assembly language instructions to machine instruction by a assembler
high level language translates into machine language
Line by line compilation
Debugging is easy
Debugging is faster
Debugging is slow
E.g.: Turbo C
E.g,: TASM
E.g. TC computer
Eg: BASIC

18. End of Chapter 2