CPU is the processing unit of the computer. Processing is a procedure that transforms raw data into useful information. CPU is attached to the motherboard or system board.
Basically, CPU consists of three sections;
a. Memory Unit (MU)
b. Control Unit (CU)
c. Arithmetic and Logic Unit (ALU)
a. Memory Unit:- Memory unit is the storage unit in the CPU. It holds the data or information which is called for processing. This unit is composed up of very fast registers. It is very small in storage size. Basically, it holds intermediate data during processing.
b. Control unit :- It controls all the units in the computer system. It acts as a traffic that directs the flow of data to various portions at most appropriate time.
C. Arithmetic and logic Unit : All arithmetic and logical operations are performed by this unit. Arithmetic operations include addition, subtraction, multiplication and division. Logical operation involves comparison of two or more variables or expression.
Tuesday, May 17, 2011
Wednesday, April 20, 2011
Troubleshooting, Causes and their Solutions of computer (Point Wise)
1. Problem : No display in computer screen :-
Potential Causes :
a) Loose connection of monitor cable with VGA card.
b) Display card not fixed properly on expansion slot.
c) RAM chips not fixed on memory slot.
d) CPU not fixed on CPU socket.
e) Resolution of monitor is set up in very high resolution, which is not supported by monitor such as 1024 × 1200 in windows 95’ 98’ platform.
f) Display card may be damage.
g) SMPS does not supply accurate power.
h) May be problem in monitor.
i) Motherboard may defective.
j) Reverse connection of data cable on HDD.
k) Monitor adjustment.
Potential Solution :
i) Connect the monitor cable on display card with properly.
ii) Fix properly your display card on expansion slot.
iii) Fix properly RAM on RAM slot.
iv) Fix CPU on CPU socket and check display.
v) Start your computer on safe mode pressing f8 on starting phase and reduce the window resolution (recommended 800 × 600)
vi) Change display card and check display.
vii) Change SMPS and check for display.
viii) Check display by changing other fine monitor.
ix) Change other fine motherboard and check display.
x) Check HDD cable and change cable connection.
xi) Adjust brightness and contrast button on monitor.
2. Problem : Computer restart itself frequently :
Potential Causes :
i) SMPS does not regulate voltage properly.
ii) May be the problem of voltage fluctuation of our electricity system.
iii) Hard disk is full by data or no free space on HDD.
iv) CPU fan is not working properly.
v) Processor may be damage.
vi) Memory problem.
vii) OS problem.
viii) Virus problem.
ix) Power supply (SMPS) problem.
x) IDE drive p[problem
xi) Motherboard problem
Potential Soultion :
i) Check SMPS power by multi meter.
ii) Use volt guard and UPS.
iii) Delete unnecessary data from hard disk to get free space.
iv) Change CPU cooler fan.
v) Change other CPU.
vi) Check and replace memory.
vii) Repair OS or, clean pre-installed OS.
viii) Scan PC thoroughly and clean or, remove virus and spyware.
ix) Check and replace SMPS.
x) Check one by one IDE drives and replace it.
xi) Check and replace motherboard.
3. Problem : Computer Slow :
Potential Causes :
i) Not enough memory for your program.
ii) Insufficient free disk space in HDD.
iii) Due to virus infection.
iv) Lower speed of CPU.
v) Several programs are running at same time.
vi) Lots of application kept in start up.
vii) Cache memory disabled in BIOS setup.
viii) Low video memory in display card.
Potential Solution :
i) Upgrade the memory.
ii) Delete unnecessary files or change other hard disk.
iii) Scan HDD by latest anti virus program.
iv) Upgrade the latest CPU.
v) Do not open several program at the same time.
vi) Remove the program from startup.
vii) Enable cache memory in BIOS setup.
viii) Use fine display card.
4. Problem : Not clear display :
Potential Causes :
i) Improper installation of display card driver.
ii) High resolution, which is not supported by monitor.
Potential Solution :
i) Reinstall the display driver software.
ii) Restart on safe mode and set resolution
5. Problem : Frequently hang the computer :
Potential Causes :
i) Improper BIOS setting.
ii) Virus infection on computer program.
iii) May be memory mismatch.
iv) Conflict on one device with other device.
v) Improper power output from power supply.
vi) Improper installation of drivers of any device.
vii) Insufficient memory.
viii) Not enough free space on HDD.
ix) CPU fan not working properly.
x) Motherboard may be defective.
xi) Not compatible peripherals with motherboard such as sound card, display card, modem and so on.
xii) Mismatch of RAM and display card.
xiii) Corrupted any file of program or installed improperly.
xiv) Bad sector found on hard disk.
xv) Some game create such problem.
xvi) May be mouse and keyboard defective.
xvii) Desktop resolution is higher than supported by your computer.
Potential Solution :
i) Set all option as properly on BIOS setup.
ii) Scan your all drive by latest antivirus.
iii) Use same type of memory.
iv) Check device manager on the property of My Computer.
v) Change or repair power supply unit.
vi) Install the proper driver software of device.
vii) Upgrade memory unit.
viii) Delete unnecessary file to increase free space on HDD.
ix) Change CPU fan.
x) Change your motherboard.
xi) Use compatible card.
xii) Use same type of memory.
xiii) Reinstall the program properly.
xiv) Try to remove the bad sector by any program or change other hard disk.
xv) Remove those game and program. Change keyboard and mouse.
xvi) Change that setting in lower order such as 600 × 800 pixels.
6. Problem: Unable to load windows or hanging the system during windows startup.
Potential Causes:
i) HDD problem
ii) NTLDR is missing
iii) Corrupt boot record or Master Boot Record
Potential Solution: Use recover console options.
i) Enter into the BIOS setting.
ii) Choose CD as a first boot device.
iii) Insert windows XP CD in Cd drive.
iv) Pres any key to start from CD.
v) Press R for recover console option.
vi) Type administrator option (if any) and press Enter key.
vii) Choose 1 (if windows in C drive) or, choose 2 (if windows in D drive)
viii) Then you will get C:\windows>
ix) Type CHKDSK to check and repair disk.
x) Type EXIT to exit from recover console.
xi) Now, choose hard disk as a 1st boot device from BIOS setting.
For NTLDR is missing or Boot Record or Master Boot Record corruption problem,
i) Type FIXMBR or FIXBOOT in the C:\windows>prompt
ii) Type EXIT to exit from recover console.
7. Problem: Beep Sound during booting process
Potential Causes:
i) No memory in place or unseated memory in the place.
ii) Defected memory may be inserted.
Potential Causes:
i) Re-insert the memory in place.
ii) Replace memory
8. Problem :- Continuous long beep sound when switch ON the computer and no display.
Potential Causes :
* RAM do not fix properly on RAM slot.
* Motherboard may be damage.
* Display card does not fixed properly.
* Display card may be damage.
Potential Solution :
* Fix RAM on RAM slot and restart.
* Change motherboard and restart.
* Check and fix properly.
* Change display card and check display.
9. Problem : Loud sound hearing while booting process.
Potential Causes:
* Processor is not fixed in its slot properly.
Potential Solution :
* Pull out the processor and reinsert in the slot.
10. Problem : Hard disk Fail
Potential Causes :
* Data Cable not connected properly.
* Data cable connected in reverse order.
* Not connected power cable on HDD.
* SMPS does not supply required voltage.
* Improper setting in BIOS setup for HDD.
* Improper jumper setting on HDD for Master and slave.
* Hard disk may be damage.
Potential Solutions :
* Check data cable and restart computer.
* Plug the data cable on proper direction.
* Plug the power connector on HDD properly.
* Check power voltage on SMPS (5V or 12V).
* Choose proper setting on BIOS setup.
* Check and fix jumper setting.
* If hard disk is damage, it produces some unusual sound from computer. Replace it.
11. Problem : Mouse Hang
Potential Causes :
* Conflict the port setting.
* Not properly connected in Motherboard.
* Dust in mouse ball.
* Mouse may be damaged.
Potential Solutions :
* Choose empty port for mouse.
* Connected properly in Motherboard.
* Clean the mouse ball and its housing.
* Change other fine mouse.
12. Problem : No power when switch on the computer
Potential Causes :
* Mismatch the power cable.
* Power ON button is defective.
* SMPS may be damaged.
Potential Solutions :
* Connect the power cable as properly.
* Check and repair power switch.
* Repair SMPS.
13. Problem : Press F1 to continue, at the time of booting.
Potential Causes :
* Improper of CMOS setting.
Potential Solution :
* Choose proper option on CMOS setting.
14. Problem : Window shutdown frequently
Potential Causes :
* Virus Infection
* Corruption of windows files
* Mishandling of CMOS setting
* HDD defective.
Potential Solution :
* Scan HDD with latest anti virus program.
* Reinstall windows.
* CMOS setup properly.
* Change new hard disk.
15. Problem : Rough colour in Monitor
Potential Causes :
* Pin in monitor cable may be defective.
* Display card may be damage.
* Incompatibility of display card.
* Monitor may be damage.
* Magnetic attraction to another magnetic device such as speaker.
* Not choosing high colour.
Potential Solutions :
* Check monitor cable pin.
* Change display card.
* Use compatible display card.
* Change or repair monitor.
* keep these items little bit far from monitor.
* Choose high colour setting from display properties.
16. Problem : Modem does not work properly.
Potential Causes :
* Modem is not connected properly.
* Due to conflict in COM ports.
* Modem driver software not installed properly.
* Conflict on I/O address, port, with other device.
Potential Solutions :
* Connect Modem properly.
* Configure the COM ports properly for modem and other device such as mouse.
* Remove and reinstall the modem driver.
* Removing the confliction by changing IRQ and I/O adress.
Potential Causes :
a) Loose connection of monitor cable with VGA card.
b) Display card not fixed properly on expansion slot.
c) RAM chips not fixed on memory slot.
d) CPU not fixed on CPU socket.
e) Resolution of monitor is set up in very high resolution, which is not supported by monitor such as 1024 × 1200 in windows 95’ 98’ platform.
f) Display card may be damage.
g) SMPS does not supply accurate power.
h) May be problem in monitor.
i) Motherboard may defective.
j) Reverse connection of data cable on HDD.
k) Monitor adjustment.
Potential Solution :
i) Connect the monitor cable on display card with properly.
ii) Fix properly your display card on expansion slot.
iii) Fix properly RAM on RAM slot.
iv) Fix CPU on CPU socket and check display.
v) Start your computer on safe mode pressing f8 on starting phase and reduce the window resolution (recommended 800 × 600)
vi) Change display card and check display.
vii) Change SMPS and check for display.
viii) Check display by changing other fine monitor.
ix) Change other fine motherboard and check display.
x) Check HDD cable and change cable connection.
xi) Adjust brightness and contrast button on monitor.
2. Problem : Computer restart itself frequently :
Potential Causes :
i) SMPS does not regulate voltage properly.
ii) May be the problem of voltage fluctuation of our electricity system.
iii) Hard disk is full by data or no free space on HDD.
iv) CPU fan is not working properly.
v) Processor may be damage.
vi) Memory problem.
vii) OS problem.
viii) Virus problem.
ix) Power supply (SMPS) problem.
x) IDE drive p[problem
xi) Motherboard problem
Potential Soultion :
i) Check SMPS power by multi meter.
ii) Use volt guard and UPS.
iii) Delete unnecessary data from hard disk to get free space.
iv) Change CPU cooler fan.
v) Change other CPU.
vi) Check and replace memory.
vii) Repair OS or, clean pre-installed OS.
viii) Scan PC thoroughly and clean or, remove virus and spyware.
ix) Check and replace SMPS.
x) Check one by one IDE drives and replace it.
xi) Check and replace motherboard.
3. Problem : Computer Slow :
Potential Causes :
i) Not enough memory for your program.
ii) Insufficient free disk space in HDD.
iii) Due to virus infection.
iv) Lower speed of CPU.
v) Several programs are running at same time.
vi) Lots of application kept in start up.
vii) Cache memory disabled in BIOS setup.
viii) Low video memory in display card.
Potential Solution :
i) Upgrade the memory.
ii) Delete unnecessary files or change other hard disk.
iii) Scan HDD by latest anti virus program.
iv) Upgrade the latest CPU.
v) Do not open several program at the same time.
vi) Remove the program from startup.
vii) Enable cache memory in BIOS setup.
viii) Use fine display card.
4. Problem : Not clear display :
Potential Causes :
i) Improper installation of display card driver.
ii) High resolution, which is not supported by monitor.
Potential Solution :
i) Reinstall the display driver software.
ii) Restart on safe mode and set resolution
5. Problem : Frequently hang the computer :
Potential Causes :
i) Improper BIOS setting.
ii) Virus infection on computer program.
iii) May be memory mismatch.
iv) Conflict on one device with other device.
v) Improper power output from power supply.
vi) Improper installation of drivers of any device.
vii) Insufficient memory.
viii) Not enough free space on HDD.
ix) CPU fan not working properly.
x) Motherboard may be defective.
xi) Not compatible peripherals with motherboard such as sound card, display card, modem and so on.
xii) Mismatch of RAM and display card.
xiii) Corrupted any file of program or installed improperly.
xiv) Bad sector found on hard disk.
xv) Some game create such problem.
xvi) May be mouse and keyboard defective.
xvii) Desktop resolution is higher than supported by your computer.
Potential Solution :
i) Set all option as properly on BIOS setup.
ii) Scan your all drive by latest antivirus.
iii) Use same type of memory.
iv) Check device manager on the property of My Computer.
v) Change or repair power supply unit.
vi) Install the proper driver software of device.
vii) Upgrade memory unit.
viii) Delete unnecessary file to increase free space on HDD.
ix) Change CPU fan.
x) Change your motherboard.
xi) Use compatible card.
xii) Use same type of memory.
xiii) Reinstall the program properly.
xiv) Try to remove the bad sector by any program or change other hard disk.
xv) Remove those game and program. Change keyboard and mouse.
xvi) Change that setting in lower order such as 600 × 800 pixels.
6. Problem: Unable to load windows or hanging the system during windows startup.
Potential Causes:
i) HDD problem
ii) NTLDR is missing
iii) Corrupt boot record or Master Boot Record
Potential Solution: Use recover console options.
i) Enter into the BIOS setting.
ii) Choose CD as a first boot device.
iii) Insert windows XP CD in Cd drive.
iv) Pres any key to start from CD.
v) Press R for recover console option.
vi) Type administrator option (if any) and press Enter key.
vii) Choose 1 (if windows in C drive) or, choose 2 (if windows in D drive)
viii) Then you will get C:\windows>
ix) Type CHKDSK to check and repair disk.
x) Type EXIT to exit from recover console.
xi) Now, choose hard disk as a 1st boot device from BIOS setting.
For NTLDR is missing or Boot Record or Master Boot Record corruption problem,
i) Type FIXMBR or FIXBOOT in the C:\windows>prompt
ii) Type EXIT to exit from recover console.
7. Problem: Beep Sound during booting process
Potential Causes:
i) No memory in place or unseated memory in the place.
ii) Defected memory may be inserted.
Potential Causes:
i) Re-insert the memory in place.
ii) Replace memory
8. Problem :- Continuous long beep sound when switch ON the computer and no display.
Potential Causes :
* RAM do not fix properly on RAM slot.
* Motherboard may be damage.
* Display card does not fixed properly.
* Display card may be damage.
Potential Solution :
* Fix RAM on RAM slot and restart.
* Change motherboard and restart.
* Check and fix properly.
* Change display card and check display.
9. Problem : Loud sound hearing while booting process.
Potential Causes:
* Processor is not fixed in its slot properly.
Potential Solution :
* Pull out the processor and reinsert in the slot.
10. Problem : Hard disk Fail
Potential Causes :
* Data Cable not connected properly.
* Data cable connected in reverse order.
* Not connected power cable on HDD.
* SMPS does not supply required voltage.
* Improper setting in BIOS setup for HDD.
* Improper jumper setting on HDD for Master and slave.
* Hard disk may be damage.
Potential Solutions :
* Check data cable and restart computer.
* Plug the data cable on proper direction.
* Plug the power connector on HDD properly.
* Check power voltage on SMPS (5V or 12V).
* Choose proper setting on BIOS setup.
* Check and fix jumper setting.
* If hard disk is damage, it produces some unusual sound from computer. Replace it.
11. Problem : Mouse Hang
Potential Causes :
* Conflict the port setting.
* Not properly connected in Motherboard.
* Dust in mouse ball.
* Mouse may be damaged.
Potential Solutions :
* Choose empty port for mouse.
* Connected properly in Motherboard.
* Clean the mouse ball and its housing.
* Change other fine mouse.
12. Problem : No power when switch on the computer
Potential Causes :
* Mismatch the power cable.
* Power ON button is defective.
* SMPS may be damaged.
Potential Solutions :
* Connect the power cable as properly.
* Check and repair power switch.
* Repair SMPS.
13. Problem : Press F1 to continue, at the time of booting.
Potential Causes :
* Improper of CMOS setting.
Potential Solution :
* Choose proper option on CMOS setting.
14. Problem : Window shutdown frequently
Potential Causes :
* Virus Infection
* Corruption of windows files
* Mishandling of CMOS setting
* HDD defective.
Potential Solution :
* Scan HDD with latest anti virus program.
* Reinstall windows.
* CMOS setup properly.
* Change new hard disk.
15. Problem : Rough colour in Monitor
Potential Causes :
* Pin in monitor cable may be defective.
* Display card may be damage.
* Incompatibility of display card.
* Monitor may be damage.
* Magnetic attraction to another magnetic device such as speaker.
* Not choosing high colour.
Potential Solutions :
* Check monitor cable pin.
* Change display card.
* Use compatible display card.
* Change or repair monitor.
* keep these items little bit far from monitor.
* Choose high colour setting from display properties.
16. Problem : Modem does not work properly.
Potential Causes :
* Modem is not connected properly.
* Due to conflict in COM ports.
* Modem driver software not installed properly.
* Conflict on I/O address, port, with other device.
Potential Solutions :
* Connect Modem properly.
* Configure the COM ports properly for modem and other device such as mouse.
* Remove and reinstall the modem driver.
* Removing the confliction by changing IRQ and I/O adress.
Tuesday, April 19, 2011
Different generations of computers
The advancement in electronic technology paved the way for improvement in design and development of computers. As a result, many more computers were developed thereafter. Major developments led to better speed, higher storage capacities and reduced cost of computers. On the basis of the kind of 'Processor' they use, there are five generations of computers. Let us study the generation-wise development in computer technologies.
First generation (1946-1958)
The first generation of computes were developed during the period of 1946 to 1958. They used vacuum tubes or values as their basic electronic components. The vacuum was developed by Lee Deforest.
The characteristics of the first generation computers are :
a. First generation computers were based on vacuum tubes.
b. They were very large in size.
c. They used to produce large amount of heat.
d. They were unreliable.
e. Machine language was used for programming.
f. They were difficult to program and use.
Some of the first generation computers are ENIAC, EDVAC,EDSAC and UNIVAC.
Second generation (1959-1964)
The second generation computers were developed during 1959 to 1964. The second generation of computers emerged with the development of transistors. The transistor was invented by three scientists. J. Bardeen, H.W. Brattain and W. Shockley in 1947.
The characteristics of the second generation computers are :
a. Transistors were used in place of vacuum tubes.
b. They were smaller in comparison with the first generation computers.
c. They generated less heat and were less prone to failure.
d. They look comparatively less computational time.
e. They required air conditioning.
f. Assembly language was used for programming.
Some of the second generation computers are IBM 7000, NCR 304, IBM 650, IBM 1401, ATLAS and MARK-III.
Third generation (1965-1974)
The third generation computers were developed during 1965-1974. The third generation computers emerged with the development of IC (Integrated Circuit). IC was invented by Robert Noyce and Jack Kilby. Ic is a single component containing a number of transistors.
The characteristics of third generation computers are :
a. Third generation computers used integrated circuits instead of transistor.
b. They were smaller in size and cheaper in comparison with the second generation computers.
c. They reduced computational time and had low maintenance cost.
d. High level languages such as COBOL (Common Busines Oriented Language), ForTran (Formula Transalation), BASIC (Begginers All purpose Symbolic Instructionv Code) were developed.
e. Input/Output devices became more sophisticated.
Some of the third generation computers are PDP-8, PDP-11, ICL 2900, IBM 360 and IBM 370.
First generation (1946-1958)
The first generation of computes were developed during the period of 1946 to 1958. They used vacuum tubes or values as their basic electronic components. The vacuum was developed by Lee Deforest.
The characteristics of the first generation computers are :
a. First generation computers were based on vacuum tubes.
b. They were very large in size.
c. They used to produce large amount of heat.
d. They were unreliable.
e. Machine language was used for programming.
f. They were difficult to program and use.
Some of the first generation computers are ENIAC, EDVAC,EDSAC and UNIVAC.
Second generation (1959-1964)
The second generation computers were developed during 1959 to 1964. The second generation of computers emerged with the development of transistors. The transistor was invented by three scientists. J. Bardeen, H.W. Brattain and W. Shockley in 1947.
The characteristics of the second generation computers are :
a. Transistors were used in place of vacuum tubes.
b. They were smaller in comparison with the first generation computers.
c. They generated less heat and were less prone to failure.
d. They look comparatively less computational time.
e. They required air conditioning.
f. Assembly language was used for programming.
Some of the second generation computers are IBM 7000, NCR 304, IBM 650, IBM 1401, ATLAS and MARK-III.
Third generation (1965-1974)
The third generation computers were developed during 1965-1974. The third generation computers emerged with the development of IC (Integrated Circuit). IC was invented by Robert Noyce and Jack Kilby. Ic is a single component containing a number of transistors.
The characteristics of third generation computers are :
a. Third generation computers used integrated circuits instead of transistor.
b. They were smaller in size and cheaper in comparison with the second generation computers.
c. They reduced computational time and had low maintenance cost.
d. High level languages such as COBOL (Common Busines Oriented Language), ForTran (Formula Transalation), BASIC (Begginers All purpose Symbolic Instructionv Code) were developed.
e. Input/Output devices became more sophisticated.
Some of the third generation computers are PDP-8, PDP-11, ICL 2900, IBM 360 and IBM 370.
Monday, April 18, 2011
Parts Of Computer
a) Power supply (SMPS-Switch Mode Power Supply):
Generally, at the backside of the CPU box, controls power for all CPU box (Casing)
b) I/O devices:
Is known as input & output devices. (Keyboard, mouse, scanner, digital/ web Camera are input and Monitor, printer, speaker are output devices)
c) Processor - CPU-Central Processing unit:
The CPU is the heart of the computer system. CPU is the most complex computer system component, responsible for directing most of the computer activities based on the instruction provided. Is the most important part of the computer this could be called the brain of a computer.
It has two main parts:
(a) CU-Control Unit
To take stored instructions in sequence, one at a time. To interpret each instruction and prompt its execution by one of the units like input, output, storage or ALU.
(b) ALU-Arithmetic And Logic Unit
To carry out calculations and comparisons based on the instructions.
d) Motherboard
Motherboard is a main board, which is made-up by printed board circuit. In a computer, the necessary electronic components are mounted on a piece of fiberglass board, known as motherboard, which is held inside the CPU box.
e) Memory devices
i) Primary memory
(1) ROM:
ROM (Read Only Memory) chips stores the programs and data at the time of manufacturing a motherboard. ROM is generally called permanent memory. The data ad programs once written are not lost. This is achieved by storing the information into the ROM at the manufacturing stage. The data remain in ROM even when power is switched off. Information can only be read from ROM (of course randomly) it cannot be written into information that never needs to be altered, or that which should be protected form accidental erasure by the user is stored here. For example, the start-up instructions requi4red by the computer are stored in ROM. The program written on the ROM is also called as firmware.
(2) RAM
RAM (Random Access Memory/ Read Write Memory) is used to store programs and data in running computer as a data carrier. The read and write memory of a computer is know as RAM. The users of the computer can write information into RAM, and read information form (RAM) The data and programs entered by the user are stored into RAM. it has the disadvantage it is volatile (i.e the contains of the memory vanish of get erased as the power to the computer is switched off. RAM is available in the form of chip, which constitutes the main or primary memory of the Microcomputers. The storing capacity of RAM is measured in bytes. RAM chips are available in the market with different memory capacity ranging from 4MB, 8MB, 16MB, 32MB, 64MB, 128MB, 256MB, 512MB, 1024MB/(1GB) etc.
ii) Secondary memory
(1) Floppy disk drive
The floppy disk drive of the computer is used to store data or retrieve data from a floppy disk. Floppy: disk are commonly used as secondary and backup storage media in micro computers. They are popularly called diskettes. These diskettes are very thin and flexible and hence, they are called floppy. They are small convenient and inexpensive. They are removable disks .A floppy disk can be inserted into the disk drive when needed. The Physical size are 8”, 5.25”, 3.5”.
(2) Hard disk drive- HDD
The hard disk drive with its hard disk is permanent storing device, which can hold large programs and tremendous amount of information. Hard disks are commonly used as secondary storage media in microcomputer and large computer. Hard disks made of metallic disk coated with metallic side on the both sides. The hard disks are permanently fixed in a drive unit in case of microcomputer. The disk puck is contained in an airtight dust-fee contain. The read write read and access machines are also sealed with the disks. The sped of rotation is about 3600 rpm (re-pollution per minute). The hard disks are available in different sizes. 8 inch, 5.25 inch. It does not make physical contact with the disk surface.This disk always inside the CPU boxes. It storage large volume of information some hard capacities are 630 MB. 1 GB, 2 GB, 8 GB, 10 GB, 20 GB, 40 GB, 40GB, 80GB etc.
Reading and writing:- The hard disk also has a read and writes head that moves ever the desired track to head data from of write data into the disk. A mentioned above the read and write head along with the access arm does not physically touch the disk surface, it floats above the surface of the disk and defaults the data (magnetized data) A hard disk can store much more data than the floppy disk of the same size A 8 inch hard disk could store 20MB where as the same size floppy disk could only 1MB. The hard disks are useful in word-processing and other applications where a large volume of files of data is to be kept.
(3) Compact Disk Drive
The most popular and least expensive type of optical disk is compact disk. CD drive is also an important data storage device known as optical disk drive. The manufactures themselves write data on CD-ROM the CD-ROM is made up of resin. It is coated with a material (eg aluminums), which will change when a high intensity laser beam is focused on it.
Types Of Optical Disk:
1. CD-ROM (Compact Disk-Read Only Memory):- it is an optical ROM which enables prerecorded data to be read. A laser beam is used to write into or read. from CD-ROM. The CD-ROME has very high storing capacity. The read and write head of a CD-ROM drive unit does not touch the disk surface; there is no risk, disk wear of head crash.
2. CD-RW:- (Compact Disk Read Write) While writing high intensity laser beam from as tiny pit along the surface, which represent binary bit 1 absence of bit represents bit 0 while reading CD-ROM, the reflected laser is sensed by photo diode (light sensitive semiconductor dived) The intensity of laser beam changes when the beam encounters pit ie. A pit spreads light so that photo diode little reflected light but the surface with out reflects enough light to the photo diode.
3. Combo Drive: DVD read only and CD Read and Write both.
4. DVD-RW: CD Read, Write & DVD-Read Write both.
Advantages of CD-ROM
CD-ROM has very high storing capacity
They are relatively less expensive.
They have a long life (at least 20 years)
They are comparatively reliable.
CD-ROM can be removed from the drive.
Generally, at the backside of the CPU box, controls power for all CPU box (Casing)
b) I/O devices:
Is known as input & output devices. (Keyboard, mouse, scanner, digital/ web Camera are input and Monitor, printer, speaker are output devices)
c) Processor - CPU-Central Processing unit:
The CPU is the heart of the computer system. CPU is the most complex computer system component, responsible for directing most of the computer activities based on the instruction provided. Is the most important part of the computer this could be called the brain of a computer.
It has two main parts:
(a) CU-Control Unit
To take stored instructions in sequence, one at a time. To interpret each instruction and prompt its execution by one of the units like input, output, storage or ALU.
(b) ALU-Arithmetic And Logic Unit
To carry out calculations and comparisons based on the instructions.
d) Motherboard
Motherboard is a main board, which is made-up by printed board circuit. In a computer, the necessary electronic components are mounted on a piece of fiberglass board, known as motherboard, which is held inside the CPU box.
e) Memory devices
i) Primary memory
(1) ROM:
ROM (Read Only Memory) chips stores the programs and data at the time of manufacturing a motherboard. ROM is generally called permanent memory. The data ad programs once written are not lost. This is achieved by storing the information into the ROM at the manufacturing stage. The data remain in ROM even when power is switched off. Information can only be read from ROM (of course randomly) it cannot be written into information that never needs to be altered, or that which should be protected form accidental erasure by the user is stored here. For example, the start-up instructions requi4red by the computer are stored in ROM. The program written on the ROM is also called as firmware.
(2) RAM
RAM (Random Access Memory/ Read Write Memory) is used to store programs and data in running computer as a data carrier. The read and write memory of a computer is know as RAM. The users of the computer can write information into RAM, and read information form (RAM) The data and programs entered by the user are stored into RAM. it has the disadvantage it is volatile (i.e the contains of the memory vanish of get erased as the power to the computer is switched off. RAM is available in the form of chip, which constitutes the main or primary memory of the Microcomputers. The storing capacity of RAM is measured in bytes. RAM chips are available in the market with different memory capacity ranging from 4MB, 8MB, 16MB, 32MB, 64MB, 128MB, 256MB, 512MB, 1024MB/(1GB) etc.
ii) Secondary memory
(1) Floppy disk drive
The floppy disk drive of the computer is used to store data or retrieve data from a floppy disk. Floppy: disk are commonly used as secondary and backup storage media in micro computers. They are popularly called diskettes. These diskettes are very thin and flexible and hence, they are called floppy. They are small convenient and inexpensive. They are removable disks .A floppy disk can be inserted into the disk drive when needed. The Physical size are 8”, 5.25”, 3.5”.
(2) Hard disk drive- HDD
The hard disk drive with its hard disk is permanent storing device, which can hold large programs and tremendous amount of information. Hard disks are commonly used as secondary storage media in microcomputer and large computer. Hard disks made of metallic disk coated with metallic side on the both sides. The hard disks are permanently fixed in a drive unit in case of microcomputer. The disk puck is contained in an airtight dust-fee contain. The read write read and access machines are also sealed with the disks. The sped of rotation is about 3600 rpm (re-pollution per minute). The hard disks are available in different sizes. 8 inch, 5.25 inch. It does not make physical contact with the disk surface.This disk always inside the CPU boxes. It storage large volume of information some hard capacities are 630 MB. 1 GB, 2 GB, 8 GB, 10 GB, 20 GB, 40 GB, 40GB, 80GB etc.
Reading and writing:- The hard disk also has a read and writes head that moves ever the desired track to head data from of write data into the disk. A mentioned above the read and write head along with the access arm does not physically touch the disk surface, it floats above the surface of the disk and defaults the data (magnetized data) A hard disk can store much more data than the floppy disk of the same size A 8 inch hard disk could store 20MB where as the same size floppy disk could only 1MB. The hard disks are useful in word-processing and other applications where a large volume of files of data is to be kept.
(3) Compact Disk Drive
The most popular and least expensive type of optical disk is compact disk. CD drive is also an important data storage device known as optical disk drive. The manufactures themselves write data on CD-ROM the CD-ROM is made up of resin. It is coated with a material (eg aluminums), which will change when a high intensity laser beam is focused on it.
Types Of Optical Disk:
1. CD-ROM (Compact Disk-Read Only Memory):- it is an optical ROM which enables prerecorded data to be read. A laser beam is used to write into or read. from CD-ROM. The CD-ROME has very high storing capacity. The read and write head of a CD-ROM drive unit does not touch the disk surface; there is no risk, disk wear of head crash.
2. CD-RW:- (Compact Disk Read Write) While writing high intensity laser beam from as tiny pit along the surface, which represent binary bit 1 absence of bit represents bit 0 while reading CD-ROM, the reflected laser is sensed by photo diode (light sensitive semiconductor dived) The intensity of laser beam changes when the beam encounters pit ie. A pit spreads light so that photo diode little reflected light but the surface with out reflects enough light to the photo diode.
3. Combo Drive: DVD read only and CD Read and Write both.
4. DVD-RW: CD Read, Write & DVD-Read Write both.
Advantages of CD-ROM
CD-ROM has very high storing capacity
They are relatively less expensive.
They have a long life (at least 20 years)
They are comparatively reliable.
CD-ROM can be removed from the drive.
Saturday, April 16, 2011
Software engineering
Introduction :-
Software is not a few term for us. "Software" and "Program" are interchangeablyused to denote the set of instructions that make computer work. But there exits some conceptual difference between them. Programs are generally small and can do simple things; for example program to generate Fibonacci series, program to find the square-root of the given number etc. Softwares are packaged programs. So, a software can contain many programs. For example, microsoft word is a software. Similarly; Windows XP, Microsoft Excel, etc are softwares. But in general terms programs and software can be thought of as the same thing. programs are small software and softwares are large-programs.
Software Engineering :-
We all know that engineering is involved in all construction works. We must prepare detailed maps before we make our house and before a road or water supply pipelines are constructed. The engineering approach defines a systematic steps and methods of doing something such that the desired things are constructed correctly.
We may not know that softwares are also engineered. There is a special field of computer studies called software enginnering. This is relatively a new field of studies as compared to other engineering subjects. Software engineering defies the systematic and scientific approach of developing a software.
Software engineering has defied several approaches of developing a software which known as software development models. Following are some of the models suggested by the software enginneering.
a. Water fall model of software development
b. Prototyping model of software development
c. Spiral model of software development
May what be the model of software development we use, one thing common in all is that, they view software development as a life-cycle model. The word life-cycle denotes that software development is cyclic and iterative. It never ends. The steps we follow in software development iteratively are called steps of software development life cycle.
Software is not a few term for us. "Software" and "Program" are interchangeablyused to denote the set of instructions that make computer work. But there exits some conceptual difference between them. Programs are generally small and can do simple things; for example program to generate Fibonacci series, program to find the square-root of the given number etc. Softwares are packaged programs. So, a software can contain many programs. For example, microsoft word is a software. Similarly; Windows XP, Microsoft Excel, etc are softwares. But in general terms programs and software can be thought of as the same thing. programs are small software and softwares are large-programs.
Software Engineering :-
We all know that engineering is involved in all construction works. We must prepare detailed maps before we make our house and before a road or water supply pipelines are constructed. The engineering approach defines a systematic steps and methods of doing something such that the desired things are constructed correctly.
We may not know that softwares are also engineered. There is a special field of computer studies called software enginnering. This is relatively a new field of studies as compared to other engineering subjects. Software engineering defies the systematic and scientific approach of developing a software.
Software engineering has defied several approaches of developing a software which known as software development models. Following are some of the models suggested by the software enginneering.
a. Water fall model of software development
b. Prototyping model of software development
c. Spiral model of software development
May what be the model of software development we use, one thing common in all is that, they view software development as a life-cycle model. The word life-cycle denotes that software development is cyclic and iterative. It never ends. The steps we follow in software development iteratively are called steps of software development life cycle.
Friday, January 29, 2010
COMPUTER APPLICATION
In 1950's , Computers were very expensive and were only used by large institutions such as governments and universities. The computers were used for calculating the precise time of spacecraft journey or planning the targests of missiles, or processing Census data.
In 1960's, IBM introduced mainframe computers. then, the use of computer increased rapidly in business organizations. But, they were expensive for general use.
After the introduction of PC's (Personal Computers) in 1870's, size as well as price of computer decreased. So, computers became common to small business or home use. Now, computers are used in many areas, such as :
1. BUSINESS :
Computers are the part of the modern society. Modern business can not survive without computers. In business, computers are used to write letters, keep employee records, communicate with the co-workers, prepare budgets and perform many other functions.
2. Medicine and Health Care :
Computers are extensive used in medicine. It is used for diagnosing diseases, monitoring the condition of patients and keeping the necessary records.
Many innovative medical applications use small, special-purpose computers. For example, pacemakers are computers that operate within the human body and help to maintain heart beat.
Also, laboratory tests such as X-RAY, CT-SCAN etc are performed by computers.
3. Education :
Computers have brought revolution in the field of education. Now, computers are used in school and colleges by students, teachers and many others. People use computers in library to read magazines and journals from the computer terminal rather than searching the shelves for paper organizations.
Teachers use computers as a presentation tool, to explain difficult topics more clearly and easily to their students.
Students use computers to develop their computer projects and to do their mathematical problems.
Computer Assisted Learning (CAL) is used by students to improve knowledge of any subject.
In 1960's, IBM introduced mainframe computers. then, the use of computer increased rapidly in business organizations. But, they were expensive for general use.
After the introduction of PC's (Personal Computers) in 1870's, size as well as price of computer decreased. So, computers became common to small business or home use. Now, computers are used in many areas, such as :
1. BUSINESS :
Computers are the part of the modern society. Modern business can not survive without computers. In business, computers are used to write letters, keep employee records, communicate with the co-workers, prepare budgets and perform many other functions.
2. Medicine and Health Care :
Computers are extensive used in medicine. It is used for diagnosing diseases, monitoring the condition of patients and keeping the necessary records.
Many innovative medical applications use small, special-purpose computers. For example, pacemakers are computers that operate within the human body and help to maintain heart beat.
Also, laboratory tests such as X-RAY, CT-SCAN etc are performed by computers.
3. Education :
Computers have brought revolution in the field of education. Now, computers are used in school and colleges by students, teachers and many others. People use computers in library to read magazines and journals from the computer terminal rather than searching the shelves for paper organizations.
Teachers use computers as a presentation tool, to explain difficult topics more clearly and easily to their students.
Students use computers to develop their computer projects and to do their mathematical problems.
Computer Assisted Learning (CAL) is used by students to improve knowledge of any subject.
4. Space Technology :
It would be impossible to explore outer space without computers. Computers are used to make accurate calculations for the spacecraft journey to moon, mars etc. The computer is also used to control the artificial satelites to know the weather patterns in earth. Nowadays, the actual damage due to flood, earthquake, etc. in particular area of earth is analyzed using satelite pictures.
5. Engineering
Engineers use computers to design the model of machines, vehicles, bridges, buildings etc. The design made with computers is more accurate and flexible than the design drawn with paper and pencil.
The design of complex structures such as aeroplanes, satelites etc. is almost impossible without computers.
6. Aviation :
The computer is highly used in aviation. Modern aircrafts include sophisticated computerized instruments so that it can communicate with the ground airport atations, identify the status of its parts, fuel and available location in the atmosphere.
Thus, the use of computer has increased security in aviation.
7. Music and Entertainment :
Computers have become a helpful tool for musicians. It helps them to create various electronic notes. Also, the notes can be converted to music graphs. The composer can create the music of many musical instruments using a special keyboard called MIDI Keyboard.
Computers games are the means of entertainment for people of all ages. Computers are heavily used in entertainment industry i.e. television, theater, films, etc. Films are special visual effects to make the contens real. These effects are possible using computers. Computers have also improved cartooning and animations.
8. The Military :
Military or Defense services use computers massively. the actual development of computers are due to military. In 1946, ENIAC (Electrionic Numerical Integrator and Calculator) was created for the U.S. Army. They used ENIAC for calculating accurate targets of missiles.
Now, military uses more advanced computer technology. They use computers to spy the enemy secrets such as enemy location, enemy numbers and their amount of weapons. they also use a special type of missile called "Smart Bomb" which embeds computer within it.
The design of complex structures such as aeroplanes, satelites etc. is almost impossible without computers.
6. Aviation :
The computer is highly used in aviation. Modern aircrafts include sophisticated computerized instruments so that it can communicate with the ground airport atations, identify the status of its parts, fuel and available location in the atmosphere.
Thus, the use of computer has increased security in aviation.
7. Music and Entertainment :
Computers have become a helpful tool for musicians. It helps them to create various electronic notes. Also, the notes can be converted to music graphs. The composer can create the music of many musical instruments using a special keyboard called MIDI Keyboard.
Computers games are the means of entertainment for people of all ages. Computers are heavily used in entertainment industry i.e. television, theater, films, etc. Films are special visual effects to make the contens real. These effects are possible using computers. Computers have also improved cartooning and animations.
8. The Military :
Military or Defense services use computers massively. the actual development of computers are due to military. In 1946, ENIAC (Electrionic Numerical Integrator and Calculator) was created for the U.S. Army. They used ENIAC for calculating accurate targets of missiles.
Now, military uses more advanced computer technology. They use computers to spy the enemy secrets such as enemy location, enemy numbers and their amount of weapons. they also use a special type of missile called "Smart Bomb" which embeds computer within it.
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