IO devices
IO devices:
To enter information and instructions into a computer for storage or processing and to deliver the processed data to a human operator.
IO module:
Computer connected to other devices.
IO card:
Communication between a information processing system, such as a computer, and outside world.
Monitor:
O/P devices displays information in pictorial form.
Types of monitor:
CRT.
LCD.
CRT:
Cathode ray tube.
Contains millions of tiny red, green, blue phosphor dots that glow when stuck by electron beam that travels across the screen to create visible image.
Electron beam:
Stream of electrons pass through gas or vacuum.
Advantages:
Resolution and Aspect ratio.
Cost.
Motion artifact.
Motion artifact:
Rapidly moving or changing images.
Disadvantages:
Screen shape.
Brightness.
Physical.
LCD:
Liquid crystal display.
Each crystal acts like shutter, either passing or stopping.
Techniques of LCD:
Passive.
Thin film transistor.
Passive:
Less expensive.
Thin film transistor:
Produces image as sharp as CRT but expensive.
Advantages:
Energy efficient, Low power.
Light weight and compact.
Screen sizes are available in various sizes.
Disadvantages:
Imaginary is not good.
Newer technology costs more.
History of Monitor:
Early monitors only capable of displaying a limited information.
Rarely used for output.
Who invented monitor?
Karl Ferdinand Braun in 1905.
Processor:
Responds to and processes the basic instruction of computer.
Functions of Processor:
Fetch.
Decode.
Execute.
Write back.
Components:
ALU.
Processor register.
Control unit.
FPU.
L1 and L2 cache.
ALU:
Performs Arithmetic and logical operations.
Processor register:
Hold instructions and other data.
Supply operand and store result.
CU:
How to respond to instruction.
FPU:
Operations on floating point no's.
Cache:
To store information temporarily.
L1 cache:
Fastest cache.
Small size.
SRAM.
L2 cache:
Accessed data only when not found in L1.
DRAM.
SRAM:
Static Random access memory.
To have data on memory.
DRAM:
Dynamic random access memory.
Loses data when power is removed.
Stores data in capacitor and transistor.
Printer:
Readable representation of graphics or text on paper.
Types of Printer:
Personal printer.
Networked or shared printer.
Virtual printer.
3d printer.
Personal printer:
Designed to support individual user.
6 to 25 pages per minute.
Networked printer:
Shared by many user.
45 to 100 pages per minute.
Virtual printer:
Not connected with physical computer printer.
Document is printing means not printing in paper, saving the document in another format.
3d printing:
Allows the creation of objects in 3 dimensional.
Laser printing:
Producing a good quality material by using a laser.
How it works?
When a document is sent to printer a laser beam "draws" the document on selenium coated drum.
After drum is charged, it is rolled in toner, dry powder type of ink.
Drum in printer:
Transfers the paper.
Toner in printer:
A powder used for printing in text and images.
Inkjet printer:
Produces hard copy by spraying ink on paper good quality images and color.
Difference between Laser and Inkjet printer?
Thermal printer:
In which fine heated pins form characters.
Types of thermal printing:
Direct thermal.
Thermal wax transfer.
Direct thermal:
Prints image by burning dots onto coated paper.
When paper passes over a line of heating element.
Thermal wax transfer:
Wax based ink onto paper.
Thermal print head melts wax based ink from the transfer ribbon on to paper.
When cools wax becomes permanent.
Advantages:
Efficiency.
Mobility.
Less space.
No issues with ribbon.
Disadvantages:
Direct thermal can cost little more.
With sun exposure the labels will fade.
Dot matrix printers:
Impact matrix printer.
Printer can create carbon copy or carbon less copies.
Cannot produce high quality output.
Each dot is produced by tiny metal rod also called wire or pin.
Characteristics:
Speed.
Print quality.
Speed:
Can vary 9 to 24 pins.
24 pins can produce near letter quality type, but still you can see the difference.
Advantages:
Can print carbon copies.
Lowest printing cost per page.
Ink ribbon does not easily dry.
Disadvantages:
Noisy.
Limited quality.
DPI:
Dots per inch.
Measure of printing.
More DPI means clear output.
Does DPI is same for all printers?
Depends on the print head technology it uses.
Examples are Dot matrix 60 to 90 DPI.
Inkjet 300 to 720 DPI.
Laser 600 to 2,400 DPI.
To enter information and instructions into a computer for storage or processing and to deliver the processed data to a human operator.
IO module:
Computer connected to other devices.
IO card:
Communication between a information processing system, such as a computer, and outside world.
Monitor:
O/P devices displays information in pictorial form.
Types of monitor:
CRT.
LCD.
CRT:
Cathode ray tube.
Contains millions of tiny red, green, blue phosphor dots that glow when stuck by electron beam that travels across the screen to create visible image.
Electron beam:
Stream of electrons pass through gas or vacuum.
Advantages:
Resolution and Aspect ratio.
Cost.
Motion artifact.
Motion artifact:
Rapidly moving or changing images.
Disadvantages:
Screen shape.
Brightness.
Physical.
LCD:
Liquid crystal display.
Each crystal acts like shutter, either passing or stopping.
Techniques of LCD:
Passive.
Thin film transistor.
Passive:
Less expensive.
Thin film transistor:
Produces image as sharp as CRT but expensive.
Advantages:
Energy efficient, Low power.
Light weight and compact.
Screen sizes are available in various sizes.
Disadvantages:
Imaginary is not good.
Newer technology costs more.
History of Monitor:
Early monitors only capable of displaying a limited information.
Rarely used for output.
Who invented monitor?
Karl Ferdinand Braun in 1905.
Processor:
Responds to and processes the basic instruction of computer.
Functions of Processor:
Fetch.
Decode.
Execute.
Write back.
Components:
ALU.
Processor register.
Control unit.
FPU.
L1 and L2 cache.
ALU:
Performs Arithmetic and logical operations.
Processor register:
Hold instructions and other data.
Supply operand and store result.
CU:
How to respond to instruction.
FPU:
Operations on floating point no's.
Cache:
To store information temporarily.
L1 cache:
Fastest cache.
Small size.
SRAM.
L2 cache:
Accessed data only when not found in L1.
DRAM.
SRAM:
Static Random access memory.
To have data on memory.
DRAM:
Dynamic random access memory.
Loses data when power is removed.
Stores data in capacitor and transistor.
Printer:
Readable representation of graphics or text on paper.
Types of Printer:
Personal printer.
Networked or shared printer.
Virtual printer.
3d printer.
Personal printer:
Designed to support individual user.
6 to 25 pages per minute.
Networked printer:
Shared by many user.
45 to 100 pages per minute.
Virtual printer:
Not connected with physical computer printer.
Document is printing means not printing in paper, saving the document in another format.
3d printing:
Allows the creation of objects in 3 dimensional.
Laser printing:
Producing a good quality material by using a laser.
How it works?
When a document is sent to printer a laser beam "draws" the document on selenium coated drum.
After drum is charged, it is rolled in toner, dry powder type of ink.
Drum in printer:
Transfers the paper.
Toner in printer:
A powder used for printing in text and images.
Inkjet printer:
Produces hard copy by spraying ink on paper good quality images and color.
Difference between Laser and Inkjet printer?
| Laser | Inkjet |
|---|---|
| Toner. | Uses ink. |
| Geometric shape. | See the images they print as tiny points. |
| No blur. | Possibility of appearing blur due to absorption. |
| More cost for printer. Less cost for toner. | Less cost for printer.More cost for ink. |
Thermal printer:
In which fine heated pins form characters.
Types of thermal printing:
Direct thermal.
Thermal wax transfer.
Direct thermal:
Prints image by burning dots onto coated paper.
When paper passes over a line of heating element.
Thermal wax transfer:
Wax based ink onto paper.
Thermal print head melts wax based ink from the transfer ribbon on to paper.
When cools wax becomes permanent.
Advantages:
Efficiency.
Mobility.
Less space.
No issues with ribbon.
Disadvantages:
Direct thermal can cost little more.
With sun exposure the labels will fade.
Dot matrix printers:
Impact matrix printer.
Printer can create carbon copy or carbon less copies.
Cannot produce high quality output.
Each dot is produced by tiny metal rod also called wire or pin.
Characteristics:
Speed.
Print quality.
Speed:
Can vary 9 to 24 pins.
24 pins can produce near letter quality type, but still you can see the difference.
Advantages:
Can print carbon copies.
Lowest printing cost per page.
Ink ribbon does not easily dry.
Disadvantages:
Noisy.
Limited quality.
DPI:
Dots per inch.
Measure of printing.
More DPI means clear output.
Does DPI is same for all printers?
Depends on the print head technology it uses.
Examples are Dot matrix 60 to 90 DPI.
Inkjet 300 to 720 DPI.
Laser 600 to 2,400 DPI.