Plotter

Plotter:

A plotter is a computer hardware device much like a printer that is used for printing vector graphics. Instead of toner, plotters use a pen, pencil, marker or other writing tool to draw multiple, continuous lines onto paper rather than a series of dots like a traditional printer. Though once widely used for computer aided design, these devices have more or less been phased out by wide format printers. Plotters are used to produce a hard copy of schematics and other similar applications.

Figure: Plotter

Advantages of plotters:

1. Plotters can work on very large sheets of paper while maintaining high resolution.
2. They can print on a wide variety of flat materials including plywood, aluminum, sheet steel, cardboard, and plastic.
3. Plotters allow the same pattern to be drawn thousands of times without any image degradation.

Disadvantages of plotters:

1. Plotters are quite large when compared to a traditional printer.
2. Plotters are also much more expensive than a traditional printer.

Output Device

Output Device: 

An output device is an electromechanical device, which accepts data from a computer and translates them into a form, which is suitable for use by the users. The two principal kinds of output devices are hard copy, which is printed and softcopy, such as material shown on display screen. Several output devices are available today.

Figure: Output Devices

They can be classified into following categories:

• Printer
• Monitor
• Speaker or Headphone
• Projector
• Plotter, etc. 

Digital Camera

Digital Camera: 

Digital camera is rapidly replacing film-based camera. Once photographs are stored in memory, they are easily transferred to a computer a USB connection. Once saved, the images can be manipulated.

Figure: Digital Camera

Uses of Digital Camera:

1. Digital camera produces photographs for transfer to a computer directory of to print out by connecting directly to a printer.
2. Many digital cameras also allow short video clips to be produced.

Scanner

Scanner: 

Scanner is used to enter information on hard copy into a computer. The most common type is the flat bed which is made up of a glass panel and lid. The hard copy document or photo is scanned by a light source and produces a computer readable image.

Figure: Scanner

Uses of Scanner:

1. Scanners are used to scan in document and convert them into a format for use in various software packages.
2. Old and valuable documents and books can be scanned for records. Also non-digital photographs need to be scanned if they are to be stored on computer.

Magnetic Ink Character Reader (MICR)

Magnetic Ink Character Reader (MICR): 

MICR is the system which can dead characters printed in a special ink. Only certain characters written in a standard front can be read. Those characters are converted into a form that the computer can understand.

Figure: Magnetic Ink Character Reader (MICR)

Uses of MICR:

1. It is primarily used to processing cheques in banking operations.
2. MICR offers greater security than OCR and very reliable, low errors.

Optical Character Reader (OCR)

Optical Character Reader (OCR): 

OCR is the mechanical or electronic translation of scanned images of handwritten, typewritten or printed text into machine encoded text.

Figure: Optical Character Reader (OCR)

Uses of OCR:

1. One of the most recent uses is in the processing of passports and identity cards.
2. It is widely used to convert books and documents into electronic files to computerize a record-keeping system.

Optical Mark Reader (OMR)

Optical Mark Reader (OMR): 

OMR is a special scanning device that can read carefully placed pencil marks on specially designed documents. OMR enables the processing of hundreds or thousands of documents every hour automatically.

Figure: Optical Mark Reader (OMR)

Uses of OMR:

1. OMR device are used to read questionnaires, multiple- choice examination paper and many other types of form where responses are registered in the form of lines or shaded areas.

Barcode reader

Barcode reader: 

Barcode reader is used to read information in the form of the bar code. The readers are usually in the form of a barcode scanner and are often built in to POS terminals in supermarkets.

Figure: Barcode reader

Uses of a Barcode reader: 

1. Barcode scanners are used in supermarkets and other shops where the goods are marked with a barcode; the barcodes are used to give information about the product, which enables automatic stock control, itemized billing etc. to take place.
2. They are used in libraries, to scan both user’s library cards and barcodes on books, in order to keep track of books on loan.

Touchscreen

Touchscreen: 

A touch screen is a video display screen that has been sensitized to receive input from the touch of a finger. The screen is covered with a plastic layer, behind which are invisible beams of infrared light.

Figure: Touchscreen

Uses of Touchscreen: 

1. Touchscreens are used for self-service tall, where the user just touches the screen to select the fuel grade and payment method.
2. Touchscreens are used where selections are made on screen, for example ATMs.

Mouse

Mouse: 

A mouse is a hard movable device that controls the position of the cursor on a screen. It has a box with buttons on the top and a ball on the bottom.
The box is placed on a flat surface, with the user’s hand over it. The ball’s movement on the surface causes the cursor.

Figure: PC mouse

Uses of mouse:

1. Mouse can be used for opening, closing and minimizing software.
2. They are very useful when editing images.
3. Mouse are used for controlling the position of a pointer on the screen to allow selection from a menu or selecting an icon and for scrolling up and down or left to night.

Terminals and Types: DUMB, SMART & INTELLIGENT

Terminals: 

A terminals is an input device that consists of a keyboard, a video display screen and a communications line to a mainframe computer system.

Figure: Example of terminal

Terminals are three types:

1. DUMB: A dumb terminal can be used only to input data to and receive information from a computer system. That is, it can’t do any processing on its own. 

Keyboard

Keyboard: 

The keyboard is the most widely used input device. They allow data entry into a computer system by pressing a set of keys (labeled button), which are neatly mounted on a keyboard, which is connected to the computer system.

Figure: keyboard

Uses of keyboard:

1. Keyboards are used to input data in application software.
2. They are also used for typing in commands to the computer.

Input Device

Input device: 

An input device is an electromechanical device, which accepts data from outside world and translates them into a form suitable for computer processing. Several input devices are available today.

Figure: Input Devices

They can be classified into following categories:

• Keyboard
• Terminals
• Mouse
• Touch Screen
• Barcode reader
• Optical Mark Reader (OMR)
• Optical Character Reader (OCR)
• Magnetic Ink Character Reader (MICR)
• Scanner
• Digital Camera, etc. 

Types of hardware/ components of computer

Hardware:

The mechanical devices that make up the computer are called hardware. Hardware is any part of the computer that we can touch. Computers hardware consists of interconnected electronic devices that we can use to control the computers operation input and output.

Computer hardware can be divided into five categories:

• Input hardware
• Processing hardware
• Storage hardware
• Output hardware
• Communication hardware

Input hardware:

The function of input hardware is to collect data and convert it into   suitable from for computer processing. Common input devices are the keyboard and the mouse.

Parity Bit, Parity Check and Variants of Parity Bit: Even Parity bit & Odd Parity bit

Parity Bit:

An extra bit added to a string of bits, which enables the computer to detect internal errors in the transmission of binary data is called parity bit.

Parity Check: 

Parity is a special type of method in order to recover single bit error. An additional bit is added in the leftmost position of number sequences.

There are two variants of parity bit:

1. Even parity bit
2. Odd parity bit