Input and Output Devices-4

Still today we have discussed for different types of the computer hardware devices. Form last few days we are talking on input and output devices which is most important part of the computer hardware. The input or output units of a computer system establish the communication between the system and its users. A large number of input and output units are available in the market. A few of them are discussed in this note.

Most recent trend for data input is towards source data automation. The equipments used for source data automation capture data as a by-product of a business activity thereby completely eliminating manual input of data. Some examples are:

1. Magnetic ink character recognition devices are used by the banking industry to read the account numbers on cheques directly and do the necessary processing.
2. Optical mark recognition devices can sense marks on computer readable papers.

This king of device is used by academic and testing institutions to grade aptitude tests where candidates mark the correct alternatives on a special sheet of paper. These answer sheets are then directly read by the optical mark recognition devices and the information sent to a computer for processing.

Input and Output Devices-2

Terminals have become very popular interactive input and output units. A terminal, when connected to a CPU, sends data and instructions directly into the computer. Terminals can be classified into two types, namely, hard copy terminals and soft copy terminals. A hard copy terminal provides a print out on paper whereas a soft copy terminal provides a visual display on a screen. A soft copy terminal is also known as a CRT (Cathode Ray Tube) terminal.

 

Key-to-tape, key-to-disk and key-to-diskette are stand alone data entry stations. There units usually have a small processor attached to a key board and a visual display unit. The processor checks for the accuracy of data at the time of entry. The screen displays what is being entered. There facilities are highly desirable for a data processing centre. Hence most of the data processing centres are switching over from punched card input to data entry stations.

 

A graphic display terminal displays information in both character and graphic forms. These are extensively used for CAD/CAM (computer aided design/computer aided manufacture) applications.

A potter is used to obtain printed copies of graphic outputs. It is used by architects and designers to produce blueprints of their design on paper.

Talk on interior design

I was planning to have my house renovated. And I want that all my things there are new. I hired and interior designer to design my house.  I told him that I already have a curtain because my sister from the America gave me sets of that.  But my interior designer told me that curtains is an old one, the popular now is the wood blinds.  Since he knew about the designing, I followed him. 

There are several window treatments that are available in the market right now and among them, the wood blinds are probably the most popular of them all. In the past, choices of material, color, and sizes had been limited for blinds.  This is no longer the case now.  My designer goes along with me to a mall to help me choose the best one.

When we are in the mall, we saw different kinds of blind. They are all beautiful.  What we did is we called one representative to give us information of all the blinds which was displayed there. He started showing us the “Holland blinds” and it is also known as roller shades.  It can be pulled down to roll the window blinds.  Then he showed us the “Vertical blinds”, have slats made of plastic, metal or stiffened fabric hanging from a track on its one end. The horizontal slats has a 90 degrees rotation for allowing light to pass or can be fold up to either side of the window or doors. They also called as track blinds.  Then he showed us the last which is the “Venetian blinds” this are slatted blind having either a plastic or metal composition. There are also available slats made of wood pertaining to faux wood blinds, tropical wood blinds or bamboo blinds. The slat width ranges from 50 to 120mm but the most common width is 50mm.

We decided to stop from there because my designer would like to see if which one of there is perfect for my house.