Thursday, February 28, 2013

Data Collection and Input

Data Collection and Input

Data Collection and Input

DATA COLLECTION

Data collection means bringing together all the data for an application and getting it ready for processing.

Examples of data collection

1 Bank cheques are sent from branches to a central clearing house. There they are put together for sorting and updating accounts.

2 Application forma for subscriptions to a magazine are sent out to possible customers. Those who want the magazine fill in the for-ms and send them back. Their details are then typed into a computer via a keyboard.

DATA CAPTURE

Data capture means obtaining data for a computer. Usually the term is used in situations where a computer peripheral inputs the data automatically.

Examples of data capture

1- At a particular supermarket checkout there are POS terminals. Each product has a catalogue number that is encoded on a bar code. This can be read using a light pen .

2- An examination candidate does a multiple choice test by marking a card with a pencil in the right places. The card is then read by a mark sensing device attached to a computer.

SOURCE DOCUMENTS AND TURNAROUND DOCUMENTS

A source document is the original piece of paper on which data is written when it is first recorded. A turnaround document is one which is produced as output at one stage of the data processing cycle, has more data added to it, and is then input for further processing.

Example of a source document and a turnaround document

A gas board uses the following system for its customer accounts. When a person becomes a customer he/she has to give details which are recorded on a source document. Using this data the computer prints forms for the meter reader which contain the customer's account number, address and probable usage of gas. These are turnaround documents because the meter reader inserts the meter reading and the forms are then input to the computer and the customer's gas bill is calculated and printed (see Fig3).

DATA PREPARATION

Data preparation is encoding data on to a medium which a computer input device can accept.

Computer Studies-12_03

Fig 3 A meter reading form

Usually the data has been written previously on to a suitable form and is typed by a skilled operator on to the medium, using a special machine with a keyboard.

Example of data preparation

Data is put on to a floppy disc by an operator using a key-to-floppy-disc station.

DATA TRANSMISSION AND COMMUNICATIONS

Data transmission means the sending of data from one place to another.

Data communications is a general term for applications which involve the transmission of data between a user and a computer or between two or more computers.

Examples of data communications

1- Electronic mail . One user of a national computer network can send a letter to another user's 'mailbox', This is in the store of a remote computer. The other user can then read this letter by logging in to the computer with his or her own terminal. The two users may be at opposite ends of the country.

2- A newspaper office in one country can transmit pictures to the newspaper's headquarters in another country. A special scanner is used to do this via the telephone network.

STANDARDIZED INPUT

During data collection, data may be written on to specially prepared data capture forms. The purpose of these may be:

1- To make it clear what data needs to be collected.

2- To make it easy to see what the data is.

3- To standardize the way in which data is recorded.

4- To assist in future filing of the data.

They may be used as:

1- Index cards-cards which can be stored in a drawer or filing cabinet for easy access,

2- Source documents used to prepare data for a computer system.

Examples of data capture forms

1- An index card used in a doctor's surgery to record details of patients, These are for manual filing .

2- A subscription form for a magazine. The applicant has to fill in name, address, title, etc. carefully in small squares, (see Fig. 4).

3- A multiple-choice answer paper.

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fig 4 A membership form