Data - Overview

[data is stored in binary]

"Raw - unprocessed facts"

That which makes the computer useful to us as individuals,
Distinguishes our computer from others.
Is the prime reason WHY we have a computer.
Cannot be used to make a decision.

Data and the storage of is a fundamental component of an information system. The data storage may be manual or automated. Traditional file structures are rapidly being replaced by database management systems.

Data may be classified as; Input, Output, Processed and Stored

For Example;

Input - source data may be collected from forms such as Student enrolment input forms

Important terms associated with data you should be familiar with;
Character, Field, Record, File, Database

Data v's Information

Information is

Useful processed data

Data that has meaning
Knowledge derived from data
Data placed in context

Information is;

Pertinent
Timely
Accurate
Reduces uncertainty

Input

Source data may be collected from forms

For Example;

Student enrollment input forms
Electronic sensors for reading Temperature

Output

[VDU cartoon]

Data that is displayed on a device such as a printer or Visual Display Unit (VDU), is most often presented as information (i.e. processed data),

For Example;

Client Phone list

Processed

Data that is changed by the computer,

For Example;

Weekly calculation of hours worked (hours worked times hourly rate)
Client statement

INFORMATION is Useful processed data

Stored

[hard disk]

Data that is saved electronically such as on a magnetic disk or tape.

Terms

[db terms]

Important terms associated with data you should be familiar with;

Character a letter, digit or special symbol (For example. S,2,%)
Field logically related characters (For example your last name or a phone number)
Record collection of related fields (For example, Data about you - Name, Address, Phone)
File collection of records (For example, client data, student data)
Database collects all data into one structure.

How many bytes on an A4 page?

How many bytes on an A4 page?

[A4 dimensions]

Assume;

Non-proportional font, of about 10 pitch;

Paper width = 80 characters

Paper height = 66 lines

Margins of;

top = 10 lines,

bottom = 6 lines

sides = 10 characters

Calculation

60 characters x 50 lines
= 3,000 characters
= (approx. 3 Kilobytes)

Note that 1 computer Megabyte is actually 1,024 bytes !. This is explained further in the Data - Number Systems module.

Bytes in a phone book

For Napier/Hastings (population: approx. 100,000)

	Characters per line	40
	Lines per page	x 100
	Number of columns	x 5
	Number of pages	x 190
	Total characters	======== 3,800,000 = 3.8 MB

Bytes in a book

Owen's Megabyte calculation?

Find 5 lines of your own writing

Count the number of characters (Include blanks and punctuation)

Calculate the number of characters per line.
Divide the answer in (b) by 5 (lines).

Calculate the number of characters per page.
Multiply the answer in (c) by 35 (lines)

Calculate the number of characters per book
Multiply the answer in (d) by 72 (pages)

Compute the number of Megabytes in a book
Divide the answer in (e) by 1,000,000 (1 Mbyte).

Source: Owen Giles (EIT Hawke's Bay Tutor)

Data - Overview

For Example;

Data v's Information

Information is

Information is;

Input

For Example;

Output

For Example;

Processed

For Example;

Stored

Terms

How many bytes on an A4 page?

How many bytes on an A4 page?

Bytes in a phone book

Bytes in a book

Owen's Megabyte calculation?