Section 5: Information Processing

Question 1

Data

Answer 1

This is raw unprocessed facts e.g. 32, 28, 36. This data can represent anything and therefore has no meaning.

Question 2

Information

Answer 2

This is processed data e.g. Jane scored 32, Phillip scored 28 and Barry scored 36. This information tells us how well or poorly the student performed. Information has meaning.

Question 3

Information Processing

Answer 3

Information processing is using computers to process data into information. Information Processing takes place when a machine or processor interacts with the outside world and acts on the inputs its receives. The basic sequence of events in processing information includes (1) input, (2) processing, (3) storage and (4) output.

Question 4

Commercial data processing

Answer 4

This refers to the use of computers in businesses to automate or perform administrative tasks.

Question 5

Control systems

Answer 5

This is the use of computers to control machinery automatically.

Question 6

Scientific data processing

Answer 6

This is the use of computers to collect data during experiments. Sensors are used to capture data over a period of time. The data collected is used to make connections between the data. Statistical methods are used to analyze the figures collected and the results are display as charts.

Question 7

Information Management

Answer 7

Information Management is the task that ensures that all data is input accurately, stored correctly, retrieved easily and output in a way that provides useful information.

Question 8

Source documents

Answer 8

A source document is one that contains data that is going to be input into a computer system. Once the data has been entered it should be filed away safely because the data may have to be checked again.

Question 9

Human-readable documents

Answer 9

A human-readable document is any document that needs to be read by humans e.g. forms that are filled in by hand and has to be read before the data is entered on a keyboard.

Question 10

Machine-readable documents

Answer 10

A machine-readable document is one on which the data can be ‘read’ by an input device, such as a scanner or mark reader, directly into the computer system. Examples of machine-readable documents are multiple choice answer sheets and barcodes on labels of products.

Question 11

Turnaround documents

Answer 11

A turnaround document is one that is printed by a computer system but is later used to input new data into the same system. E.g. a tax return form with the employee’s personal information pre-printed on it.

Question 12

Data verification

Answer 12

Data verification is a process whereby a person checks that data has been correctly entered into a computer system. e.g. double entry verification

Question 13

Data validation

Answer 13

Data validation is any check carried out by a computer system when data is entered, to identify data that cannot be correct. e.g. Range checks, Data type checks, Inconsistency checks (consistency checks)

Question 14

Double entry verification

Answer 14

In this method, a second person enters the same data and the computer system checks each data item entered the second time against the first data entry.

Question 15

Range checks

Answer 15

These check whether numerical data is within expected limits e.g., if you are asked to enter someone’s age, the number should be between 0 and 110 years; or if you are asked when you joined an organization, the date cannot be a date in the future.

Question 16

Data type checks

Answer 16

These check whether the data is of the correct type, such as number, date or text. E.g. age is numerical, so a data check would notice if a letter was entered.

Question 17

Inconsistency checks (consistency checks)

Answer 17

These check one piece of data against another. E.g. if data includes both gender (M or F) and title (Mr., Mrs. or Miss). If someone has entered M and Miss, then the two data items are inconsistent.

Question 18

Serial files

Answer 18

In a serial file, the records do not follow each other in any particular order. If another record needs to be added, it can be added to the end of the file.

Question 19

Sequential files

Answer 19

Sequential files are like serial files except that the records are held in a sequence e.g. if you decide to order pupil files in ascending or descending order of student number. One of the fields is used for the ordering. This field is called the sort key e.g. it is very common to sort a file of personal details using “surname” as the sort key. This is also known as sequential field ordering.

Question 20

Random files

Answer 20

Random files are stored in any order on the disk surface. The OS keeps a map of the disk surface and the read/write heads use this map to find the data.

Question 21

Serial access

Answer 21

This means the records are accessed in the same order as they were stored. To read a serial file, a computer has to read each record until it reaches the one required.

Question 22

Sequential access

Answer 22

This means reading or writing data consecutively. With sequential access the records are in order. Therefore if just one record is required, the method is slow but if all the records are required, it is very fast.

Question 23

Direct access or random access

Answer 23

With a direct or random access files it is possible to go directly to a record without having to look at any other records. You can access random access files directly.