Systems and the Information-Processing Cycle
What turns a pile of parts into a system, and where does data change form inside a computer?
- Define the concept of a system.
- Identify the five components of a computer system: hardware, software, data, peopleware and procedures.
- Explain the five stages of the information-processing cycle (IPOS+C).
- Classify everyday actions as input, processing, storage, output or communication.
Overview
A system is a set of parts that work together for a shared purpose. Your body is a system; so is a PMV route; so is a computer. A computer system is more than the box on the desk — it is hardware, the software that instructs it, the data it works on, the people who use it and the procedures they follow. When any one part is missing the system stops delivering its purpose. This chapter also introduces the information-processing cycle, the pattern every computer follows: Input, Processing, Storage, Output and Communication (IPOS+C).
What is a system?
A system has parts (components), links between the parts, and a purpose. Remove the purpose and you only have a collection. In the circulatory system the heart, blood and vessels each have a job, and together they move oxygen. A computer system works the same way: each part has a job, and together they turn raw data into useful information.
The five components of a computer system
Every working computer installation contains all five of these.
Learn these in order — exam questions often ask for all five:
- Hardware: The physical parts you can touch: system unit, keyboard, monitor, printer, cables.
- Software: The instructions: the operating system, applications and utilities.
- Data: The raw facts entered into the system — marks, names, sensor readings, photographs.
- Peopleware: The users, operators, technicians and programmers who run and maintain the system.
- Procedures: The written rules for using the system: backup routines, log-in policy, shutdown steps.
The information-processing cycle (IPOS+C)
Data enters the system, is worked on, is kept for later, is presented to a person, and is often sent somewhere else. Trace those five stages in any device and you understand what it is doing.
The five stages, with a PNG example for each:
- Input: Raw data enters: you type a student's mark, or a card is swiped at an EFTPOS terminal.
- Processing: The CPU works on the data: the total and average of the marks are calculated.
- Storage: The result is kept for later: saved to the hard disk or written into the class record file.
- Output: The result is presented: printed on a report card or shown on screen.
- Communication: The result is transmitted: emailed to the parent, or uploaded to the provincial education office.
Data changes form at each stage — from keystrokes to numbers in RAM, to magnetic patterns on a disk, to light on a screen.
Information vs data
Data is raw and meaningless on its own: 78, 65, 90. Information is processed data with meaning: 'the class average in ICT is 77.7%'. The whole point of the processing stage is to turn one into the other.
Activity — The processing relay
- Form groups of five. Each member takes one stage: input, processing, storage, output, communication.
- The 'input' member receives a maths problem on a slip of paper and passes it on.
- 'Processing' solves it, 'storage' writes the answer in the group log book, 'output' announces it, 'communication' delivers it in writing to another group.
- After the relay, write down what form the data was in at each stage.
- Individually: draw and label the IPOS+C cycle for withdrawing money from an ATM.
- List the five components of a computer system.
Reveal answer
Hardware, software, data, peopleware, procedures.
- Give the five stages of the information-processing cycle.
Reveal answer
Input, processing, storage, output, communication.
- What is the difference between data and information?
Reveal answer
Data is raw facts; information is processed data that has meaning.
- In an EFTPOS payment, what is the input?
Reveal answer
The card details and the PIN entered by the customer.
Choose a system in your school (the canteen, the library, the roll-marking system) and describe its five computer-system components — even if part of it is still on paper.