ocr computing gcse © hodder education 2013 slide 1 ocr gcse computing chapter 1: introduction

OCR Computing GCSE © Hodder Education 2013 Slide 1

OCR GCSE Computing

Chapter 1: Introduction


Index to topics

SystemsEmbedded systemsReliabilityStandardsRegulationEnvironment


Chapter 1: Systems

What is a system?• A system is a collection of parts that work together

for a common purpose. • For a system to be useful, it must produce

something – an output.• It needs to receive and process inputs in order to

produce outputs.


Chapter 1: Systems

Examples of systemsHoliday booking system:

Computer game:


Chapter 1: Systems

• Computer systems are based on processing data and producing information.

• They are fast, and the important thing about them is that they are programmable.

• Computer systems are found in most electronic gadgets. – For example, washing machines, cameras, burglar alarms

and telephones


Chapter 1: Systems

• Computer systems used in electronic gadgets have all of the basic functionality that drives a desktop PC. – There are input and output devices, storage, a processor

and, most importantly, software.


Chapter 1: Systems


Chapter 1: Embedded Systems

• Software that is programmed to carry out a number of dedicated functions. For example, the software to run a washing machine is stored on a computer chip and embedded into the system.



• Control systems can be quite complex, for example an engine management system.



• A typical engine management system in a car has over 50 processors, which explains why car engine faults can be difficult to trace without the right equipment.

• The embedded systems in a car look after various safety features and it is easy to see why these must be reliable and thoroughly tested, both as individual items and as integrated systems.


Chapter 1: Reliability

Use of and reliance on computer systems• Computer systems are important and are involved

in most human activities:– Safety– Travel– Business– Entertainment– Education– Science

• Given our dependence on them, it is vital we are able to trust in the reliability of these systems.



• IT failures can be catastrophic and expensive.• Air travel makes extensive use of computer

systems. If these fail, then lives are put in danger:

• On 7th October 2008 an airbus operated by Quantas started to pitch violently because of a fault in an inertial reference sensor, causing the auto-pilot to try to correct suddenly.

• Fortunately there were few major injuries on this occasion. • The problem was caused by faulty data sensors providing

incorrect information to an automatic control system.



Badly designed IT systems failing to achieve the desired result can cost millions or even billions of pounds that cannot be recovered.

http://www.information-age.com



• Thorough analysis of the situation and thorough testing of the system are essential parts of the process to avoid such dangers.– The NatWest banking system failure was, according to

one banking technology specialist, such a failure:• the glitch was almost inevitably caused by the introduction of a

change. "This would be either a software or hardware upgrade to either the bank's payment processing systems or the mainframe systems that handle the actual account data. If an upgrade is not sufficiently tested first, then this sort of problem occurs.”

– (David Silverstone NMQA, Guardian 22/06/12)


Chapter 1: Standards

• Standards agreed by the IT industry are an essential element of system design and development.

• “ICT standards are tools that help vendors—including hardware and software providers—develop products and services that work together and enhance interoperability among different technologies and processes.” (Microsoft)

• Open standards are agreed so that community developers can modify source code freely available in the public domain, and do so effectively.



• Hardware standards allow the interconnection of devices;

• Software standards allow software to share data efficiently;

• Some standards simply develop through common usage, eg HTML and PDF.



Hardware standards allow devices to connect:



• Hardware standards go beyond simply connecting peripheral devices. Standards exist for all aspects of computer hardware, including:– Visual displays and ports; – Internal connections such as SATA or PCI;– Hard drive characteristics;– Motherboard architecture;– Processor specification.



• Software standards include agreement on various file types, enabling software to use data from other systems effectively:– For example, a number of image file types exist

including png, jpeg, GIF, TIFF and various others. Knowing what to expect in such a file makes it possible for software packages to deal with them.



• Some software standards are designed, such as the Joint Photographic Experts Group image type or JPEG.

• Others develop through common usage such as HTML (hypertext markup language), and PDF, (portable document format).

• In order to communicate, share data and be compatible, most software dealing with word processed documents or spreadsheet files will understand the .doc and .xls file types.



Open standards provide various benefits:– Application independence: access to resources is not

dependent upon a single application.– Platform independence: access is not restricted to a

specific hardware platform.– Long-term access: resources are openly developed and

updated.



Developers working on open source material are encouraged to cooperate and share ideas with others, because:

– Open standards are maintained by not-for-profit organisations, which ensure open decision-making about developments;

– Access to the resources is freely available to all on a royalty free basis;

– There are no constraints on the re-use of the standard.


Chapter 1: Regulation

• IT systems store vast amounts of data about individuals.

• If this data is not correct then there may be serious consequences:– If credit information is incorrect, then there may be

problems obtaining a mortgage or bank account.– If an individual is associated incorrectly with a crime,

then obtaining employment may be impossible.



If data is lost or stolen then there may well be issues with identity theft:

– Following a security breach at an American data broker in 2005, a Connecticut salesman had his identity stolen. The thief bought cars, motorcycles, furniture and other items under the salesman’s name over four months, spending $265,000.

– The victim has spent over 2,000 hours trying to reclaim his life after having his identity stolen.

– There are around 10 million cases of identity theft in the USA every year.



• Data is valuable and must be protected, and the Data Protection Act attempts to regulate organisations that store data.

• Data should:– be processed fairly and lawfully;– be obtained for a specified and lawful purpose and used

accordingly;– be limited to the specified data, be accurate, and up to date;– be kept only for as long as necessary for the specified purpose;– be kept securely;– not be transferred outside the EU.


Chapter 1: RegulationA news article from techweekeurope.co.uk, August 2012, contains the following:

– The Metropolitan Police Service has arrested a former Times journalist in an investigation into computer hacking offences.

– The Met said a 28-year-old man had been arrested at his home address in North London this morning as part of Operation Tuleta, the investigation into criminal breaches of privacy including computer hacking, running alongside the phone-hacking scandal investigation.

– He was arrested for suspected offences under the Computer Misuse Act 1990, and suspected conspiracy to pervert the course of justice.



The Computer Misuse Act became law in 1990 and covers four major offences:

– Unauthorised access to computer material;– Unauthorised access with intent to commit or facilitate

a crime;– Unauthorised modification of computer material;– Making, supplying or obtaining anything which can be

used in computer misuse offences.



The Computer Misuse Act covers:– illegal access and the associated privacy issues;– phishing for personal details;– keylogging software to obtain information about what a

user is entering on their keyboard;– introducing viruses and other malware into a computer

system.



Intellectual Property• Developers spend a lot of time and money creating

applications. If people share this software then the developer will not recoup the costs of development and will not be able to continue developing software.

• Estimates suggest almost half of all software is copied, costing thousands of jobs and billions of pounds in revenue.

• The Copyright, Designs and Patents Act protects intellectual property by making it illegal to copy software or music, images or photographs from the web, or to copy text from web pages to use as your own work.



• Organisations working with computer professionals seek to maintain standards of conduct by introducing voluntary codes of practice.

• Typically, these will provide guidance on acceptable behaviour, including:– Acceptable use policies;– Netiquette;– Rights and responsibilities;– Good practice.


Chapter 1: EnvironmentComputer hardware disposalComputer hardware components contain various toxic substances that must be disposed of carefully.


Chapter 1: Environment

Computer Hardware RecyclingComputers also contain some valuable substances that should be recycled, including:

– Copper in circuit boards and wiring;– Gold on circuit boards and in connectors;– Metals like zinc, cadmium, mercury – these can be

recycled to reduce the demand for extracting them from new sources on the planet;

– Plastic – this can be recycled, reducing the demand for petroleum from which it is made.

ocr computing gcse © hodder education 2013 slide 1 ocr gcse computing chapter 1: introduction

Documents