Computer Systems


Computer Systems
Mind Map by lisawinkler10, updated more than 1 year ago
Created by lisawinkler10 almost 9 years ago

Resource summary

Computer Systems
  1. Importance
    1. Improved quality in manufacturing - robotic machinery is more accurate than humans
      1. Cheaper manufacturing - automation reduces wage costs and allows 24/7 working
        1. Faster access to information - many jobs can be done more quickly
          1. Better decision making - with lots of facts organised and available, decisions can be better informed
            1. New ways of doing business - more buying online, more choice, cheaper goods; facilities such as the internet and ATMs would not be possible without computer systems
              1. New ways of communicating - email, SMS, cell phones - are being developed all the time
              2. Examples
                1. Satnav
                  1. Inputs: signals from satellites, inputs from user
                    1. Outputs: route, places of interest, warnings
                      1. Processing: check position, locate on map, output map
                      2. Car engine management
                        1. Inputs: temperature, CO2 levels, speed
                          1. Outputs: signals to carburettor, data to engine diagnostics
                            1. Processing: check values against set parameters, produce fault codes
                            2. Holiday booking
                              1. Inputs: dates, destination, credit card details
                                1. Outputs: itineraries, air tickets, hotel reservations
                                  1. Processing: check availability, produce documents
                                2. Types
                                  1. General-purpose systems, such as laptops and smartphones, are designed to perform multiple tasks (various applications can be loaded)
                                    1. Dedicated systems are specially produced to perform a single function, for example a ticket-vending machine
                                      1. Control systems control machinery rather than produce outputs for humans to respond to. Important in manufacturing processes but also in domestic gadgets.
                                        1. Industrial robots are an important application of control systems.
                                        2. Embedded system are part of a larger system. They include portable devices: digital watches, satnavs, cameras, and larger installations: traffic lights, controllers of machinery in factories
                                          1. Can be simple or highly complex (most cars have up to 50 systems looking after fuel flow, window control, etc.)
                                          2. Expert systems are designed to behave like a human expert.
                                            1. They have three component parts: a knowledge base (a database of facts), an inference engine (software that makes deductions using the knowledge base) and an interface (to allow human access)
                                              1. Commonly used for: diagnosing diseases, finding faults in machinery, choosing complex products (mortgages, insurance policies), making credit checks and suggesting purchases to coconsumers
                                              2. Management information systems bring together the information from all parts of an organisation so that managers can make sensible decisions
                                                1. They cover: technology, data, and people, and typically produce regular reports based on the organisation's data
                                                  1. Examples: Decision Support Systems are used by middle management to support day-to-day decision making, Executive Information Systems produce reports using data from throughout an organisation and support decisions about the organisation's strategy, Office Automation Systems automate workflow and maximise the efficiency of data movement, School Management Information Systems deal with school administration, teaching and learning
                                                2. Reliability
                                                  1. Mistakes in design can lead to: down time, expensive errors, data loss, and compromised privacy
                                                    1. Computers are central to many life-or-death situations; aircraft navigation, railway signalling, diagnosis of diseases, robotic surgery, DNA sequencing
                                                      1. Also refers to data integrity - data being accurate and consistent (stored data reflects real-world reality)
                                                        1. Data integrity can be compromised by: human errors, software bugs, viruses and other malware, hardware malfunctions, natural disasters
                                                          1. Ways to reduce risks to data: backing up data regularly, controlling access to data via security mechanisms, using validation rules to prevent the input of invalid data, using error detection and correction software when transmitting data
                                                          2. Reliability is improved by thorough testing but it can never be complete because software is so complex and testing is expensive and time consuming
                                                          3. Standards
                                                            1. Important because they enable equipment from different manufacturers to work together, make learning systems easier, minimise waste, help ensure fair play and access to markets, bring costs down by opening markets to competition
                                                              1. They exist for programming languages, operating systems, data formats, communication protocols and electrical interfaces
                                                                1. Types of Standards
                                                                  1. De facto standards (develop over time and ensure that systems can be used by everyone); PostScript, QWERTY keyboard, Microsoft Word
                                                                    1. De jure standards (by law; so universally accepted that they have to be adhered or communication is impossible); ASCII, PDF, Unicode, TCP/IP
                                                                      1. Proprietary standards (owned by organisation to ensure compatibility between products and reduce competition (e.g. Apple locks users into using their software and Windows has the same 'look and feel' to make learning them easier
                                                                        1. Industry standards are set by non-commercial organisations (ANSI - programming languages, ITU - communication protocols, ISO)
                                                                          1. Open standards are produced collaboratively and are publicly available, not for profit and sufficiently detailed to allow interoperability. They ensure that access isn't dependant on a single application or particular hardware platform. (World wide web, HTTP, HTML)
                                                                        2. Ethical and Legal Issues
                                                                          1. Data protection
                                                                            1. Typical laws state that organisations must protect data from unauthorised access, allow people to view data held about them, and correct information when requested
                                                                              1. Is needed because it's easy to copy, transmit and match data and make judgements about people
                                                                              2. To do with privacy, data security, copyright, and terrorism
                                                                              3. Environmental issues
                                                                                1. Waste of obsolote computers can mean toxic chemicals (lead, cadmium) can leach out into the soil in landfills, especially when E-waste is shipped to developing countries. Also release dangerous chemicals (dioxins) when burnt.
                                                                                  1. Use a lot of energy which can be reduced by using solid state storage rather than rotating disk drives, modern screens which are less energy insensitive, and automatic standby switching
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