Chapter 1: Computer Systems Flashcards
Computer system
All the parts that make a computer work, including the hardware, software and data. This may not be a traditional computer.
e.g. holiday booking, car engine management, washing machine, satnav, ATM at cash points, travel card (e.g. Oyster card)
What does the computer do with input?
Input –> Process –> Output ( + Storage)
Computer systems are based on processing data, and producing information.
Computer
An electronic, programmable data processing machine.
System
A collection of parts that work together for some defined purpose.
How have computers improved our lives?
- Better quality manufacturing (more accurate, and consistent)
- Cheaper manufacturing (no wage, and constantly working)
- Faster access to information (jobs can be done quicker)
- Better decision making (more informed as facts organised, and available)
- New ways of doing business (online, more choice, cheaper)
- New ways of communicating (email, SMS, mobile phones)
General purpose system (type of computer system)
Personal computers (desktops, laptops, notebooks, tablets, smart phones) are designed to perform multiple tasks. Various applications (apps) can be loaded for more purposes.
Dedicated system (type of computer system)
Specially produced to perform a single functions, or set of functions e.g. ticket vending machines at a train station can not be used for any other purpose.
Control system (type of computer system)
Computer systems that control machinery (e.g. industrial robots, robots used for accurate surgery), rather that produce output for humans to read, or respond to. They are important in manufacturing processes, but are increasingly part of household gadgets.
Embedded system
A computer system with a dedicated function within a larger mechanical, or electrical system e.g. engine management system
Embedded systems are often control systems.
Examples: digital watches, satnav, cameras, MP3 players, traffic lights, machinery controllers in factories.
Embedded systems can be very simple, or highly complex e.g. avionics system in aircraft. Most cars now have up to 50 computer systems (e.g. fuel flow, window control, cruise control, and fault management).
How many computer systems do most cars now have?
50 computer systems.
They look after a variety of things such as fuel flow, window control, cruise control, and fault management.
Expert system
A computer system that is designed to behave like a human expert.
The knowledge that they uses must be inputted first.
They have three component parts:
1) A knowledge base ( a database of facts)
2) An inference engine (software that makes deductions using the knowledge base)
3) An interface (to allow a human user to access the system)
Common uses: diagnosing diseases, finding faults in machinery, choosing complex products (mortgages, insurance policies), suggesting purchases to consumers, making credit checks.
Management information system
A computer system that brings together the information from all parts of an organisation so that managers can make sensible decisions.
They cover technology, data, and people.
They typically produce regular reports based on the organisation’s data.
Examples: used by middle management to support day-to-day decision making, produce reports about the organisation’s strategy, automate workflow, maximise the efficiency of data movement, school administration, teaching, and learning.
Reliability
Computers are central to a lot of what we do, they must be reliable.
Life-or-death: aircraft navigation, and control; railway signalling, and medical situations.
Medical: record keeping, diagnosis of diseases, CAT scans, drug interactions; use of search engines, and expert systems to check symptoms; robotic, or remote surgery; and DNA sequencing.
Mistakes can lead to down time, expensive errors, data loss, and compromised privacy.
Data integrity
Data must always be accurate, and consistent. It must reflect the real-world reality, They normally have rules that prevent inconsistent changes being made to underlying data.
Can be compromised by: human error in entry, errors when data is transmitted between computed, software bugs; viruses, and other malware; hardware malfunctions, and natural disasters.
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; and using error detection, and correction software when transmitting data.
Reliability, and testing. Why can testing never be complete?
Reliability is improved through testing. The purpose of testing is to uncover errors.
Testing can never be complete as
- Software is so complex
- Testing is expensive
- Testing is time consuming
There are huge numbers of pathways through most sodern systems so there are usually errors in even the most extensively tested systems.
