1. Computer Systems 1 Fundamentals of Computing Performance, Data + Health & Safety

2. Computer Systems 1 (2004 - 2005) Performance, Data & Jargon Performance Terms  Operational  CPU Specific Data Representation  Analogue Vs Digital  ASCII  Unicode  Data Reduction Jargon  Deciphering some computing terminology

3. Computer Systems 1 (2004 - 2005) Performance Terms FLOPS  FLoating Point Operations Per Second How many fractional calculations can processor carry out? Processors often have a FPU (Floating Point Unit) designed to do these calculations  Improve number intensive tasks  Such as graphics rendering  Also called maths-coprocessor  Another way to measure processor speed MFLOPS = MegaFLOPS (MillionFLOPS /s) GFLOPS = GigaFLOPS (BillionFLOPS /s)  Thought to be inaccurate Some operations can take longer than others

4. Computer Systems 1 (2004 - 2005) Performance Terms ‘Benchmark’  The measuring stick against which something is measured  Tests which have been devised to measure a specific type of equipment or program  Used to measure and compare performance of computer software of hardware ‘Overclock(ing)’  Processes happen in sync with clock cycle Theory: Quicker Clock = Quicker Computer  Forcing a CPU to run faster than it’s approved and tested speed  Used to force a little more power out of the processor  Risks attached Overheating of CPU Processing errors

5. Computer Systems 1 (2004 - 2005) CPU Types / Performance CISC  Complex Instruction Set Computer Supports up to 200 instructions Instructions for complex operations Original Pentium processors & x86 RISC  Reduced Instruction Set Computer Less instructions than CISC Less Instructions = Faster (?) Cheaper to produce Puts bigger burden on software (?) Motorola processors found in Apple computers Pentium 2, 3 & 4 Use CRISC  Combination of CISC & RISC

6. Computer Systems 1 (2004 - 2005) CPU Performance ‘Pipelining’  Technique used in modern processors CPU fetches next instruction while processing current instruction  A bit like a factory assembly line Pipeline split into segments  Each segment executes a specific function in sync with other segments then data is moved along  Sync is produce by clock cycle Pipeline Segments  Fetch  Decode  Execute  Can reduce bottleneck restrictions

7. Computer Systems 1 (2004 - 2005) CPU Performance ‘Pipelining’  Example: Four instructions to carry out  1, 2, 3 & 4 Pipeline Segments  Fetch (F), Decode (D), Execute (E) Clock Cycle F(1)F(2) D(1) F(3) D(2) E(1) F(4) D(3) E(2) D(4) E(3)E(4)

8. Computer Systems 1 (2004 - 2005) CPU Performance ‘Hyper-Threading’  Hyper-Threading Technology (HT Technology) is a groundbreaking technology that enables a processor to execute two threads in parallel — allowing you and your software to multi-task more effectively than ever before. (Intel)

9. Computer Systems 1 (2004 - 2005) CPU Performance ‘Hyper-Threading’  Based on the Simultaneous Multi-Threading (SMT) method Parallel execution of process threads  Allows programs to run multiple threads in parallel on one processor A Thread can be thought of as a single task that makes up a process  Involves creating two logical processors System becomes a pretend dual-processor machine  A logical processor can be multi-tasking  Provides multi-tasking through time-slicing  Is a theoretical parallel processing system  Fools the OS into thinking there are two processors

10. Computer Systems 1 (2004 - 2005) Problem Prevention / Solving UPS  Un-interruptible Power Supply  Battery backup System  Can also perform power conditioning and surge protection ‘Cleans’ power supply POST  Power On Self Test Checks performed by the BIOS when computer is powered up Beep codes Also have POST diagnostic cards

11. Computer Systems 1 (2004 - 2005) Analogue A continuously varying signal  Varying in terms of frequency, amplitude, or both A signal that is constantly changing Analogue can represent many values

12. Computer Systems 1 (2004 - 2005) Digital A signal with discrete value changes Signal levels are either on or off Often thought of as either 1 or 0, especially in computers, but digital can represent many different values using discrete levels

13. Computer Systems 1 (2004 - 2005) Basic Data Representation ASCII  American Standard Code for Information Interchange  Represents English language characters using numbers (0 to 127) 7 bits for each character  E.g- 115 is a small ‘s’  Extended ASCII (uses 8 bits = more characters)  http://www.asciitable.com/

14. Computer Systems 1 (2004 - 2005) Basic Data Representation Unicode  Another standard for representing language characters  Uses 16 bits for each character > 65,000 unique characters  Useful for complex languages (Greek, Japanese, etc.) special characters, symbols, etc.  May ultimately replace ASCII  www.unicode.org

15. Computer Systems 1 (2004 - 2005) Data Reduction ‘Compression’  Using an algorithm to reduce the size of a computer file or program  Loss-less compression Information is compacted without destroying or removing any data from the file E.g- zipping a file  Lossy compression Information is compacted but information deemed to be insignificant or redundant is thrown away E.g- MP3

16. Computer Systems 1 (2004 - 2005) Jargon Busting AI  Artificial Intelligence  Attempting to make the computer behave like a human or think for itself  Used in games to simulate human and random behaviour  Expert systems or knowledge bases allow decisions or recommendations to be given based on input Meta  Information about information  Thing of Meta as meaning “about”  Meta-data = data about data  Meta-language = a language about a language

17. Computer Systems 1 (2004 - 2005) Jargon Busting HCI  Human Computer Interaction  How the user and computer communicate and interact with each other  Make interaction faster, easier and better  Many different forms of interaction: Haptic: movement, gestures, physical interaction Auditory: using sounds to interact Pervasive Computing  “Ubiquitous Computing”  Integration of computing technology to everyday life  Introducing technology into everyday ‘ordinary’ objects  Allowing everything to be networked and live

18. Computer Systems 1 (2004 - 2005) What you know now:  Performance Hyper-threading Pipelining Problem solving  Data Representation Analogue Vs Digital ASCII Unicode Compression  Jargon AI HCI other jargon...

19. Computer Systems 1 (2004 - 2005) Health & Safety

20. Computer Systems 1 (2004 - 2005) Health & Safety Working with computers Effects on life  Health & Safety  Social aspects  Legal requirements / implications  Equipment specific aspects  Environmental issues  Ergonomics

21. Computer Systems 1 (2004 - 2005) Working with computers Risks and effects associated with computer use These are not only health related but also have social and economical implications Computers and technology encroach on many aspects of everyday life  Desktop computers  Laptop computers  PDA’s  Mobile phones

22. Computer Systems 1 (2004 - 2005) Working with computers “All businesses must ensure their workplace - whether this is a factory, office or shop - meets minimum health and safety standards.” IT Related employer responsibilities:  carrying out a risk assessment  ensuring employees use IT equipment safely  reporting accidents or dangerous incidents in the workplace to the relevant authorities UK Law ( www.businesslink.gov.uk )

23. Computer Systems 1 (2004 - 2005) General Health & Safety Risk Assessment  All business must carry out an assessment  Issues What are the potential hazards? What hazard prevention measures are in place? Five Step Risk Assessment 1. Look for the hazards 2. Decide who might be harmed and how 3. Evaluate risks and decide whether existing precautions are adequate or whether more needs to be done 4. Record your findings 5. Review your risk assessment from time to time and revise it

24. Computer Systems 1 (2004 - 2005) General Health & Safety Equipment Regulations  Equipment must be suitable and safe to use under the Provision and Use of Work Equipment Regulations 1998 (PUWER). All equipment must be:  suitable for its intended use  maintained in a safe condition  accompanied by suitable safety measures such as protective devices, markings and warnings  Only people who have received adequate information, instruction and training use the equipment.

25. Computer Systems 1 (2004 - 2005) Specific IT Regulations Health and Safety (Display Screen Equipment) Regulations 1992 Measures:  Ensure workstations and workplace layout meet a range of minimum requirements in areas such as clarity of image, adjustable chairs and suitable lighting  Ensure staff receive a Display Screen Equipment risk assessment and arising problems are resolved

26. Computer Systems 1 (2004 - 2005) Specific IT Regulations Health and Safety (Display Screen Equipment) Regulations 1992 Measures continued:  Give staff regular breaks away from display screens  Pay for employees' eye tests on request  Provide training so staff can use their VDU and workstation safely VDU User Guide  http://www.hse.gov.uk/pubns/indg36.pdf

27. Computer Systems 1 (2004 - 2005) Health and Safety Predominantly because of keyboard and mouse use  RSI (Repetitive Strain Injury) Primarily affects the hand and arms (pain!!!) Can cause permanent damage  CTS (Carpal Tunnel Syndrome) Mainly affects the wrists of computer users  Especially in the mouse hand Swelling of tendons, causes pressure on the nerves

28. Computer Systems 1 (2004 - 2005) Health and Safety VDU use  VDU = Visual Display Unit The monitor or screen to you and I  Eye strain  Poor positioning of monitor  Issues with electrostatic fields Skin and eye irritation  Magnetic & light radiation  Issues with electromagnetic fields Reduction of immune system effectiveness

29. Computer Systems 1 (2004 - 2005) Solutions - Overview Working environment OHSA (US)  Occupational Health and Safety Administration www.osha.gov UK Health and Safety Executive www.hse.gov.uk

30. Computer Systems 1 (2004 - 2005) Solutions - Overview Ergonomics  Correct posture  Positioning of components  Copy holders  Better work environment  Adjustable chair, desk, etc. Wrist supports Monitor filters Regular breaks

31. Computer Systems 1 (2004 - 2005) VDU Legal Requirements Computer screens should:  tilt and swivel to suit the needs of the user  be adjusted to the correct height for the user  show clear characters with adequate spacing  show a stable image with no flickering  have easily adjustable brightness and contrast controls  be free of reflected glare  have a screen size suitable for its intended use You should also ensure that users know:  how to adjust brightness and contrast controls to suit  keep the screen surface clean  how to adjust software settings to make text large enough to read easily  take frequent breaks

32. Computer Systems 1 (2004 - 2005) Keyboard Legal Requirements Keyboards should:  be tilt adjustable and separate from the screen to allow the user to work comfortably  have enough space in front of them to allow the user to rest their hands and arms when not keying  be legible and have a matt surface to minimise glare You should also ensure that users:  adjust the keyboard to get a comfortable position  keep their wrists straight when keying  use the keys lightly and not overstretch their fingers  take frequent breaks

33. Computer Systems 1 (2004 - 2005) Pointing Device Legal Requirements If an employee uses a mouse, trackball or other pointing device for long periods, they may develop problems in their hands, wrists or upper body Minimise risk by:  Train user to use the mouse with relaxed arm and a straight wrist  informing the user that their fingers should rest lightly on the buttons and not press too hard  limiting the length of intensive mouse sessions  ensuring users take frequent short breaks  ensuring the device is suitable for the task  training the user in keyboard shortcuts  training the user to adjust the software settings - these control the reaction time between the mouse and the cursor on the screen

34. Computer Systems 1 (2004 - 2005) Laptop Advice Some design features on laptops and portable computers can make them uncomfortable to use for long periods  Employees shouldn't therefore use laptops where full-sized equipment is available Laptops should:  be as light as possible - 3kg or under  be fitted with as large and clear a screen as possible preferably detachable or height-adjustable  come with a lightweight carrying case with handle and shoulder straps

35. Computer Systems 1 (2004 - 2005) Laptop Advice Laptops should:  have a tilt-adjustable keyboard  be able to be used with a docking station  have friction pads underneath to prevent sliding across work surfaces  have enough memory and speed for the software used  be fitted with as long a battery life as possible and have extra transformer/cable sets provided so that the user has a set in each main location where the equipment is used

36. Computer Systems 1 (2004 - 2005) Laptop Advice Laptops users should be aware of:  comfortable postures for using a laptop  using the keyboard at the right height  adjusting the screen to reduce reflection and glare  the need for regular rest breaks  how to report any problems that develop  how to reduce the manual handling risk, eg by reducing the amount of extra equipment and paperwork to be carried  how to reduce the risk from theft or mugging

37. Computer Systems 1 (2004 - 2005) The Workstation Desks:  big enough to allow the user to arrange the screen, keyboard, documents, etc in a flexible way  have a matt surface  big enough to let the user work comfortably & change position  be stable and positioned so that it's comfortable and easy to use where an employee uses a document holder Chair:  be stable and allow the user to work comfortably  be adjustable in height  have a seat back adjustable in height and tilt

38. Computer Systems 1 (2004 - 2005) Social Implications of Computers Computers are everywhere!  IT training becoming a necessity  Everyone prone to health and safety issues with technology  Stress / ‘Computer rage’ Software manufacturers fault?  Information easily available and easy to share  Less need for social interaction  Why can’t the computer do it?  Laziness?  Un-sociable society?

39. Computer Systems 1 (2004 - 2005) Health & Safety What you know now:  Aspects of safety  General working requirements  IT Specifics Monitors Working with computers Health & Safety Issues VDU usage Workstation Equipment safety