Computer Systems 1 Fundamentals of Computing

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Computer Systems 1Fundamentals of Computing

• Performance, Data Health Safety

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Performance, Data Jargon

• Performance Terms
• Operational
• CPU Specific
• Data Representation
• Analogue Vs Digital
• ASCII
• Unicode
• Data Reduction
• Jargon
• Deciphering some computing terminology

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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

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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 its approved
  and tested speed
• Used to force a little more power out of the
  processor
• Risks attached
• Overheating of CPU
• Processing errors

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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

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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

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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)
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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)

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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

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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

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Analogue

• A continuously varying signal
• Varying in terms of frequency, amplitude, or both
• A signal that is constantly changing
• Analogue can represent many values

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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

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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/

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Basic Data Representation

• Unicode
• Another standard for representing language
  characters
• Uses 16 bits for each character
• gt 65,000 unique characters
• Useful for complex languages (Greek, Japanese,
  etc.) special characters, symbols, etc.
• May ultimately replace ASCII
• www.unicode.org

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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

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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

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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

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What you know now

• Performance
• Hyper-threading
• Pipelining
• Problem solving
• Data Representation
• Analogue Vs Digital
• ASCII
• Unicode
• Compression
• Jargon
• AI
• HCI
• other jargon...

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Health Safety
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Health Safety

• Working with computers
• Effects on life
• Health Safety
• Social aspects
• Legal requirements / implications
• Equipment specific aspects
• Environmental issues
• Ergonomics

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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
• PDAs
• Mobile phones

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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)

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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
• Look for the hazards
• Decide who might be harmed and how
• Evaluate risks and decide whether existing
  precautions are adequate or whether more needs to
  be done
• Record your findings
• Review your risk assessment from time to time and
  revise it

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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.

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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

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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

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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

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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

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Solutions - Overview

• Working environment
• OHSA (US)
• Occupational
• Health and
• Safety
• Administration
• www.osha.gov
• UK Health and
• Safety Executive
• www.hse.gov.uk

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Solutions - Overview

• Ergonomics
• Correct posture
• Positioning of components
• Copy holders
• Better work environment
• Adjustable chair, desk, etc.
• Wrist supports
• Monitor filters
• Regular breaks

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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

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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

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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

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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

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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

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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

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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

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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 cant the computer do it?
• Laziness?
• Un-sociable society?

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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