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Computer Systems 1 Fundamentals of Computing


How many fractional calculations can processor carry out? Processors often have a FPU (Floating Point ... Stress / Computer rage' Software manufacturers fault? ... – PowerPoint PPT presentation

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Title: Computer Systems 1 Fundamentals of Computing

Computer Systems 1 Fundamentals of Computing
  • Performance, Data Health Safety

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

Performance Terms
  • 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

Performance Terms
  • Benchmark
  • The measuring stick against which something is
  • 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
  • Risks attached
  • Overheating of CPU
  • Processing errors

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

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

CPU Performance
  • Pipelining
  • Example
  • Four instructions to carry out
  • 1, 2, 3 4
  • Pipeline Segments
  • Fetch (F), Decode (D), Execute (E)

Clock Cycle
F(2) D(1)
F(3) D(2) E(1)
F(4) D(3) E(2)
D(4) E(3)
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)

CPU Performance
  • Hyper-Threading
  • Based on the Simultaneous Multi-Threading (SMT)
  • 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

Problem Prevention / Solving
  • UPS
  • Un-interruptible Power Supply
  • Battery backup System
  • Can also perform power conditioning and surge
  • 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

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

  • 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

Basic Data Representation
  • American Standard Code for Information
  • 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//

Basic Data Representation
  • Unicode
  • Another standard for representing language
  • 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

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

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
  • 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

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
  • Introducing technology into everyday ordinary
  • Allowing everything to be networked and live

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

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

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

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 (

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

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

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
  • Ensure staff receive a Display Screen Equipment
    risk assessment and arising problems are resolved

Specific IT Regulations
  • Health and Safety (Display Screen Equipment)
    Regulations 1992
  • Measures continued
  • Give staff regular breaks away from display
  • Pay for employees' eye tests on request
  • Provide training so staff can use their VDU and
    workstation safely
  • VDU User Guide
  • http//

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

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

Solutions - Overview
  • Working environment
  • OHSA (US)
  • Occupational
  • Health and
  • Safety
  • Administration
  • UK Health and
  • Safety Executive

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

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
  • 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
  • keep the screen surface clean
  • how to adjust software settings to make text
    large enough to read easily
  • take frequent breaks

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
  • 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
  • take frequent breaks

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
  • 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

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
  • preferably detachable or height-adjustable
  • come with a lightweight carrying case with handle
    and shoulder straps

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
  • 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

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
  • 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

The Workstation
  • Desks
  • big enough to allow the user to arrange the
    screen, keyboard, documents, etc in a flexible
  • 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
  • Chair
  • be stable and allow the user to work comfortably
  • be adjustable in height
  • have a seat back adjustable in height and tilt

Social Implications of Computers
  • Computers are everywhere!
  • IT training becoming a necessity
  • Everyone prone to health and safety issues with
  • 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?

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