ICE: Introduction to Computing Environments

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ICE Introduction to Computing Environments

• Set the context for the course
• Examine the range of activities and skills that
  make up Computer Science
• Appreciate the range of forms of digital
  informationtextual,graphical,audio-visual

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Computers in (US) Society

• Occupation employed 1996 projected 2006
• Computer scientists 212,000 461,000
• Computer engineers 216,000 451,000
• Systems analysts 506,000 1,025,000
• Computer programmers 568,000 697,000
• Total 1,502,000 2,634,000
• All occupations
• Source U.S. Department of Labor, Bureau of Labor
  Statistics, 1996 Industry-Occupation Employment
  Matrix

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Computer Scientists

• Academic theory, to hardware, to language
  design.
• Private designing programming tools,
  knowledge-based systems, or computer games.
• Database administrators
• Computer support specialists
• Network administrators
• System security specialists
• Telecommunications specialists

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Computer Engineers

• Design new computing devices or computer-related
  equipment
• Software engineers design and develop both
  packaged and systems software.

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Systems Analysts

• Study business, scientific, or engineering data
  processing problems and design new solutions
  using computers
• They work to help an organization realize the
  maximum benefit from its investment in equipment,
  personnel, and business processes.

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Computer Programmers

• Produce software
• Execute work pre-specified by systems analysts
• 'The transition from a mainframe to a primarily
  PC-based environment has blurred the once rigid
  distinction between the programmer and the user.'

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What Are Users?

• What is the task that a User might perform that
  a computing professional would not?
• Expectations of what a user is changes with time
• Data-inputter/Writer of word processed
  documents/Designer of leaflets/Web designer?
• Where does expertise begin

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Computing Professional

• Somewhere between the user and the machine

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Definition of Computing

• compute (km-pyt) v. computed, computing,
  computes. v. tr.
• 1. To determine by mathematics, especially by
  numerical methods computed the tax due. See
  Synonyms at calculate.
• 2. To determine by the use of a computer.
• v. intr.
• 1. To determine an amount or number.
• 2. To use a computer.
• n.
• Computation amounts beyond compute.

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Computer

• Input
• Processing
• Storage
• Output

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Microcomputer System
What does the computer process?
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Decimal Number System

• base number 10
• ten number values 0 1 2 3 4 5 6 7 8 9

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Binary Number System

• base number 2
• two number values 0 1

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Binary Number System(cont.)

• 251 11111011
• 1 x 2 x 2 x 2 x 2 x 2 x 2 x 2 128 plus
• 1 x 2 x 2 x 2 x 2 x 2 x 2 64 plus
• 1 x 2 x 2 x 2 x 2 x 2 32 plus
• 1 x 2 x 2 x 2 x 2 16 plus
• 1 x 2 x 2 x 2 8 plus
• 0 x 2 x 2 0 plus
• 1 x 2 2 plus
• 1 equals 251

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Adding Two Numbers (Binary)

• 1010 2210 3210
• 1010
• 10110
• 100000
• 10 and 22 are data but what is the ?
• An instruction
• What is carrying?
• Storage

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Bits and Bytes and Words

• A bit is a single binary integer
• Can be on/true/1 or off/false/0
• A byte is 8 binary integers
• Between 11111111 1286432168421
• and 00000000
• Between 255 and 0
• A word is 2 bytes

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Bytes and Text Words
64
127
32

• Concept of the byte very useful for understanding
  text

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TEXT

• T 84 1100000
• E 69 1000101
• X 88 1110000
• T 84 1100000

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Meaning

• That such binary patterns as these can have
  meaning, is because standards have been agreed
• But a computer must know what data is what - how
  does it know that they are to be taken as text
  and not as numbers to be added?

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Markup

• Some methods of text representation have codes
  for italics, bold etc
• The most famous are HTML and RTF

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Text hierarchy
Characters are nothing more than numerical codes
but they are made meaningful by standards
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Representing Images

• A square
• If we are printing left to right the sequence is

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Monochrome Image

• We can be happy with dots
• newspaper
• computer screen
• television
• Color of the dot here either black or white (1
  bit color)

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Adding More Color

• 4 bit color (16 colors)
• red,green,white,blue,yellow,cyan,magenta,silver,tu
  rquoise
• 8 bit color (256 colors)
• a palette
• 24 bit color (all colors)

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Light Colour
White Light
Spectrum of colours
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Additive Primary Colours

• The eyes receptors are sensitive to red, green
  and blue

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Screen Resolution

• True colour resolution - 256 levels of Red,
  Green and Blue
• 256 x 256 x 256 16.7 million colours (RGB
  combinations)

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Hexadecimal Number System

• base number 16
• sixteen number values 0 1 2 3 4 5 6 7 8 9 A B C
  D E F

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Hexadecimal Number System (cont.)

• 251 FB (or FBh or 0xFB )
• 15 x 16 240 plus (F15)
• 11 equals 251 (B11)

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Hexadecimal and RGB

• RGB Colour Codes
• Red 255,00,00 FF0000
• Green 00,255,00 00FF00
• Blue 00,00,255 0000FF
• Yellow 255,255,00 FFFF00
• Cyan 00,255,255 00FFFF
• Magenta 255,00,255 FF00FF

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Compression

• A 24 bit (3 bytes) 100x100 pixel image requires
  300K disk space
• For transmission over the internet this would be
  impractical
• Methods of compresssion GIF, JPG, PNG

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Still image hierarchy
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Motion
Less images but faster frequency due to screen
refresh

• Motion
• We are happy with a series of still images
• Except when frequency too slow

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Sequence of Still Images

• Normal video 25 frames per second
• Too much even with compressed still images
• Further methods of compression
• MPEG, QuickTime

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Waveforms

• Light and Sound are examples of waves
• Amplitude
• Wavelength
• Speed

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Digitisation

• Process of converting analogue to digital
• continuous variation
• to limited sample
• Interpolation
• estimate the value
• almost as good as original
• our perception

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Sea of Information

• Text,Image,Movie,Sound,Animation
• Aggregated into Databases

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Editing Digital Information

• We dont merely want to view information but we
  want to change it, process it, retouch it, update
  it, analyse it
• We need programs adapted for particular uses

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What would we use for...

• Making a negative of a photo (and what would
  happen)
• Removing all occurences of 'color' and replacing
  it with 'colour' in a document
• Putting a new voiceover onto a video
• And how would we do these things?
• Think of a process which can now be done on
  computer compared with how it was done in the past

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The Computing Environment

• The computing environment is the ensemble of
  standards and practices which enable humans to
  manipulate data
• the ecology of computing- the digital food chain
• from bits and bytes to web pages and mp3