Hardware

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Hardware

• ITGS

2
Hardware definition

• Computer and network equipment consisting of
  transistors, circuit boards, wiring, connectors,
  disk drives, cables, and similar physical or
  tangible components.

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Computer System

• INPUT
• PROCESS (CPUCentral Processing Unit)
• OUTPUT
• STORAGE

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Input devices

• Keyboard
• Mouse / Joystick / Trackball
• Scanner / Digital Cameras
• Game devices (Flight simulator / Car racing)
• Optical pencil Bar code readers
• Specialized meters
• Thermometers
• Barometers
• Special compound detector
• Infrared detectors
• Microphone
• Read only storage devices (CD-ROM)
• Magnetic ink character readers

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Output devices

• Monitor
• Printer
• Plotters
• CAM devices (circuit printers, textile machines,
  etc)
• Speakers

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Input/Output devices

• Touch screen monitors
• Modems Network Interface Cards
• Sound Cards
• Video Editing Cards
• Most storage devices (HDD, FDD,etc) except read
  only devices like the non recordable CD-ROM
  device.
• VR Goggles

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Secondary Memory Storage devices

• Floppy disk drives (FDD)
• 3 ¼ inches
• 5 ½ inches
• Hard disk drives (HDD)
• Zip drives
• Jaz Drives
• Tape back-up drives (TBD)
• Optical disks (CD-ROM, CD-RW, CD-R)
• Other (magnetic strips or chips, bar codes, OCR,
  punched cards and punched paper strips.

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Primary Memory Storage Devices

• RAM Random-access memory
• Volatile memory (need to be powered)
• You can store whatever you want wherever you want
  (you choose at random).
• Temporary memory
• SRAM, DRAM, SDRAM
• ROM Read Only Memory
• Used to store start-up/boot programs
• You cannot modify it
• PROM, EPROM,EEPROM,FLASH ROM

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Memory devices

• Primary Memory (RAM, ROM)
• Secondary Memory (HDD, FDD, etc)

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Keyboard

• QWERTY standard (French AZERTY, GermanQWERTF)
• Made to type slow (for old typewriters)
• Expanded or not expanded
• 101-112 keys

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Monitors

• Cathode Ray Tubes
• Cheapest
• Produce heat and dangerous radiation
• Liquid Crystal Display (LCD Panels)
• No radiation
• Fragile
• You have to look at them from the front
• More expensive
• Active matrix
• Very expensive
• Perfect resolution
• Little harm to eye-sight
• No radiation

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Printers

• Daisy wheel
• Works like a typewriter
• Very old and slow
• Dot-matrix
• Slow
• Noisy
• Ink tapes are cheap
• Low resolution
• Ink jet
• Good resolution
• Cheap to buy but expensive ink cartridges
• Relatively fast
• Laser
• Expensive
• Very fast
• Excellent resolution

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Bytes, Megas, Gigas

• The smallest unit of information in a computer is
  a BIT (Binary Digit). It can take only two values
  1 or 0. (A bit may mean true or false, on or off,
  male or female, etc.)
• 1 byte 8 bits (in a standard computer)
• 1 KB 1024 bytes 210 bytes (Kilobytes)
• 1 MB 1024 KB 220 bytes (Megabytes)
• 1 GB 1024 MB 230 bytes (Gigabytes)
• 1 TB 1024 GB 240 bytes (Terabytes)

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Comparing storage devices

• CD-ROM
• Read-only
• Very portable
• Slower than HDDs
• Big capacity (640 Megas)
• Cost around 2 dollars
• They can get picked specially the RW-CDs
• Magnetic tapes
• Used for backups
• Very portable
• Very slow
• Not very vulnerable

• Floppy disks
• Very portable
• Little capacity (1.4 mega)
• Very cheap
• Quite slow
• Very vulnerable
• Hard Disks
• Very fast
• Lots of capacity (15 gigas)
• Not portable
• Cost around 100 dollars
• Not very vulnerable

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Hardware specifications

• IBM Compatible/ Not Compatible
• Processor (Pentium III 500MHz)
• RAM (example 64 MB)
• HDD Space (example 15 GB)
• CACHE (Example 128 KB)
• Modems
• May work only for a given Operating System
• Speed measured in KB/s, bauds, bps, cps
• Ports
• Serial (mouse, modem)
• Parallel (printer, scanner)
• USB (video cameras, musical devices,etc)
• Network port
• Slots (soundcards, modems, video-editors,etc)
• CD ROM (speed measured as X44, where the number
  44 means how much faster is this device than the
  first one by Phillips.

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Processor

• IBM Compatible/ Not Compatible
• Speed (example 500 MHz)
• Kind
• INTEL (80386,80486,80586,Pentiums, etc)
• SPARC
• With/Without Arithmetic Co-processor
• Number of bits to address (16, 32, 64)
• CISC Complex Instruction Set Computer
• Machine language includes lots and complex
  instructions. Example Intels Processor
• RISC Reduced Instruction Set Computer
• Machine language includes few and simple
  instructions. Example SPARC, Macintosh
  Processors

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RISC and CISC

• RISC Reduced instruction set computer.
  Processor chip using a reduced set of
  instructions but executing them at high speed.
  These chips contain most commonly used
  instructions and pass requests for others to
  external chips. Typical RISC chips provide high
  performance at low power consumption.
• RISC are proved better than CISC. But technology
  is growing so fast that they have always
  comparable efficiency.

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Flow of data when executing an application

• Usually when you run an application (i.e. Word)
  you copy the entire executable file from the HDD
  into the RAM. Computers cannot execute a program
  directly from the HDD nor execute a program that
  is larger than the RAM.

LOAD
RUN
RUNNING PROGRAM
RAM
HDD
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CACHE Memory

• It is a very expensive and high speed memory that
  replicates the section of the memory currently
  being used.
• It is based in the principle of locality which
  says that it is more probable that the next line
  of a program will be near (in the RAM) of the
  current one.

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Good Practice

• Regular saving
• Make back-up (different names)
• Passwords
• Avoid excessive sun heat exposure
• Care for the computer
• Anti-virus
• Avoid executing, installing downloading
  untrusted programs
• Be critical on the origin of things found on the
  internet or other material (fake tutorial
  software)
• Buy on trusty computer companies, they may have
  components that are not the ones promoted.
• Think the real needs when buying a computer.
• Be aware of the risks of buying through the
  internet.

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Ergonomics

• Definition The designing of equipment to
  increase productivity and reduce user fatigue or
  discomfort.
• Health issues for over-exposure to computers
• Monitor radiation
• Sound pollution
• Repetitive Strain Injury (RSI)
• Eye-sight harm
• Back-bone problems

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Recommendations
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To take into account

• Choose ergonomic equipment
• Create a healthy workspace (Setup the correct
  position)
• Rest your eyes (Take breaks, Blink frequently)
• Listen to your body

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Repetitive Strain Injury

• Includes a variety of hand and wrist problems
  (like the carpal tunnel syndrome) which cause
  pain in the wrist, hand and arm due to repetitive
  forceful and/or awkward motion.
• The number of people with RSI is increasing
  (doubled from 80s to 90s)
• So did the number of lawsuits against employers!
• Can cause extreme pain and may prevent people
  from opening a door, shaking hands and ordinary
  tasks. It can even make people loose their jobs
  because of their disability.
• Carpal tunnel syndrome damage to a nerve in the
  hand and can result in numbness in the fingers
  and eventually in permanent disability.
• To read senior.british.edu.uy/it_dept/itgs/RSI.pd
  f

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Environmental Concern issues

• Energy consumption
• Hardware disposal
• This is a topic for class research

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Social Significance of Greater Dependence of
Computers at Work

• Reading Chapter 8 Gift of Fire
• Topics
• Computers and Unemployment
• Income and productivity
• Comparing with other technologies
• Teleworking
• Employee monitoring