Transcript Session 5 KS3 – How the CPU works

Structure of a computer
KS3 Curriculum
• Computers are devices for executing programs
• Not every computer is obviously a computer (most
electronic devices contain computational devices)
• Basic architecture: CPU, storage (e.g. hard disk, main
memory), input/output (e.g. mouse, keyboard)
• Computers are very fast, and getting faster all the time
(Moore’s law)
• Computers can ‘pretend’ to do more than one thing at
a time, by switching between different things very
quickly
Not every computer is obviously a
computer
• Not every computer is obviously a computer
(most electronic devices contain
computational devices)
• Students can research how many devices they
can find that contain a microprocessor.
Devices that contain a microprocessor
Personal
phones
watches
calculators
computers and laptops
cameras
iPods (iPads, other mp3 players, etc.)
WII and X-boxes
Computers:
infrared keyboards and mice
disk drives
switches
hubs
Commercial devices:
cash tills
supermarket bar code scanners
vending machines
lottery ticket dispensing machines
printers
faxes
copiers
automatic door openers
credit card processors
ATM machines
Industry
vehicles (cars, airplanes, boats, trains,
trucks, etc)
navigational systems (tomtom, loran, etc)
Home:
clock/radios
ovens
microwave ovens
washing machines
driers
stereo systems
TVs
DVD players
satellite/cable boxes
thermostats
air conditioners
motion detectors
smoke detectors
burglar alarm systems
Medical:
pace makers
insulin auto-injectors
heart monitors
hearing aids
Military:
smart bombs
missiles
guns
turrets
tanks
sonic guns
Police:
radar guns (for speeding tickets)
infrared motion and camera
systems (for traffic lights)
uv locators (finding suspects and
bodies)
lie detectors
Municipal devices:
traffic lights
walkie-talkies
train ticket purchasing machines
Computers are devices for executing
programs
When a program runs on a computer the
processor repeatedly fetches and executes the
next instruction from main memory, one at a
time.
http://www.intel.com/content/www/us/en/education/k12/the-journeyinside/explore-the-curriculum/microprocessors/lesson2.html
Human CPU Activity
• Students can do a physical demonstration of the
CPU operation. Get students to play the roles of:
•
•
•
•
1. Processor
2. Clock
3. Main memory registers (number them 1 to 6)
5. A bus that transfers data from the Processor
to main memory
Human CPU Activity
• Write some increasingly difficult mathematical equations on pieces
of paper e.g. 4+1, 7+9, 12+103, 45/5, 12^2, 9*4*5
• Give a piece of paper to each student who is a piece of main
memory.
• To start the processor give the clock a watch with a second timer.
Tell them to instruct the processor to fetch an instruction from main
memory every 20 seconds. The processor must use the bus to get
the instructions from one memory register at a time and work out
the answer before the 20 seconds are up.
• Clock speed can them be increased (10 seconds, 5 seconds etc.) to
see the result on the processor.
Extension tasks
• Make the clock tick faster – a real clock ticks at
3Ghz
• Make the calculations more complex – then you
can use an extra student be a dual core processor.
It can be easier if difficult work is shared.
• Simulate saving to the hard disk by having on
area of memory much further away and harder to
get to than the others.
• Simulate a cache by having one student stand
next to the processor and remember repeated
calculations.
Extension tasks
• Use the how computers work instructions to
draw images that could appear on the screen
Doing a million things at once
Do you have any applications running at the
same time?
• music playing
• streaming video
• e-mail sending/receiving
• gaming
• writing
• … at the same time…
Activity
• Use the workshop activity materials
Moore's law
• Moore's law is the observation that over the
history of computing hardware, the number of
transistors on integrated circuits doubles
approximately every two years.
• Historic timeline
• http://www.intel.com/content/www/us/en/hi
story/historic-timeline.html
Processors into the future
• Today’s high-end computer chips have as
many as 16 cores. But Tilera’s top-of-the-line
chip has 100.
http://www.wired.com/wiredenterprise/2012
/01/mit-genius-stu/
• http://blogs.howstuffworks.com/2011/04/20/
how-fast-is-the-fastest-microprocessor-chipnow-and-in-the-future/
Starters/Plenaries
• Youtube Starter: From sand to chip - How a
CPU is made
• http://www.youtube.com/watch?v=GQmtITMdas
• Other Intel videos
• http://www.intel.com/content/www/us/en/e
ducation/k12/the-journey-inside/explore-thecurriculum/microprocessors.html
Starters/Plenaries
• Get students to look at PC adverts on the
internet to see who can find the fastest
processor.
• http://ark.intel.com/products/family/41877/I
ntel-Pentium-Desktop-Processor
Summary