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Understanding Computers

Understanding Computers. Computer Applications Mrs. Stern. Computer History 3 Generations of Computers. The Vacuum Tube Years The Era of the Transistor Transistors on a Chip. The Vacuum Tube Years (1946-1958). Computers were: Huge Slow Expensive Often undependable

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Understanding Computers

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  1. Understanding Computers Computer Applications Mrs. Stern

  2. Computer History3 Generations of Computers • The Vacuum Tube Years • The Era of the Transistor • Transistors on a Chip

  3. The Vacuum Tube Years (1946-1958) • Computers were: • Huge • Slow • Expensive • Often undependable • ENIAC was built in 1946 • 18,000 vacuum tubes • Took up a lot of space • Gave off a lot of heat Cooled down by a gigantic air conditioner & still overheated regularly

  4. ENIAC Electronic Numerical Integrator and Calculator

  5. The Era of the Transistor (1959-1964) • Transistor was like the vacuum tube only better: • Faster • More reliable • Much smaller • Cheaper to build • Gave off virtually no heat • 1 transistor replaced 40 vacuum tubes

  6. What it looked like 1964 Transistor Beads Stem Transistor Radio

  7. Transistors on a Chip (1965-current) • With the invention of Integrated Circuits or Microchip, thousands of transistors fit into one microchip • The number of transistors that fit onto a chip doubled every two years • Today: Millions per microchip

  8. Computers today can: • Carry out instructions in billionths of a second • Are sometimes the size of a watch • Since electricity travels 1 foot in a billionth second • The smaller the distance the faster the speed

  9. What are computers made of? A combination of: Hardware & Software

  10. What is Hardware? • Hardware – the tangible, physical equipment that can be seen and touched • Keyboard • Monitor • Printer • Computer chips

  11. What is software? • Software – the intangible instructions that tell the computer what to do • PowerPoint • Windows XP • Sims City • Oregon Trail • Programmers – write the instructions that tell the computer what to do

  12. Computers are Simple Devices • They perform FOUR basic functions: • Store data and programs • Function unattended due to its ability to interpret and follow instructions it is provided • Do arithmetic calculations • Perform logical comparisons 

  13. What makes it such a powerful device? • It only has FOUR basic functions • Its tremendous speed • Its accuracy • Its ability to store vast volumes of data

  14. Where are the instructions stored? In the computers memory: • Internalmemory (ex. microchips) • RAM(random-access memory) This is temporary & can be erased. (ie: Microsoft Office Xp, Internet Explorer) • ROM (read-only memory) - This is permanent & can not be changed or erased. • Externalmemory (ex. DVD’s & hard drives)

  15. Input & Output Devices Input device: hardware that permits the computer to accept data  • Keyboard • A mouse • Bar-code scanner • Light pen • Touch display screen • Speech recognition device

  16. Output Devices Hardware which reports the information in a form we can understand • monitor • printer • robots • sound or music speakers

  17. Processors • Is the computer chip that receives & carries out the instructions from the software • All computers big & small have processors also known as Central Processing Units or CPUs • Referred to as brains of the computer

  18. Functions the processor performs: • Receives & temporarily stores instructions & data to be processed • Moves & changes stored data • Arithmetic calculations • Makes decisions of logic (ex: determines if two numbers are equal)

  19. External Storage • They hold data outside the memory of the computer. • They connect to the computer & are under the control of the processor at all times • Most common: • USB Flash Drive • External hard drives • CD/DVD

  20. Binary System • BrainPop - Binary http://www.brainpop.com/

  21. Computer Memory Memory is measured in bytes

  22. You should NOWunderstand computers

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