Computer Applications Mrs. Stern

1.The Vacuum Tube Years 2.The Era of the Transistor 3.Transistors on a Chip

 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

 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

Transistor Radio 1964 Transistor Beads Stem

 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

 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

A combination of: Hardware & Software

 Hardware – the tangible, physical equipment that can be seen and touched  Keyboard  Monitor  Printer  Computer chips

 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

 They perform FOUR basic functions: 1. Store data and programs 2. Function unattended due to its ability to interpret and follow instructions it is provided 3. Do arithmetic calculations 4. Perform logical comparisons

 It only has FOUR basic functions  Its tremendous speed  Its accuracy  Its ability to store vast volumes of data

In the computers memory: 1. Internal memory (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. 2. External memory (ex. DVD’s & hard drives)

Input device: hardware that permits the computer to accept data o Keyboard o A mouse o Bar-code scanner o Light pen o Touch display screen o Speech recognition device

Hardware which reports the information in a form we can understand monitor printer robots sound or music speakers

 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

 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)

 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

 BrainPop - Binary

Memory is measured in bytes 8 bits = 1 byte1000 bytes = 1 kilobyte (KB) 1000 kilobytes = 1 megabyte (MB)1000 megabytes = 1 gigabyte (GB)1000 gigabytes = 1 terabyte (TB)