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This overview explores the three generations of computers, detailing their evolution from bulky, unreliable vacuum tube systems to compact, high-speed microchip technology. Beginning with the vacuum tube era (1946-1958) exemplified by the massive ENIAC, the narrative transitions to the transistor era (1959-1964), where computers became faster and more reliable. Finally, we delve into the modern age of integrated circuits, highlighting the exponential growth in transistor density and computing power. Learn how hardware and software work together, the role of memory, and the importance of processors in today’s computing landscape.
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Understanding Computers Computer Applications Mrs. Stern
Computer History3 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 • 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
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
What it looked like 1964 Transistor Beads Stem Transistor Radio
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
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
What are computers made of? A combination of: Hardware & Software
What is Hardware? • Hardware – the tangible, physical equipment that can be seen and touched • Keyboard • Monitor • Printer • Computer chips
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
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
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
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)
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
Output Devices Hardware which reports the information in a form we can understand • monitor • printer • robots • sound or music speakers
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
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)
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
Binary System • BrainPop - Binary http://www.brainpop.com/
Computer Memory Memory is measured in bytes