Feb 15, 2016
Understanding ComputersComputer ApplicationsMrs. SternComputer History3 Generations of ComputersThe Vacuum Tube YearsThe Era of the TransistorTransistors on a Chip
The Vacuum Tube Years (1946-1958)Computers were:HugeSlowExpensiveOften undependableENIAC was built in 194618,000 vacuum tubesTook up a lot of spaceGave off a lot of heatCooled down by a gigantic air conditioner & still overheated regularly
The first began in 1946-1958 (The Vacuum Tube Years) these computers were huge, slow, expensive, and often undependable. In 1946 the ENIAC was built. The ENIAC used 18,000 thousand vacuum tubes, which took up a lot of space and gave off a great deal of heat just like light bulbs do.The ENIAC gave off so much heat that it had to be cooled by gigantic air conditioners. However, even with these huge coolers, vacuum tubes still overheated regularly. It was time for something new.
3ENIAC Electronic Numerical Integrator and Calculator
The Era of the Transistor (1959-1964)Transistor was like the vacuum tube only better:FasterMore reliableMuch smallerCheaper to buildGave off virtually no heat 1 transistor replaced 40 vacuum tubes
The Second Generation: 1959-1964 (The Era of the Transistor) did not last as long as the vacuum tube computer lasted, but it was no less important in the advancement of computer technology. The transistor which functioned much like a vacuum tube in that it can be used to relay and switch electronic signals was obviously different in many ways. The transistor was faster, more reliable, much smaller, and much cheaper to build than a vacuum tube. They also gave off virtually no heat. One transistor replaced the equivalent of 40 vacuum tubes. 5What it looked like
Transistor Radio1964 Transistor Beads StemTransistors on a Chip (1965-current) With the invention of Integrated Circuits or Microchip, thousands of transistors fit into one microchipThe number of transistors that fit onto a chip doubled every two years
Today: Millions per microchip
The Third Generation: 1965-current (Transistors on a chip). Transistors were a tremendous breakthrough in advancing the computer. However no one could predict that thousands even now millions of transistors (circuits) could be compacted in such a small space of silicon. Since the invention of integrated circuits, the number of transistors that can be placed on a single silicon chip has doubled every two years, shrinking both the size and cost of computers even further and further enhancing its power. 7Computers today can:Carry out instructions in billionths of a secondAre sometimes the size of a watchSince electricity travels 1 foot in a billionth secondThe smaller the distance the faster the speed
These third generation computers can carry out instructions in billionths of a second. The size of these machines dropped to the size of a watch, since electricity travels about a foot in a billionth of a second, the smaller the distance the greater the speed of computers
What are computers made of?
A combination of:Hardware & Software
What is Hardware?Hardware the tangible, physical equipment that can be seen and touchedKeyboardMonitorPrinterComputer chips
What is software?Software the intangible instructions that tell the computer what to doPowerPointWindows XPSims CityOregon Trail Programmers write the instructions that tell the computer what to do
11Computers are Simple DevicesThey perform FOUR basic functions:Store data and programsFunction unattended due to its ability to interpret and follow instructions it is provided Do arithmetic calculationsPerform logical comparisons
What makes it such a powerful device?
It only has FOUR basic functionsIts tremendous speedIts accuracy Its ability to store vast volumes of data
Where are the instructions stored?In the computers memory: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.External memory(ex. DVDs & hard drives)
Input & Output DevicesInput device: hardware that permits the computer to accept dataKeyboard A mouseBar-code scannerLight penTouch display screenSpeech recognition device
15Output DevicesHardware which reports the information in a form we can understandmonitor printerrobots sound or music speakers
ProcessorsIs 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 CPUsReferred to as brains of the computer
All computers do processing by following a series of instructions in a software program. The computer chip that receives and carries out these instructions is called the processor. All computer systems, regardless of size or manufacturer, have processors (also referred to as central processing units or CPUs). The CPU is often referred to as the brains of the computer system.
17Functions the processor performs:Receives & temporarily stores instructions & data to be processedMoves & changes stored dataArithmetic calculationsMakes decisions of logic (ex: determines if two numbers are equal)
The processor performs many different functions. It receives and temporarily stores instructions as well as the data to be processed. It moves and changes stored data. It does arithmetic calculations. It makes decisions of logic, such as determining if two numbers are equal. It directs the action of the input and output devices. The CPU is often referred to as the brains of the computer system.
They hold data outside the memory of the computer. They connect to the computer & are under the control of the processor at all timesMost common:USB Flash Drive External hard drivesCD/DVD
Nearly all general-purpose computers include the ability to connect to additional storage devices that hold data outside the memory of the computer. These additional storage devices are known as external storage. Externalstorage devices are on-line to the computer; that is, they are connected directly to the computer. They are, therefore, under the control of the processor and can be used at all times. The most common form of external storage is a thumb drive (aka... USB flash drive).Other forms of external storage include;Hard drives CD/DVD (recordable) drives. A flash drive can hold between 256 MB (megabytes) to 8 GB (gigabytes) of memory where one CD can store 700 MB (megabyte). A single layer DVD can hold 4.7 GB (gigabytes of memory). Hard drives can hold even more. Most hard drives hold between 60 GB (gigabytes) to 1000 GB (or 1 terabyte). 19
Binary SystemBrainPop - Binaryhttp://www.brainpop.com/
Computer MemoryMemory is measured in bytes
Computer memory is measured in bytes. A single byte is made up of a series of 1's and 0's normally traveling in pairs of eight. These eight 0's and 1's are the way the computer communicates and stores information. With each keystroke or character a byte of memory is used.
You should NOWunderstand computers
Any questions?? Something you did not understand????22