A serie of computer instructions are needed to perform a complex task
(There are tons of different computer programs... and the number is growing...)
Sophisticated programs require teams of highly skilled programmers and other professionals
As a result of the execution of an instruction, the CPU can modify the memory, read data from input devices or send data to output devices
RAM is very fast memory and is relatively expensive (compared to hard disk).
Modern PC has 512 M (512,000,000) to 1 G (1,000,000,000) bytes (memory units) of memory. Super computers can have several hundreds of GBytes of RAM
Examples: keyboard, mouse, scanner
Examples: monitor, printer
These I/O devices are usually storage devices that the computer uses to store longer term information (e.g., database)
This information super high way is called the computer bus system or bus for short
NOTE: when computer scientists talk about busses; they do NOT mean motor vehicles !!!
The communication pathway interconnect the components and allow the components to exchange electrical signal (that's how electronical devices communicate with each other).
If you take a look at the Interstate highway; you will see that there are traffic rules imposed on the highway system to make things run smoothly.
Similarly, there are "rules" implemented on the system bus to allow the different devices to use the bus without getting in each other way...
In technical terms: there are circuitry (bus controllers) that control the use of the computer bus.
Look around the wall... Yep... that's the ENIAC...