ELECTRONIC/COMPUTER AGE

1. ELECTRONIC/COMPUTERAGE

2. Integrated Circuits • Integrated circuits have become more and more complex. One measure of their complexity is the number of transistors they use • SSI – Small Scale Integration : several dozen transistors • MSI – Medium Scale Integration : up to several hundred transistors • LSI – Large Scale Integration : up to several thousand transistors • VLSI – Very Large Scale Integration : one hundred thousand or more transistors

3. Computers • The first mechanical adding machine was invented by Pascal in 1645 • The first calculator was developed in the mid-1800s by Charles Babbage • Ada, Babbage’s co-worker was the first computer programmer • Hollerith devised a way of automating the Census. It had a • Machine to punch the cards (input) • Tabulator for sorting the cards (processing) • Counter to record the results (output) • Sorting box for rearranging the cards reprocessing (feedback) • In 1911, Hollerith’s company became a part of IBM, the largest computer company in the world today • ICs brought computers into household use • Microcomputers are used home appliances, electronic games and automobiles

4. Computers System • A computer under program control works on a list of instructions called a program • Information is represented by 0s and 1s in today’s computers --- binary digits or bits • Any decimal number can be represented by a binary number and vice versa • A group of eight bits are called byte. Data can be represented by kByte, MByte and GByte • Computer Processor • It reads the program and changes the instructions into actions • The power of a processor refers to how fast it is --- MIPS

5. Computer Systems • Memory • A tiny chip can store more than one million characters • A RAM stores the program and information currently being worked on --- primary storage • A secondary storage stores information for later use --- floppy, hard disk and magnetic tape • Writing to disk --- magnetizing tiny bits of iron oxide on a magnetic tape through a head (an electromagnet) • Reading from disk --- changing the magnetic fields back to electrical impulses • Compact disks can store audio, video files in billions of bytes or GBs

6. Computer Systems • Input • Information provided to a computer is called input • Different forms can be keyboard, hard disks, floppy disks, optical character reader and human speech • Others can be mouse, light pen and touch-sensitive screen • Output • Video monitor or CRT screen, printer, plotter, audio and video • A combination of keyboard and monitor is called a terminal • Printers --- dot matrix, daisy wheel, laser • Music and voices can be made in a computer using a synthesizer • Voice synthesizers reproduce speech --- telephone messages • Data communication --- connecting computers to each other • Modems --- modulation and demodulation

7. Computers, Large & Small • Computers come in different sizes with different memory space, processor speeds etc • Microcomputers • Found in appliances, automobiles, PCs • They can be 8-bit, 16-bit or 32-bit machines • Minicomputers • Slightly larger than microcomputers and are shared by several people in a company • They handle 16, 24, 32, or more bits at a time

8. Computes, Large & Small • Mainframe Computers • Used by universities and government agencies and large companies • They are used to make payroll checks, warehouse records etc • They carry out millions of instructions per second • Supercomputers • The fastest and the largest computers and are most often used for research • Its speed is measured in floating point operations per second or FLOPS and GFLOPS • The power of supercomputer twenty years ago is now available on a desktop PC