Computer Merit Badge History of Computers
History of Computers Abacus
History of Computers John Napier’s Bones
History of Computers Herman Hollerith Punched card
History of Computers • University of Pennsylvania Eniac
History of Computers Dr. J. Presper & Dr. John Mauchly UNIVAC
History of Computer Vacuum Tubes
History of Computers John Bardeen, Walter Brattain, and William Shockley: Transistors
Types of Computers Special Purpose Watch GPS General Purpose Office computer Home computer
Types of Computers Supercomputers Cray Mainframes HP 8000, AS 400 Minicomputers obsolete Microcomputers Desktop, Laptop, PDA
Parts of a Computer Central Processing Unit CPU Input Device Keyboard, Mouse, Scanner, Microphone Storage Unit Floppy Disk, Hard drive, Tape BU, CD Output Device Monitor, Printer, Modem, Network Card
Memory • Ram – Random access memory is the working area or scratch pad for the computer measured in Megabytes. • Rom – Read only memory is the unchangeable instruction set that wakes up the computer. Bootstrap, reboot, boot. • Hard drive storage - Filing cabinet where programs are stored till called into action. Measured in Gigabytes.
Understanding Data Binary number system 00001001 = 9 One digit is one bit 8 bits make a byte Kilobyte is 210 or 1024 bytes Megabyte Gigabyte Terabyte
ASCII American Standard Code for Information Interchange A special code corresponding to the numbers 0 through 255 Character ASCII Code Binary Number $ 36 00100100 Open Word and type Alt 36 Text files -. txt, . doc, . wp
Monitors • Pixels are dots of red, green and blue phosphor on the screen that glow when struck by electrons. • 24 bit true color will produce 16. 7 million different colors; the maximum the human eye can see. • Picture files -. mpg, . gif, . jpg, . pct
Sound • Computers store sound by sampling the sound wave at very fast intervals and assigning values of pitch, tone, and amplitude to the sample. • Sound files -. au, . wav, mp 3
Software • Software is a set of instructions that tells the hardware what to do. • Operating systems – DOS, Windows 95, 98, ME, XP, Linux, Unix, Mac OS • Applications – Word, Excel, Access, Doom, Quake, Space Invaders • Programming Languages – C++, Java, HTML, FORTRAN, Pascal, COBOL, Basic • Open Word – Alt F 11 Visual Basic Editor
Applications • Graphics – paint, CAD • Computer Generated Animation – Shrek • Sound programs – MIDI, Real Audio, Windows Media Player • Communications programs – Telnet, Hyper Terminal, Remote Desktop, PC Anywhere, emulators
Programming • Programming languages convert instructions humans understand (source code) into binary machine code that the computer understands (object code). • Machine code cannot port to another machine unless it is identical. • A Compiler program is written for each type of computer so programs can be ported.
Communications Networks • Modems – change digital to analog for phone line use. • DSL – Digital Subscriber Line • Cable “Modem” – Router • Satellite • Wireless – 802. 11, wifi, bluetooth, infrared
Computers at Work Electrical engineer – design hardware Programmers – write instruction code Network engineer – design & run networks Technicians – troubleshoot hardware and assist users with software issues Graphic designers – create commercial art and film Robotics – remote control of machines
Copyrights • Books, movies, music, software and pictures are copyrighted by the authors or publishers. Copies cannot be created without special permission or fee. • Shareware – test drive for free, pay if you keep it. • Public Domain software – free to use and copy. GNU, Freeware, Copyleft.
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