Introduction to computers The computer Internally The connections

Introduction to computers

The computer

Internally

The connections

RAM/ROM Memory mapping Address Values 10111001 00001111 0001 11100011 0002. . . . FFFF 00100100 • Size reminder: • • • Kilobyte Megabyte Gigabyte Terabyte Petabyte … Kb Mb Gb Tb Pb 210 ~103 220 ~106 230 ~109 240 ~1012 250 ~1015

HD/DVD track sector head

Display • • Screen pixel or dots Color coding: 32 bits 1 pixel = 3 bytes of color (RGB)+1 byte alpha channel (transparency) 1600 x 1200 x 4 bytes=7, 5 Mb! • Fonts w Bitmap w Vectors § True. Type, Open. Type, Post. Script

Keyboard/Mouse • Each key (or combination • The mouse movements of keys) of the keyboard w 1 to 4 bytes (vertical & horizontal) sends a code to the computer. • Buttons w Clicked, pressed, rolled • The code is interpreted and converted to the buttons corresponding ASCII or Unicode number.

File systems • What exactly is a file? w a piece of information (text, graphic, data, music program, script) w it is identified by a name and an logical address (or path) w other informations: date, size, type, creator, ownership, physical address…

File system organisation Disk 1 Disk 2 C: DOCS Disk 2 D: PROGS WORD EXCEL CONFIG / Directories DATA EXPT 1 EXPT 2 Disk 1 Subdirectories /usr local phil lib bin emacs Windows /home Unix X 11 john

Path • The path is the logical address used by the system or the user to locate a file. • Example: D: /Deepak/Computer. System/Dupont_ Jean. txt path filename suffix

File types • Executable w. exe w. app • Data w w w Text (. txt) Music (. mp 3) Image (. jpg, . gif) Movie (. mpg, . mov) Binary (. bin)

Networks • Direct w USB 11 Mb-480 Mb w Ethernet 10 Mb-1 Gb • Wired w Modem 56 Kb w ADSL 600 Kb-8 Mb w LAN 10 Mb-10 Gb • Wireless w Bluetooth 1 Mb-20 Mb w WIFI (Air. Port) 11 Mb-54 Mb