5 ٥ V new position

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10 ^1 10 ^2 10 ^ : : : : : : 8 2 ^1 2 ^2 2 ^3 2 ^4 2 ^7 :

byte bit 1 byte = 8 bits = 2 ^8 = 256 (from 0 to 255) 1 Kilobyte = 1024 bytes 1 Megabyte = 1024 Kilobytes 1,048,576 bytes 1 Gigabyte = 1024 Megabytes 1 Terabyte = 1024 Gigabytes

decimalhexadecimalbinary A B C D E F1111 decimalhexadecimalbinary F FF

# bytesnamerange 1BYTE0 to 255 (short unsigned) 1SHORT SIGNED-128 to +127 (short integer) 1LOGICALTrue or False (1 or 0) (boolean) 2INTEGER-32,768 to +32,767 (integer x 2, integer signed) 2INTEGER UNSIGNED0 to 65,535 4LONG INTEGER-2,147,483,648 to +2,147,483,647 (integer x 4) 4REAL-1 x to +1 x (7 decimals) (real x 4, single precision) 8REAL x 216 decimals (real x 8, double precision) anySTRINGany combination of characters (character)

Non-Printable CharactersPrintable Characters Decimal: Hex: Decimal: Hex: Character:SOHDC1!1AQaq Decimal: Hex: Character:STXDC2"2BRbr Decimal: Hex: Character:ETXDC3#3CScs :::: ASCII table (top)

ASCII vs. binary

E+20 real 1,819,632,481 long integer 27,76525,441 integer byte ? ? ? ? string ?

The operating system

DOS (to 6.22) workstation personalserver 1993 NT Win 3.1 Win 95 Win 98 Win ME NT 3.51 NT XP home serverws serverpro serverpro serverws 1985 Win 1.0 Vista Win Win 8

The operating system

Free Software Richard Stallman Linus Torvalds

The Free Software Foundation –Four fredooms 0: freedom to run the program, for any purpose 1: freedom to study how the program works, and change it so it does your computing as you wish 2: freedom to redistribute copies so you can help your neighbor 3: freedom to distribute copies of your modified versions to others; by doing this you can give the whole community a chance to benefit from your changes –Access to the source code is a precondition for #1 and #3 Free Software

The GNU Project was launched in 1984 to develop the GNU system. The name “GNU” is a recursive acronym for “GNU's Not Unix!” A Unix-like operating system is –a software collection of applications, libraries, and developer tools, –plus a program to allocate resources and talk to the hardware, known as a kernel GNU is typically used today with a kernel called Linux. This combination is the GNU/Linux operating system Free Software

The GNU General Public License (GNU GPL or GPL) is the most widely used free software license, which guarantees end users (individuals, organizations, companies) the freedoms to use, study, share (copy), and modify the software The GPL is a copyleft license, which means that derived works can only be distributed under the same license terms In 2001, Microsoft CEO Steve Ballmer referred to GPL as "a cancer that attaches itself in an intellectual property sense to everything it touches“ The term “Open source” was introduced at the end of 90s to avoid the idea of something that is not suitable for corporate use, due to its being available at no monetary cost Free Software

There are not only laptops and mobiles around the world... Free Software Web servers market share (active sites) – september 2015

Free Software

Example of business models dual-licensing selling of support, training, consulting and other services selling software as a service partnership with funding organizations voluntary donations bounties pre-order/crowdfunding model advertising-supported software selling of optional proprietary extensions selling of required proprietary parts of a software product re-licensing under a proprietary license obfuscation of source code delayed open-sourcing etc. Free Software

Where we find it the Internet backbone: routing, DNS, web servers, mail servers, firewalls operating systems: Linux (and Android) office suites: OpenOffice, LibreOffice web clients: Firefox and Thunderbird graphics: Gimp databases e.g. MySQL, PostgreSQL geomatics, e.g. QGIS, Grass, gvSIG, Mapserver, GDAL etc. have a look to Free Software