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Computer Numbers (continued). Binary Numbers. Based on 0 and 1 Bi nary Digi t bit Place values of bits powers of 2 Bits grouped in Bytes. Binary Numbers. 10110101 Easier as 2 four-bit nibbles in Hexadecimal 0-9, A-F Commonly used in programming, web colors. Computer Numbering.
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Binary Numbers • Based on 0 and 1 • Binary Digitbit • Place values of bits powers of 2 • Bits grouped in Bytes
Binary Numbers • 10110101 • Easier as 2 four-bit nibbles in Hexadecimal • 0-9, A-F • Commonly used in programming, web colors
Computer Numbering • Word Number of bytes computer handles in one operation • Describes the processor • Limits address space • Limits size of numeric values • Early PCs were 8bit, now 64bit
Multipliers • Kilo • Mega • Giga • Tera • Peta
Really Big Numbers • 264 ≈ 18.45 quintillion • 18.45 * 1018 • Why do computer boxes lie? • 200GB hard drive 186GB ????
Speed • Measured in Hertz (Hz) • KHz • MHz • GHz • Speed at which CPU “ticks”
Comparing Speed • Not always directly comparable • Streamlined instructions • Pipelining • Multicore • Original IBM PC, 1981 – 4.77MHZ • Today’s screamer – 3.2GHz hexcore • 680x the clock, way more improvement
Using Windows The Operating System 16 January 2013
Define Operating System • Programs that control computer • Allocate resources • Control scheduling • Allow access to peripherals • Enforce security • Provide user interface
What OSs Available • Windows XP • Home, Pro • Media Center, Tablet • Vista/Win7/Win8 • Home/Home Premium • Business/Ultimate • Mac OS X • Linux – many distributions