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4/7/2012 Learning Objectives Chapter FOUR S y s t e m U n i t Reference: Shelly Cashman, Discovering Computers 2011, Living In Digital World, International Thompson Publishing, •Identify and describes components of system unit. •Describes the function of ALU and control unit. •Describes the machine cycle. •Describes types of RAM, Ports, Connectors of computer system. The System Unit The System Unit What is System Unit? Processor chips The hardware unit that houses a computer’s processor, memory chips, ports, and add-in boards Microprocessor- the smallest type of processor, with all of the processing capabilities of the Control Unit and ALU located on a single chip Processor chips Memory chips Ports…show more content…
MEMORY 4 4/7/2012 Data Representation 1 0 1 0 Data Representation Analog Signal 1 1 1 Digital Signal 0 0 0 Analog – Human speech; it consists of continuous signals that vary in strength and quality. Digital – an electronic signals powered by electricity which only appear in two discrete states: ON(1) or OFF(0) Data Representation IICSA CSA IIIICSA Data Representation CIIDCBE C DCBE CIDCBE 11110000 11110001 11110010 11110011 11110100 11110110 11000001 11000010 11000011 11000100 11000101 01011010 01111111 01111011 00110000 00110001 00110010 00110011 00110100 00110101 01000001 01000010 Extended Binary Coded Decimal Interchange Code (EBCDIC) – used widely on mainframe computers. 01000011 01000100 01000101 00100001 00100010 00100011 The Memory RAM (Random Access Memory) Volatile Memory – TWO When computer power of types is turned off, volatile memory memory losses its content VOLATILE (RAM) •Files remain in RAM when the computer is running. •Most RAM is volatile. •Loses its contents when the power is off. Non Volatile Memory – NON It doesn’t lose its content VOLATILE when power (ROM) is removed from the computer. LOBMYS LOBMYS LOBMYS 0 1 2 3 4 5 A B C D E ! “ # American Standard Code for Information Interchange (ASCII) – the most widely used coding system to represent data. Most personal computers and mid-range servers use ASCII coding scheme. 5 4/7/2012 RAM (Random
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