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BT 1005 Managing Information. Lecture 2 Data Representation, Storage and Transmission. Contents. Processing Evolution Data Representation Components Networks Summary. Processing Evolution. Vacuum Tube – 5,000/100,000 cps Transistors – 250,000 cps Integrated Circuits
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BT 1005Managing Information Lecture 2 Data Representation, Storage and Transmission
Contents • Processing Evolution • Data Representation • Components • Networks • Summary
Processing Evolution • Vacuum Tube – 5,000/100,000 cps • Transistors – 250,000 cps • Integrated Circuits • Silicon Chips – 3/5 million cps • Digital Circuits • Still (basically) switches
Data Representation • Binary language • Bits • Bytes • ASCII code http://en.wikipedia.org/wiki/Ascii
Components • CPU (Central Processing Unit) • Primary Storage • Secondary Storage • Input Devices • Output Devices • Communications Devices
CPU • The Control Unit • The Arithmetic Logic Unit • Register Storage Area • Processing power (clock speed) • GHz • Gigahertz: a thousand million (billion) cycles per second • Until recently measured in megahertz (MHz)
Primary Storage • RAM (Random Access Memory) • Volatile • ROM (Read Only Memory) • Permanent • OS for example • Physically close to CPU • Working area for data and instructions
Secondary Storage • Hard Drives (Measured in Gigabytes/Petabytes) • A gigabyte equals about 2.3 million pages of text • about the length of your final year dissertation! • Magnetic Disk • Optical Disk • CD (-R and RW) – 700Mb • DVD (-/+R and RW) – 4.5Gb • HD and Blu-ray (Blue laser technology) – x3 capacity • Magnetic Tape • Flash Drives/Cards
Input Devices • Keyboard • Pointing Devices • Mouse • Touch screen • Source Data Automation • Voice Input • Digital Scanner (OCR) • Barcode reader • RFID
Communication Devices • Multi-core Cable • Twisted-pair vs Coaxial • Fibre Optic Cable • Radio Link • Laser Link • Advantages and disadvantages to each
Output Devices • Cathode Ray Tube • Digital Screen • Printer • Voice Output
Computer Networks • Distributed Processing vs. Centralised Processing • Client / Server Computing
Summary • The format of data has evolved with each technology but remains basically the same • Various methods exist to input, transmit and present output • Telecommunications technologies allow for networks to span continents