1. BT 1005 Managing Information Lecture 2 Data Representation, Storage and Transmission

2. Contents Processing Evolution Data Representation Components Networks Summary

3. 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

4. Data Representation Binary language Bits Bytes ASCII code http://en.wikipedia.org/wiki/Ascii http://en.wikipedia.org/wiki/Ascii

5. Components CPU (Central Processing Unit) Primary Storage Secondary Storage Input Devices Output Devices Communications Devices

6. 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)

7. 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

8. 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

9. Input Devices Keyboard Pointing Devices –Mouse –Touch screen Source Data Automation –Voice Input –Digital Scanner (OCR) –Barcode reader –RFID

10. Communication Devices Multi-core Cable –Twisted-pair vs Coaxial Fibre Optic Cable Radio Link Laser Link Advantages and disadvantages to each

11. Output Devices Cathode Ray Tube Digital Screen Printer Voice Output

12. Computer Networks Distributed Processing vs. Centralised Processing Client / Server Computing

13. 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