1. Hardware and software Learning Objectives Learn the definition of hardware and software Learn that hardware is classified into internal and external components Learn that there are many difference types of software That many programs are created to make a computer system work, such as operating systems, library and utility programs Learn that specific software exists to convert programming code into machine code How the operating system manages resources

2. Hardware and software Starter How many external hardware components can you name How many internal hardware components can you name

3. Hardware and software Hardware Physical components of the computer Internal components Processing and storage devices External components Peripherals

4. Hardware and software Hardware External Components Mouse Keyboard Bar code reader Scanner Finger print scanner Retina Scanner Optical Mark Reader Optical Character Reader Magnetic Stripe Reader Smart Card Reader RFID Reader Touch Sensitive Screens Graphics Tables Voice Recognition Digital still camera VDU – CRT VDU – LCD VDU – Plasma Electronic Paper Impact Printer Inkjet Printer Laser Printer Plotter

5. Hardware Devices Mouse  Designed in 1964 by Douglas Engelbart  Use as a tool to aid use of Graphical user interfaces.  Uses a X-Y positioning system  Latest mouse uses wireless technology and more buttons for different functions.

6. Hardware Devices Keyboard  Enter text and numbers into a computer  Electronic circuits continually scan the keys to detect key presses  Converted to ASCII code or UNICODE for the computer to understand  Each key press sent as an interrupt to the CPU

7. Hardware Devices Bar code reader  Electronic Device for reading barcodes on various items  A sequence of black and white bars with coded information identifying the product.  Uses the change in light source to read the information.  Converted to ASCII by the scanner for a computer to understand.

8. Hardware Devices Scanner - Flatbed  Glass plane illuminated from beneath by a bright light  An array of light detecting sensors spanning the width of the glass pane is moved slowly up to pick up any light reflected from the course above.  Converted into an equivalent electric signal.  Colours scanner have three arrays – Red, Green, Blue  A digitised imaged is stored by the computer.

9. Hardware Devices Scanner – Fingerprint  A security device that takes a picture of your finger.  Sensor and decoder circuitry analyses the captured image and converts it into electric form for processing by a computer against stored fingerprint data.  Some are optical devices using light sensors – others use electrical currents to scan the finger.  Used on PCS to authenticate users.

10. Hardware Devices Scanner – Retina  Low energy infrared light source that is directed onto the retina  Photoelectric detectors convert the reflected light into an electrical signal to be processed by the computer.  Like the fingerprint the retina is unique for each person.

11. Hardware Devices Optical Mark Reader  Detects marks placed in predefined positions on a form  Passed under a light source  Intensity of reflected light from each row in the form is measured and converted by photoelectric sensors into an electrical equivalent.

12. Hardware Devices Optical Character reader  Uses an optical scanner  Scans in the text then analysis the digital images.  Used to automate postal sorting by recognising the postcode on the letters.  Some bills are created in a machine readable font.

13. Hardware Devices Magnetic Stripe Reader  Reads information encoded magnetically in a stripe on the back of a plastic card.  The particles on the magnetic strip is orientated in a way to encode binary data  Can store up to 2k of information

14. Hardware Devices Smart Card Reader  Reads from plastic cards that holds an integrated circuit chip  The Chip contains a microprocessor, a small amount of ROM, a small amount of EEPROM, a small amount of RAM and a computer bus system.  The chip is provided power when it is inserted into the reader.  Like a computer the mini applications are loaded into the RAM from the ROM and EEPROM and the microprocessor executed the applications.

15. Hardware Devices RFID Reader  Radio Frequency Identification  Uses radio frequencies to transmit data.  Receives data from a carrier without any physical contact.  Data capacity of RFID transponders is normally a few bytes to several Kb

16. Hardware Devices Touch Sensitive Screen  A VDU that allows user interaction with an application on the display.  Screen has been specially adapted so that the region just in front of the screen is criss-crossed by horizontal and vertical beams of infrared light. The breaking of these beams determines where on the application has been selected.  The coordinates of the broken beams is determined and sent back to the application.  The application maps these coordinates into an action.

17. Hardware Devices Graphics Tablet  Allows graphics to be drawn into the computer by hand like using a pencil.  Consists of a flat board and a stylus.  Pressing the board with the stylus operates a microswitch which is detected by the computer.  The boards contains electronics to detect the position of the stylus tip.

18. Hardware Devices Voice recognition  The computer can be trained to recognise a human voice and transforms speech into text using a microphone, sound card and appropriate software  This system can be used to issue commands to the computer and to dictate sentences directly into applications.

19. Hardware Devices Digital Still Camera  An electronic device used to capture and store photographs digitally on a memory cards before uploading to a computer via an USB Connection.  Can also record sound and video.

20. Hardware and software Hardware Internal Components Processor Hard disk Memory Chips Sound Cards Graphics Cards Mother Board

21. Hardware Devices Your Task – Specification Journal 17 (1.2) Create a research paper using the web with photographs of one hardware device of your choice. The sort of information you need to include is:  The history of the device  Where is it used  The capacity / Speed and other characteristics of the device.  The future development of the device  Practical real life examples of where it is used  Examples of models of the device and what all the technical details of that device means.

22. Hardware and software Software System Software Application Software

23. Hardware and software Software Application Software General-Purpose Application Software Special-Purpose Application Software Bespoke Application Software Examples: Word Processor Spreadsheet Database Management Web Browsing Examples: Payroll Web Browser Tax Calculator Examples: Air Traffic Control BBC TV licensing Service London Congestion Charging Scheme

24. Hardware and software Software System Software Operating Systems Library Programs Utility Programs Programming Language Translators Examples: Disk formatter File Compression Firewall Assembler Interpreter Compiler

25. Hardware and software Operating Systems Role of an Operating system  A system program  Manages the operation of the computer and application programs  Hides the complexities of the hardware from the user. (Virtual Machine)  Manage the Hardware resources to give orderly and controlled allocation of the processors, memories and input/output (I/O) devices among the various programs competing for them, and manage data storage.  Managing resources. Key ResourceOS Program ProcessorsProcessor Scheduling StorageMemory Management Input/Output DevicesI/O Management DataFile Management.

26. Hardware and software Operating Systems Process Scheduling – Resource Management Since computers are capable of running many programs, seemingly at the same time – It is the job of the operating system to make sure that each program is allocated enough memory and processor time to operate efficiently. This process of allocating these resources is called Scheduling.

27. Hardware and software Operating Systems TASK – Specification Journal 17 (1.3) Investigate the following scheduling algorithms and discuss their application and relative merits and drawbacks 1)FCFS Scheduling 2)SJF Scheduling 3)Priority Scheduling 4)Round Robin Scheduling 5)Multilevel Queue Scheduling

28. Hardware and software Operating Systems Resource Management (Cont) Operating systems also manages the input/output devices e.g. Allocating print jobs to printers Rendering the windows, frames and dialog boxes to the screen Controlling the read-write access to the hard disk. OPERATING SYSTEM DEVICE DRIVER DEVICE

29. Hardware and software Operating Systems Memory Management The operating system controls how the primary memory is used Stores details of all the unallocated locations in a section of memory known as the heap. When an application needs some memory – this is allocated from the heap. When the application has finished – the memory is deallocated and returned to the heap. Uses a memory map to identify what memory has been allocated to which task. Amount of memory used for each task depends on the application itself and the data it uses.

30. Hardware and software Operating Systems Memory Management APP1FILE1UNUSED APP1FILE1APP2FILE1UNUSED APP1FILE1APP2FILE1FILE2FILE1UNUSED APP1UNUSEDAPP2UNUSEDFILE2UNUSED APP1APP2FILE2UNUSED

31. Hardware and software Operating Systems Memory Management Virtual Memory If RAM is too small then some of the hard drive is used to act as RAM. Pages of memory are swapped back and fore causing a noticeable delay in the running of the application because the hard drive is slower than RAM. Alternative method is store only a core of the code of the application in the Kernel of the RAM and less commonly used tasks are only loaded when required. For instance – the commonly used editing tools of WORD and the less commonly used tools of the Spell Checker.

32. Hardware and software Operating Systems File Management Uses folders and directories to organise files.

33. Hardware and software Operating Systems File Management Some drives are partitioned to set the secondary storage into a more logical structure although in reality still on drive.

34. Hardware and software Tasks Answer the questions on Specification Journal 17 – 1.4 Hardware and software questions.