Systems software and security

Operating system software
1. Some operating systems
  1. Android OS Versions have nicknames such as Jelly Bean and Kit Kat OS X (Apple MACs) Versions have nicknames such as “Mountain Lion” and “Snow Leopard” iOS (iPhone/iPad) MS-DOS and Windows Google Chrome OS (based on Linux) Linux
2. Functions of an operating system
  1. Provides a user interface
  2. Manages
    1. memory --- multitasking --- peripherals --- files --- user access rights
3. User Interface
  1. Without a user interface we would have to communicate in binary! The user interface for a device has to suit how it is used....
4. Types of User Interface
  1. GUI: Graphical User Interface
  2. WIMP: Windows, Icons, Menus and Pointers
    1. User can click on icons using a pointer or cursor Icons representing functions mean less need to type instructions – just click on an icon or menu item Right-clicking brings up context-sensitive menus Different shaped pointers have different uses
  3. Menu-driven interface
  4. CLI: Command Line Interface
    1. All user commands must be typed in as text No graphics Quicker for expert users who know the commands Takes less space on the disk and in RAM
  5. Voice activated
  6. Real-time
5. To run a program, the computer must copy the program from storage into main memory
  1. The operating system keeps a record of where each program and its data are located It must not overwrite existing programs
6. Multi-tasking
  1. There are many background processes running on the computer as well
    1. They are taking it in turns to get processor time to execute instructions The OS must manage how the processes share the processor
Utility software
1. encryption software
  1. Encryption software is used to transform text so that it cannot be read without knowing the key to decode it
  2. Encryption tools : Uses
    1. Encrypt files and folders on a portable disk such as a USB memory stick
    2. Encrypt web communication
    3. Encrypt data on an organisation’s database
2. defragmentation software
  1. Disk defragmentation
    1. When you save a large file it may not fit on the disk in consecutive memory locations
    2. The file is referred to as “fragmented” Retrieving data from the file takes more processing More processing means reduced performance
      1. Defragmenting the hard disk reorganises files so they are stored together Processing time reduces so performance is improved Free space is also in one place so new files do not have to be fragmented
3. data compression software
  1. Utilities such as WinZip enables users to compress and decompress files or folders
    1. Reduces bandwidth usage and data consumption to download and send a compressed file Can enable file sizes to fit with strict email attachment or ISP limits Increases the amount of data that can be stored or archived on disk
4. What are utilities?
  1. The operating system controls and manages the computer system
  2. Utilities provide extra functionality that make it easier to use
  3. They can be packaged as part of the operating system or bought as stand-alone software programs
5. File management and transfer
  1. Think of the tools we use for managing our files We can move, copy and delete folders and files
6. Backup utilities
  1. You need to back up data on your hard disk – why?
    1. Windows has a Backup and Restore utility which will create a backup of your files on a regular schedule
      1. You need to save the backed up data onto an external hard drive
        Organisations from the smallest companies to the largest banks, cannot afford to lose any data
        Commercial backup utilities make sure that even in the event of fire or flood, all data can be recovered
  2. Backup and recovery
    1. Backing up files is vital to protect against loss from accidental or malicious damage, corruption or natural disaster
      1. Companies and individuals should adopt a routine backup strategy to insure against any losses
        Backup methods
        Full backup
        Complete backup of everything which can be restored independently of any other backup Takes greater time and disk space to create the backup
        Incremental backup
        Records only the changes made since the last backup A entire chain of backups is required to fully restore files
Network threats
Identifying and preventing vulnerabilities

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Systems software and security

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	Erstellt von Sam Houghton vor mehr als 7 Jahre