System Software

System Software

1. Utility System

   • Utility Software: File Compression, Disk Defragmentation, File Repair, Disk Copying, Disk Formatting, Disk Backup / Restore, Anti-Virus.
   • Utility software File Compression: Reducing the size of the file by performing an algorithm on the original data. Lossless: The original file can be re-created as no data is lost. Lossy: Some of the original data is lost and the original file can not be re-created
   • Utility software Disk Defragmentation: When a hard disk drive is new – files get added onto the disk in order – very much like starting with a blank piece of paper and adding to it As files are deleted – this leaves gaps When new files are saved – the files fill the gaps and become fragmented Defragmentation software groups fragmented files back together
   • Utility software Encryption: Encryption means to scramble data in a way that it is unreadable to anybody who doesn’t have a key to be able to unscramble this. Data is encrypted using a key and then decrypted using a key Data is encrypted so that it is unreadable if anyone is to intercept it .
   • Utility software Back-ups: Completed to ensure there is a way of restoring files/data/programs in case of computer failure Copies of data and/or software are taken regularly and usually stored in a different location Ensures that if computers are stolen or damaged in for e.g. a fire or a natural disaster that data can be restored and a company do not lose much money
   • Utility software Back-up types: Incremental= A full backup is made initially Each night only the files which have been changed since the last incremental back-up are copied Much faster to complete that full back-ups Takes much longer at restoring than a Full Back up as the full back up would need restoring first and then every incremental back-up since the last full back up
   • Utility software Back-up types: Full= A copy of all data and software on the hard disk drive / server is copied to a backup medium (e.g. an external hard disk drive / DVD-R) and the medium is kept at a different location Take a long time to complete (usually overnight) Recovery takes a long time as it restores all data and programs

2. Operating System

   • What is Software? An algorithm that is coded for a computer to use to perform tasks is a program. Programs are generally known as software, to distinguish them from the hardware on which they run. The term software also includes the associated data that a program needs. Software is written using programming languages, which is another type of software.
   • Software Categories: There are many types of software but they generally fall into two main categories: System software and Application software
   • System software: Systems software is a type of software that controls the computers hardware. It provides an interface between the user of the computer and the hardware. An Operating System is a type of Systems Software.
   • System software (operating system): An operating system, sometimes called a platform, is a collection of programs that control the hardware in a computer or device. At the heart of the operating system is the kernel. The kernel is a computer program that is the core of a computer's operating system, with complete control over everything in the system. On most systems, it is one of the first programs loaded on start-up.
   • System software (operating system): Examples of operating systems: Windows: UNIX: MacOS:
   • System software: The operating system is loaded from disk into RAM on the typical desktop or laptop computer. For devices running embedded systems the operating system is stored on ROM or in flash memory. Software stored in this way is called firmware. Larger computers also have firmware in ROM to take care of boot up.
   • System software (operating system): Examples of operating systems: LINUX is designed to behave like UNIX but was developed separately and is the basis for many other operating systems. The LINUX kernel has been adapted to run devices from supercomputers to mobile phones. Some LINUX based systems include: Red Hat Debian Ubuntu Google’s Android smart phone operating system
   • Operating system - Multi-tasking: Multi-tasking allows the computer to make best use of the CPU. The CPU works much faster than RAM and the other components of the computer. While the CPU waits for other actions to complete, e.g. loading data to RAM, it works on other tasks. Users often have several tasks running at the same time, for example word processor, email program, music player, spreadsheet and web-browser.
   • Operating system - Memory Management: When a program is running it must be in the computer’s main memory and the operating system must manage where in memory each program and the data it needs must go.
   • Operating system - Interface: For specialist users, e.g. network technicians, a GUI is less efficient. A GUI requires several stages to issue a command and has large processor overheads. All operating systems have a command line interface that allows the user to type in direct commands to access the operating system functions.
   • Operating system - Interface: User Interface The user interface is how the user interacts with the system. This can be provided as part of the operating system or can be a separate program running on top of the operating system. Windows® uses a graphical user interface (GUI) supplied as part of the operating system. A GUI uses icons (small pictures) to represent the resources and actions, reducing the need to learn commands. GUIs use mouse pointers or touch screens to select objects.