Systems Software

Systems Software

1. O.S

   • Parts of an Operating System
     • The KERNEL
     • The DEVICE DRIVERS
     • The USER INTERFACE
     • The SYSTEM UTILITIES
   • The Kernel
     • The kernel has the task of: Loading / Unloading applications from memory Scheduling tasks to run efficiently on the CPU Memory management File storage to and from secondary storage devices such as the hard disk File management Data security
     • The kernel has the task of: Loading / Unloading applications from memory Scheduling tasks to run efficiently on the CPU Memory management File storage to and from secondary storage devices such as the hard disk File management Data security
   • User Interface
     • 1.Menu interface
     • 2.Command line interface
     • 3.Graphical user interface
   • Memory management
     • 1024 RAM HARD DISC
     • Programs have to be loaded into main memory (RAM) before they can run. And to run more than one program, they all have to be in memory at the same time.
     • It is essential that programs cannot interfere with one another - and so the memory manager gives each program a private memory area in which to run.
     • The memory manager is also responsible for moving programs between RAM and virtual memory, if that method being used.

2. Utility Softwhere

   • Utilities
     • Encryption software, Firewall, Anti-virus
     • Hard disk defragmentation, task manager monitor
     • data compression applications
   • Encryption utilities
     • Much of the data that we send via the internet is encrypted by software already built into the browser. Pages displaying "HTTPS" in their URL show that data can be sent safely and securely without having to take any additional measures.
     • But not all data is sent - some of it is just stored. Many organisations need to ensure that data they store is secure and cannot be accessed or viewed by unauthorised people. For example, under the Data Protection Act, all personal data about customers and staff must be stored in a secure manner.
     • An encryption utility can be used to secure data. The file is selected, a password created and the encryption utility encrypts the data within that file. In order to decrypt the data, the correct password must be entered before it will be unencrypted and presented to you in its original format.
   • Defragmentation utility
     • If a file is broken up ("fragmented") across too many separate memory sectors, it becomes difficult for the hard disk to access all of the pieces of a file in a timely manner. This can make the computer appear to be running slowly.
     • To prevent this, defragmentation utilities juggle the contents of memory sectors around to keep files together as much as possible. This ensures that the computer runs quickly and efficiently.
     • When a file needs to be stored, the operating system looks for free sectors on the disk. However, these sectors are rarely sequential (i.e. next to one another), instead they are usually scattered in different places across the hard disk.
   • Defragmentation
     • By rearranging the files so that they are stored sequentially the utility makes reading and writing of files to the hard disk, much faster and more efficient.
   • Compression utility
     • This is good because:- •less storage space is needed •it is faster to download and upload the file •better performance is achieved when streaming audio or video files
     • The MP3 file format uses lossy compression to make music and sound files smaller. It does this by discarding some sounds in the original data that you are not likely to hear such as very high / low pitch sound or its too quiet. There is a loss in quality but it is normally hardly noticeable and it does offer impressive compression - a 3 minute song stored as an MP3 file is about 4 Megabytes whilst the same song in uncompressed format is about 100 Megabytes.
     • Lossless compression does not remove any information from the file, instead it looks for patterns within the data that allows it to be stored more efficiently. Lossless compression is used for data files such as text documents. A very popular lossless compression method is the ZIP file format.
   • Backup utilities
     • It is essential that backups are performed regularly because it is all too easy to accidentally delete or overwrite files. Files can also be damaged by a computer virus, the hard disk could suddenly fail, or the computer could be damaged from a disaster like fire or flood.
     • The simplest way to backup data is to make a complete copy manually. Perhaps just by copy-pasting the full contents of Windows 'File Explorer' (or Linux equivalent). This copy can then be stored on a removable hard drive, a CD, a flash memory stick or in the Cloud. However, this method relies on you actually remembering to do this
   • Backup types
     • A complete or full backup copies all the data every time. This is not a problem for a small amount of data but if you are backing up a complete hard disk for example this could be many gigabytes and a very long time.
   • System Information and Diagnosis
     • When the information gathered by system information utilities indicates that there is a problem, diagnosis utilities will try to work out what that problem is, and either fix it directly or prompt the user with possible actions to take
     • System information utilities check the current status of the computer and attached devices. There are utilities that check the temperature of the CPU, how much memory is available, the speed of network connections, etc. System information utilities do not do anything with this information themselves, they only collect it.