• Manages peripherals such as input and output devices
  e.g. Communicates with and sends data output to a printer / monitor / other valid output device
  e.g. also communicates with and receives data input to a keyboard / mouse / other valid input device

• Manages security

  • • Allows creation and deletion of user accounts

    • Allows users to logon and change passwords

    • Allows users to have different permissions when using the OS

• The O/S manages memory (RAM) 

  • • by ensuring all programs and data including itself is stored in correct memory locations/do not try to occupy the same memory location and therefore ensuring programs/data do not corrupt each other. 

    • The O/S manages memory (RAM) by ensuring all programs and data have enough memory allocated

    • The O/S can utilise virtual memory when not enough memory (RAM) is available to run a program 

• Manages network communication e.g. Spooling

  • In spooling, data is stored on hard disk / in memory / stored in a queue / in a buffer.  

  • A document is printed when printer is free / in correct order.  

  • A benefit of spooling is the user can carry on working / log off when waiting for job to print.

Example - Spooling is carried out on a computer when a user wants to print several documents by storing the documents in a queue and then the documents are printed when printer is free this has the benefit of allowing the user to carry on working or even log off when waiting for documents to print.

• Ensures different processes can utilise the CPU and do not interfere with each other or crash

• On a multi-tasking O/S, the O/S ensures that all tasks appear to run simultaneously

• Manages backing store by ensuring that data is stored and can be retrieved correctly from any disk drive

• Helps to organise files in a hierarchical directory structure

• Offers compression which can be used to save disk space

• O/S creates and maintains a filing system such as FAT or NTFS

  • • A file allocation table (FAT) is a file system developed for hard drives that originally used 12 or 16 bits for each cluster entry into the file allocation table. It is used by the operating system (OS) to manage files on hard drives and other computer systems. It is often also found on in flash memory, digital cameras and portable devices. It is used to store file information and extend the life of a hard drive. Most hard drives require a process known as seeking; this is the actual physical searching and positioning of the read/write head of the drive. The FAT file system was designed to reduce the amount of seeking and thus minimize the wear and tear on the hard disc.

    • NTFS is the most modern file system, which is also sometimes called the New Technology File System, is a process that the Windows NT operating system uses for storing, organizing, and finding files on a hard disk efficiently. . Windows uses NTFS for its system drive and, by default, for most non-removable drives. FAT32 is an older file system that's not as efficient as NTFS and doesn't support as big a feature set, but does offer greater compatibility with other operating systems. NT file system (NTFS), is a process that the Windows NT operating system uses for storing, organizing, and finding files on a hard disk efficiently. 

Manages Utility Programs e.g. Disc de-fragmentation - This is where related fragmented files are split up and stored on different parts of the disc.  The effect of disc fragmentation is that it will slow down disc access speed.  Disc de-fragmentation is when file parts are physically re-arranged (re-organised, moved, re-ordered) on disc (into the order required for access).  This allows the read heads to locate and load the file faster.

• • •  O/S offers file compression which is where the amount of data is reduced and the file is made smaller.  Compression is used to save disc space

    • Compression Method Example - Replace frequently occurring character combinations by a single character, for example replace ‘th’ with the digit 0.  One reason for compressing a file is to save storage space / upload to a web site / speed up transfer over a network / send as email attachment