Title: Year 12 / Computer Science / Theory / 5 - System Software / 5.1 - Operating System
Tags: en

Q: Explain why a computer system requires an Operating
System
A: operating system is a set of programs designed to run in background of computer system which controls operation of computer system, provides a user interface, controls how computer responds to users requests, controls how hardware communicate, provides environment in which application software can be executed, os hardware is unusable without os, as os is interface and controls communication between user and hardware

Q: State 5 examples of key management tasks carried out by the operating system
A: main memory management, file management, security management, hardware management, processor management

Q: Explain how the operating system carries out main memory management
A: it uses memory protection to ensure 2 programs dont try to use same memory space, swaps data to and from hard drive, uses paging, uses virtual memory

Q: Explain how the operating system carries out file management
A: provides file naming conventions
maintains directory structure
allocates space to particular files

Q: Explain how the operating system carries out security management
A: provides and checks usernames and passwords
ensures data privacy
prevents unauthorised access
carries out automatic backup or system roll back

Q: Explain how the operating system carries out hardware management
A: installs drivers,
sends and receives data from buffer
sends commands to device,
controls access to data sent to and from peripherals,
receives and handles interrupts from hardware devices

Q: Explain how the operating system carries out processor management
A: manages scheduling of processes, allows multitasking, ensures fair access, handles priorities, allows processes to share information, provides resolution of conflicts when 2 or more processes require the same resource

Q: State examples of 6 typical utility software provided with an operating software
A: disk formatter, virus checker, defragmentation software, disk contents analysis/disk repair software, file compression, back up software

Q: Describe the need of disk formatter software
A: prepares a hard disk to allow data to be stored on it,
deletes existing data on disk,
partitions disk into logical drives, sets up specified file system, prepares disk for initial use, checks errors on disk

Q: Describe the need of virus checker software
A: checks for and then removes any viruses found,
constantly checks all incoming and outgoing files

Q: Describe the need of defragmentation software
A: reorganises disk contents, moves split files so theyre contiguous, creates larger area of contiguous free space

Q: Describe the need of disk contents analysis/disk repair software
A: checks for errors on disk and resolves them, retrieves files from damaged disks, reconstructs directory, marks bad sections on disk as unusable

Q: Describe the need of file compression software
A: reduces file size by compressing contents and removing redundant data in files
improves computers performance by reducing data that needs to be stored

Q: Describe the need of back up software
A: makes copy of files on another storage medium in the event of a hard drive failure, user error, disaster or accident, regular process, provides synchronization between devices

Q: Explain what program libraries are
A: pre written code that can be linked to a software in development without amendments,
can perform common or complex tasks,
takes form of classes, software in development often made using existing code from program libraries

Q: State the benefits of using program libraries
A: saves time as code is already written, smaller testing time as its already tested and will have been used by others, the library can be a complex algorithm which the user doesnt need to understand to use it, code should conform to industry standards, simplifies code

Q: Explain what Dynamic Link Library (DLL) files are
A: shared library file that contains code and data, saved separately from main exe file, code only loaded to main memory when required at run time, available to several applications at once, act as modules in complex programs

Q: Describe the drawbacks of library files
A: compatibility issues, might not work with other code, not guaranteed testing, may be unknown bugs, may give unexpected results

Q: Describe the drawbacks of Dynamic Link Library files
A: executable code not self contained so dll file needs to be included at run time, linking software has to be available at run time to link dll file, dll file not being present can cause errors