software and software development Flashcards
Define the term operating system?
An operating system is a collection of programs which work together to provide an interface between the user and computer.
Define paging?
Paging is a type of memory management where the memory is split up into equal sized sections known as pages.
These can be swapped between main memory and hard disk.
Define segmentation?
This is another type of memory management where memory is split up into logical sized divisions known as segments which vary in size. Segments can be allocated to blocks of code such as loops or if statements.
What is virtual memory?
VM uses a section of then hard drive to act as RAM when space in main memory is insufficient to store programs being used. Programs not currently in use are moved to VM via paging which frees up memory for other programs in RAM.
What is an interrupt (ISR)?
Signals generated by software to indicate to the processor that a process needs attention.
During the ISR the processor checks the contents of the interrupt register at the end of FDE. If a higher priority interrupt exists the current contents of the registers in the CPU are temporarily moved to a stack. Processor then responds to interrupt. Once complete the flag is reset and the contents of the stack are moved back into the registers to be executed only if another high priority interrupt doesn’t exist.
What is a distributed OS?
An OS which runs across multiple devices, allowing the load to be spread across multiple computer processors when a task is run.
What is an embedded OS?
Built to perform specific tasks, this OS is catered towards a specific device.
What is a multi tasking OS?
An OS which enables users to carry put tasks seemingly simultaneously. This is done via time slicing to switch quickly between programs in memory
What is a multi user OS?
multiple users make use of one computer typically a super computer within a multi user system. Therefore a scheduling algorithm must be implemented.
