1.2.1 Operating systems

Question 1

Operating System

Answer 1

“Collection of systems software that manages the computer. Usually supplied with the computer. Most common operating systems are Windows, Linux, Unix, MacOS, iOS.”

Question 2

Memory Management

Answer 2

“The process of organising the flexible use of the computer’s main memory.”

Question 3

Paging

Answer 3

“The organisation of memory into fixed-sized units, called pages. The immediate-access store is organised as a number of physical pages. The logical pages used by the SPU can be assigned by the memory management unit to any page in physical memory.”

Question 4

Segmentation

Answer 4

“The splitting of a large program unto a number of smaller programs or segments. Each segment is a complete program that is executed separately. The function of the large program is achieved by running segments consecutively. Segmentation allows a large program to be executed on a computer with insufficient memory to store the whole program by carving up memory logically rather than physically.”

Question 5

Virtual Memory

Answer 5

“Used when sufficient immediate-access store is not available. Part of a disk drive is allocated to be used as if it were main memory. This is very slow, and the software will attempt to use the immediate-access store if possible.”

Question 6

Interrupt

Answer 6

41. 1.2.1c Operating systems Interrupt “A signal generated by a source such as an input or output device or a systems software routine that causes a break in the execution of the current routine. Control passes to another routine in such a way that the original routine can be resumed after the interrupt.”

Question 7

ISR

Answer 7

Interrupt Service Routine: “A software routine that hardware invokes in response to an interrupt. ISRs examine an interrupt and determine how to handle it.”

Question 8

Scheduling

Answer 8

“The method by which central processor time is allocated in a multi-access system.”

Question 9

RR

Answer 9

Round Robin: “A scheduling algorithm that deals with each user or task to be processed in turn.”

Question 10

FCFS

Answer 10

“A scheduling algorithm that deals with each user or task in the order in which they arrive, this can be thought of as a queue.”

Question 11

MLFQ

Answer 11

Multi-Level Feedback Queue: “A complex scheduling algorithm that deals with tasks based on a set of priorities and rules across different league tables, jobs in a certain table get promoted up or down their table based on these rules and can then end up in totally different tables if they relegated.”

Question 12

SJF

Answer 12

Shortest Job First: “A scheduling algorithm that deals with each user or task based on the getting the smaller ones out of the way.”

Question 13

SRT

Answer 13

Shortest Remaining Time: “A scheduling algorithm that deals with each user or task based on a calculating an estimated time remaking to complete.”

Question 14

Distributed OS

Answer 14

“An operating system where the software is spread over a collection of independent, networked, communicating, and physically separate nodes.”

Question 15

Embedded OS

Answer 15

“A highly specialised, often quite limited and cut down operating system design to fit inside a certain type of machine. For example computers in cards, tragic lights, cash machines, POS, elevators, drinks machines etc. In contrast to an operating system for a general-purpose computer, an embedded OS is typically quite limited, often running a single application. However, that single application is crucial to the device’s operation.”

Question 16

Multi-tasking OS

Answer 16

“Any type of system that is capable of running or appearing to run more than one program at a time.”

Question 17

Multi-user OS

Answer 17

“Any operating system designed to allow multiple users to log in and connect to it from different locations / machines at the same time. Specially designed for the sharing of resources such as files, programs or hardware (printers, scanners etc).”

Question 18

Real Time OS

Answer 18

“An operating system intended to serve real-time application process data as it comes in, typically without buffering delays.”

Question 19

BIOS

Answer 19

Basic Input / Output System: “Part of the operating system that handles the input and output of the computer. It enables the operating system to use the particular features of the hardware being used.”

Question 20

Device Drivers

Answer 20

“A computer program that operates or controls a particular type of device that is attached to a computer.”

Question 21

Virtual Machine

Answer 21

“An emulator of a particular computer system. Virtual machines operated based on the computer architecture and functions of a real or hypothetical computer, and their implementations may involve specialised hardware, software, or a combination of both.”

Question 22

Intermediate Code

Answer 22

“Half-way type of code which is standard across machine types. Runs on a virtual machine.”