systems solftware Flashcards
os
An operating system (OS) is software that controls the computer’s hardware and software resources. It allows applications to interact with the hardware on a computer.
did early comp have os
no
what do os do
they manage:
Processor management
Inputs, outputs, and interrupts
Memory management
Security
when you open a program what does os do
finding the appropriate data from the secondary storage and loads it into the main memory.
what does os instruct after loading data to sec strg
The Processor is then instructed to execute the processes needed to open that program.
scheduler
OS uses this to swap tasks in and out of the processor so that it appears to the user that the computer is carrying out more than one task at the same time.
This is known as multi-tasking
how to incrresse efficientcy multitasking
incrs num of cores
The instructions and data needed for a process have to be available in main memory. To ensure this, the OS runs?
a memory manager program, which:
Keeps track of what portions of memory have been allocated
Maps memory to each process
Determines how much memory to allocate to each process
Determines when a portion of memory should be available for a process
user interface tools used for file management
Creating
Renaming
Moving
Deleting
data - what does os control
the operating system controls how data is stored and retrieved.
The operating system keeps track of where the files are stored on the secondary storage device so that they can be quickly accessed when requested.
backing storage management
Backing storage refers to any Non-volatile memory storage device. The operating system keeps a directory of where files and programs are stored so that they can be accessed quickly when they are requested and transferred into main memory.
pros keeping a directory
Keeping a directory also speeds up storage and saves computational resources, rather than having to search for free space every time a user wants to save a file.
quicker access times to files as well
key role of os
A key role of the operating system is controlling and using input and output (I/O) devices.
how os manage i/o device
The OS manages I/O devices in various ways:
It records which device requires processor time so that the processor can communicate with the device without any conflicts
It prioritises processes based on control signals that the I/O device sends and receives
what do devices use to allocate time to urgent things
to allocate time to processes that are deemed urgent, devices use interrupts
whats an interrupt
An interrupt is a signal that is sent to the processor to request immediate attention. When the processor receives this request, it suspends what it is doing and runs the process associated with the interrupt.
reasons for using interrupts
The processor can be interrupted for a number of reasons, including:
A hardware device has signalled that it has data to process
A hardware device has completed a task that it was asked to do
A software process needs a service to be provided or OS function to be performed
An allotted amount of time has expired and an action needs to be performed
A hardware failure has occurred and needs to be addressed
device driver
A device driver is a program that controls the operation of a specific type of device that is part of a computer system
wat do device drivers provide
a device driver provides an Interface that allows the operating system to interact with the device, which in turn allows it to interact with the software on your computer.
how r deice drivers installed?`
drivers are installed using software that is either built into the operating system, or where necessary, downloaded from the internet`
cons of generic device drivers
The generic device driver may be missing features that the specific device driver would provide
The operation of a generic device driver may be inefficient, meaning that the computer system’s performance would slow down
how does os support secuirty of device
by ensuring that the system resources are protected from unauthorised access.
os include security specific software like
Firewalls
Anti-malware
Checks for software updates
also can give access rights
CLI
A CLI allows the user to interact with the system by typing in specific commands in a command prompt.
There are no graphics or icons
