Operating systems 2 Flashcards
Role of an operating system
The operating system on a digital device is the link between the hardware and the software. It passes messages back and forth and carries out instructions from the software to the hardware.
The operating system is what coordinates all the operations of your computer. It manages all the resources on the computer, such as the CPU and RAM, and controls the software and hardware. Without it, your PC would be useless.
Real time OS
(RTOS) Inputs are processed and responded to instantaneously.
Why choose real-time?
It provides fast response.
It is best used where inputs must be processed and responded to immediately, such as traffic light and air traffic control systems.
Single user single task
One user can perform only one single task at a time, and one application can run at a time.
Why choose single-user single task?
• It requires fewer resources.
• It is best used on devices that have limited processing and memory, which could not handle running multiple applications, for example basic mobile phones or
a simple handheld game (such as a Virtual Pet).
Single user multitasking
One user can use the system at a time, but many applications can run simultaneously,
Why choose single-user multitasking?
• It allows the user to use several applications at once.
• It is best used on systems where a user needs to be able to switch quickly between applications, for example an office worker using a laptop or desktop PC.
Multi user OS
Many users can use the system at the same time and can run many applications simultaneously.
Why choose multi-user?
• Processing and resources can be shared by multiple-users.
• It is best used where many users need access to the same processing or resources at the same time, for example web servers.
Role of an operating system
Networking
Security
Memory management
Device drivers
Multitasking
Networking
OS simplify networking in a computer. The operating system implements number of networking technologies such as: the TCP/IP stack
network utility programs such as trace route device drivers for the network interface card.
Security
A number of features built into a computer system to improve security
* user authentication
* antivirus and computer software
* backup facilities
Memory management
The operating system manages the computers resources to do this the os decides and tracks:
*Which processes to allocate memory to
*How much memory to allocate to each process
*When to unallocate memory
*Transferring data to free ram
Device drivers
An operating system comes with generic device
drivers that work with a wide variety of different
peripheral devices, allowing them to communicate
with your computer. However, most hardware
comes supplied with specific drivers to take full
advantage of the hardware’s capabilities.
Multitasking
Most operating systems allow you to run more
than one application simultaneously. To do this,
the operating system must be able to allocate
resources (CPU, memory, disk space) to each
application in order to allow it to complete two
or more tasks simultaneously.
