Topic 1 - What is an operating Flashcards
no
in this situation the application program will handle any data received from the core operating system functions and will be able to issue commands directly to the core operating system functions
note
remember application programs have the same access to the core operating system functions as the shell does
when a user is interacting with an application program is the shell still handling data
These programs sit alongside the shell and application programs and are installed at the same time as the operating system but are not technically part of the operating system itself.
they can facilitate in actions such as providing simple text editors or providing a means to configure and monitor the operating system.
describe what a
utility program
is
these comprise of:
- shell
- core operating system functions
- hardware
what are the 3
layers of an operating system
what is the role of a
shell
within an operating system
this performs the role of interpreting user input and passing the relevant command to the core operating system
note
this itself does not carry out any execution on hardware
what is another way to describe what the
shell
is
this could be described as an application program
for this stakeholder hardware independence / device independence means that:
they can create one version of there application for the targeted operating system instead of creating variants that take into account different types of hardware and having to implement low level code to interact with that hardware
for a
software developer
what benefit does hardware independence / device independence have
taking into account the
layers of the operating sytem
and the
user and kernel mode of the processor
describe how the
layered hierarchy of an operating
sytem will look
with these factors in place this now looks as follows
this:
- detects user input and passes it to the core operating system functions
- receives commands from the core operating system
describe in 2 points
hardware and the data it receives and sends
just like the shell application programs have the same access to this
except for the shell and the hardware what else can intercat directly with the
core operating system functions
this is ensured by allowing only the operating sytem to run in kernel mode
how is it ensured that only the operating system communicates with the hardware
this mode is used strictly by the operating system. Accessing key data structures and the hardware is only possible when running in this mode
describe the
kernel mode
of a processor
for this stakeholder hardware independence / device independence means that:
they can write one version of their software that interfaces with the operating system instead of writing variants that can interact with different types of software
for a
hardware developer
what benefit does hardware independence / device independence have
a user can interact with this either through a
- Graphical User Interface (GUI)
- Command Line Interface (CLI)
either interface may be chosen to carry out the same tasks although they both come with advantages and disadvantages
how does a user interact with a
shell
to be called this it would be able to:
- provide a user interface to load and run program
for example digital bathroom scales do not have an operating system installed and run only a single program, there is no interface that allows the loading or running of additional programs
- manage the storage of data and programs
the operating system can save your data to a drive whilst also providing various interfaces to do so such as the gui or command prompt
- support multitasking
operating systems can manage how hardware is used and in doing so can share the hardware resources between multiple running apps or services
- achieve device independence
the operating system allows for device independence meaning a variety of different hardware such as different keyboards can be used with a variety of application software with no compatibility problems
name 4 functions that could be used to
define what an operating system is
regarding the display and memory give an example for each of how the operating sytem shares these between multiple applications
Examples of resources being shared by the operating system are:
- Applications being provided their own window on the display so that the display can be shared by multiple applications
- Providing each application with their own exclusive space in memory that it can access and use via the operating system
for an
end user
what benefit does hardware independence / device independence have
for this stakeholder hardware independence / device independence means that
they do not need to worry about whether a new piece of hardware will work with there current software or vice versa
this is determined by stakeholders such as:
- end users
- software developers
- hardware / periphial developers
who essentially
determines the success of an operating system
this could be described as an application program
what is another way to describe what the
shell
is
where within the layers of the operating system do
application programs
reside
these sit on the top layer of the operating system with the shell
they have direct access to the core operating system functions just as the shell does
this
- passes data between the (shell and application programs) and the hardware
- executes commands on the hardware
- is made up of many subsystems, each able to carry out its specific task
in 3 points describe the
core operating system functions
for a
hardware developer
what benefit does hardware independence / device independence have
for this stakeholder hardware independence / device independence means that:
they can write one version of their software that interfaces with the operating system instead of writing variants that can interact with different types of software
in this situation this type of stakeholder would have interest in ease of use
in regards to the operating system what would an
end users
interest be
this mode is used by the shell, applications and any parts of the operating system that do not need direct access to the hardware
describe the
user mode
of a processor
this can run in:
- user mode
- kernel mode
what are the two modes that a processor can run in
yes
In principle it is possible to replace a shell with an alternative (either another graphical user interface or a command-line interface) that is still supported by the core functions of the operating system.
(open university)
in principle could you replace the shell with your own alternative
when a user is interacting with an application program is the shell still handling data
no
in this situation the application program will handle any data received from the core operating system functions and will be able to issue commands directly to the core operating system functions
note
remember application programs have the same access to the core operating system functions as the shell does
name 3 tasks the
shell
offers to the end user
this has the specific tasks of:
- providing the user with an interface to the operating system
- allowing the user to handle file management
- allowing the user to install and execute additional applicatio programs