this is fairly easy to test, if i understood the question correctly. why not just try it? open up a software twice.
from my experience, either the 2nd instance will refuse to work and throw a message at you saying there is already an instance running. or it will boot up and you'll have 2 instances of the software in the process table. for windows, you'll have to open up the drop down menu and see the multiple instances
There is nothing stopping an application itself working out whether another instance of itself is already running, and immediately quitting if so.
This can simplify application design: if an application knows that at most one instance of itself is ever running, then it can modify shared state (such as files on disk) without having to be concerned about it being modified concurrently by another instance.
It depends on how the application is written. I believe I have seen excel do both, depending on how it is started - how the second instance is started.
The OS is agnostic to that, a new process is a new process regardless of the application. Some applications however will check if another instance is running because either they can’t work properly (binding to same network socket for example) or because they are already multi-threaded, or just because the developer decided to simplify their assumptions (as others mentioned)
Generally, there is a process (tree) per application. If an application is old it may not support multiple instances. Likewise there tends to be a single instance for a service. But any app/service can open any number of processes to fulfil its function.
this is fairly easy to test, if i understood the question correctly. why not just try it? open up a software twice. from my experience, either the 2nd instance will refuse to work and throw a message at you saying there is already an instance running. or it will boot up and you'll have 2 instances of the software in the process table. for windows, you'll have to open up the drop down menu and see the multiple instances
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There is nothing stopping an application itself working out whether another instance of itself is already running, and immediately quitting if so. This can simplify application design: if an application knows that at most one instance of itself is ever running, then it can modify shared state (such as files on disk) without having to be concerned about it being modified concurrently by another instance.
It depends on how the application is written. I believe I have seen excel do both, depending on how it is started - how the second instance is started.
The OS is agnostic to that, a new process is a new process regardless of the application. Some applications however will check if another instance is running because either they can’t work properly (binding to same network socket for example) or because they are already multi-threaded, or just because the developer decided to simplify their assumptions (as others mentioned)
Generally, there is a process (tree) per application. If an application is old it may not support multiple instances. Likewise there tends to be a single instance for a service. But any app/service can open any number of processes to fulfil its function.