What will happen when we invoke a system call and
say with an example of invoking a system call ?read? for a
device?
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Answer / dheeraj gahtori
Sysem call is an interface between process and the
operating system.
To See what happens when we invoke a system call we can
take an example.
If a system call is made to terminate the currently running
program , a dump of the memmory is taken somtime,
And a error message can be written if there is an error.
In this case the O.S. must transfer control to the command
interpreter. the command interpretor then reads the next
command.
And it depends upon the nature of the system wheather to
terminate or to continue........
We should also know that system calls are used for
process management, device management, Information
maintanance, communication etc....
| Is This Answer Correct ? | 7 Yes | 4 No |
Answer / kumar babu
• User process executes a syscall open a file.
• User process links to a c runtime library for open and
sets up the needed parameters in registers.
• A software trap is executed now and the operation switches
to the kernel mode.
- The kernel looks up the syscall vector to call "open"
- The kernel tables are modified to open the file.
- Return to the point of call with exit status.
• Return to the user process with value and status.
• The user process may resume now with modified status on
file or abort on error with exit status.
| Is This Answer Correct ? | 4 Yes | 1 No |
Answer / swamy
Qss. I would like to have some more interview questions
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| Is This Answer Correct ? | 1 Yes | 8 No |
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