Proccesses :-
A batch system executes jobs, whereas a time-shared system has user programs, or tasks. Process is a program in execution. A program is only one part of process ,the process also contains the execution state of program.
It also includes the current activity, as represented by the value of the program counter and the contents of the processor ‘s registers. a process generally includes the process stack, which contains temporary data (such as method parameters, return addresses, and local variables), and a data section, which contains global
variables.
So process,including--
a.)A program in execution
b.)An instance of a program running on a computer
c.)The entity that can be assigned to and executed on a processor
d.)A unit of activity characterized by the execution of a sequence of instructions, a current state, and an associated set of system resources
Each process provides the resources needed to execute a program.A single process might contains multiple threads. A process has a virtual address space, executable code, open handles to system objects, a security context, a unique process identifier.A process is always stored in the main memory also termed as the primary memory or random access memory.On a multiprocessor system, multiple processes can be executed in parallel.
At any given point in time, while the program is executing, this process can be uniquely characterized by a number of elements, including the following:--
• Identifier:- A unique identifier associated with this process, to distinguish it
from all other processes.
• State- If the process is currently executing, it is in the running state.
• Priority:- Priority level relative to other processes.
• Program counter: -The address of the next instruction in the program to be
executed.
• Memory pointers: -Includes pointers to the program code and data associated
with this process, plus any memory blocks shared with other processes.
• Context data: -These are data that are present in registers in the processor
while the process is executing.
• I/O status information: -Includes outstanding I/O requests, I/O devices (e.g., tape
drives) assigned to this process, a list of files in use by the process, and so on.
• Accounting information: -May include the amount of processor time and clock
time used, time limits, account numbers, and so on.
A batch system executes jobs, whereas a time-shared system has user programs, or tasks. Process is a program in execution. A program is only one part of process ,the process also contains the execution state of program.
It also includes the current activity, as represented by the value of the program counter and the contents of the processor ‘s registers. a process generally includes the process stack, which contains temporary data (such as method parameters, return addresses, and local variables), and a data section, which contains global
variables.
So process,including--
a.)A program in execution
b.)An instance of a program running on a computer
c.)The entity that can be assigned to and executed on a processor
d.)A unit of activity characterized by the execution of a sequence of instructions, a current state, and an associated set of system resources
Each process provides the resources needed to execute a program.A single process might contains multiple threads. A process has a virtual address space, executable code, open handles to system objects, a security context, a unique process identifier.A process is always stored in the main memory also termed as the primary memory or random access memory.On a multiprocessor system, multiple processes can be executed in parallel.
At any given point in time, while the program is executing, this process can be uniquely characterized by a number of elements, including the following:--
• Identifier:- A unique identifier associated with this process, to distinguish it
from all other processes.
• State- If the process is currently executing, it is in the running state.
• Priority:- Priority level relative to other processes.
• Program counter: -The address of the next instruction in the program to be
executed.
• Memory pointers: -Includes pointers to the program code and data associated
with this process, plus any memory blocks shared with other processes.
• Context data: -These are data that are present in registers in the processor
while the process is executing.
• I/O status information: -Includes outstanding I/O requests, I/O devices (e.g., tape
drives) assigned to this process, a list of files in use by the process, and so on.
• Accounting information: -May include the amount of processor time and clock
time used, time limits, account numbers, and so on.
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