The context switch is mainly the process that is followed by the CPU of the computer and that also follows to change from a single task and the process to some other while ensuring that tasks do not lead to any conflict. Effective switching of the context is critical when the computer provides the user-friendly as well as multitasking work.
In the CPU, the term “context” mainly refers to data in registers as well as program counter available at the specific moment in the time. The register also holds a current set of CPU instructions. The program counter that is even known as the register of instruction address is mainly the small amount of the quick memory that actually holds the address of the instruction that should get executed instantly after the recent one.
The context switch may also be well performed completely in the hardware or in the physical media. The Older CPUs, like those in a series of x86, do it in such a way. Though, many modern CPUs also perform the context switches through means of the software or the programming. The modern set of the CPU may actually perform various of the context switches each second. Hence, the user will also get the impression that the computer is even performing various different tasks in the parallel fashion, while CPU mainly alternates as well as rotates between the tasks at a quite high-speed rate.
On the other hand, context switch also occurs while the CPU switches from a single processor to the thread to various different processes or different thread.
Meanwhile, Context switching permits the CPU to simply handle various different processes as well as threads devoid of the need for some of the additional processors. Any of the operating system permits for multitasking depend on heavily using context switching that permits different processes to simply run at the same time. Moreover, there are 3 different situations where the context switch is important, as mentioned below.
– Multitasking – While CPU requires switching the processes completely in and out of the memory, so more than a single process may be simply running.
– User Switch / Kernel – While switching between the user mode and the kernel mode, it might also be used (though it isn’t usually important).
– Interrupts – While the CPU gets interrupted to return the entire data from the disk read.
The context switch (even at times it is referred to the process switch and the task switch) is switching of CPU which is also known as the central processing unit from a single process and thread to the other one.
The process (even at times referred to as the task) is also executing and running) instance related to the program. In the Linux, threads mainly are quite lightweight processes that may also run in parallel as well as share the address space (i.e., the complete array related to the memory locations) and different resources with the processes of the parent (i.e., processes which are created by them).
The context is the contents of the registers as well as a program of CPU counter at any specific point in time. The register is mainly a small amount of quite fast memory that is inside of the CPU (as it is opposed to slower RAM key memory that is outside of CPU) which is used for speed the execution related to the computer programs through offering the quick access to mainly use-values, usually those in midst of the calculation. The program counter is mainly the specialized register which truly indicates the position of CPU in their sequence of instruction and that also holds either address of instruction getting executed or address of next instruction that should be executed, according to a particular system.
Context switching may also be well described in more detail as kernel (i.e., core of operating system) that helps to perform the following mentioned activities with related to the processes (that includes threads) on CPU: (1) thereby suspending progression of the process as well as storing of the state of CPU’s (i.e., context) for the system that the process somewhere in the memory, (2) also retrieving context of subsequent process from the memory as well as restoring it in registers of CPU’s (3) returning to location that is well indicated by program counter (i.e., also returning to line of the code at where the process gets interrupted) to resume up the entire process.
The context switch is at times also well described as the execution of the kernel suspending of one process on CPU as well as resuming the execution of another process that had earlier been suspended. In spite of the fact that the wording may assist to clarify the entire concept, it may also be confusing because it is the process, through definition. Hence, wording suspending about the progression of the process may also be much preferable.
Mode Switches and Context Switches
The Context switches may simply occur just in the kernel mode. The mode of mode is the privileged mode related to CPU where only kernel runs and that also provides complete access to various locations of memory and all different system resources. Different programs include applications, that mainly operate in the user mode, but they may also run portions of kernel code through the system calls. The system call is mainly requested in the Unix-like set of the operating system through the active process (i.e., the process which is currently progressing in CPU) for all the services offered by the kernel, like input and the output or the creation of process creation which means creating of the new process.
On the other hand, the existence of the two modes in the Unix-like operating systems actually means that similar, though the simpler, operation is important when the system call for different causes for CPU to shift towards the mode of the kernel. It is also referred to as the mode switch instead of the context switch, as it never changes the recent process.
Conclusion
Context switching is mainly a crucial feature for multitasking operating systems. This system is one where the multiple processes execute with a single CPU apparently simultaneously and devoid of interfering with one other.