Linux training in Chandigarh
Process Management and Scheduling
All modern operating systems are capable
of running many processes at the same
time - at least, this impression gets users.
If a system has only one processor, then
only one program can be run at the same
In the multiprocessor system, the number of processes running in parallel is determined by
the number of physical CPUs. Kernel and processors create turbulence of multitasking - the
capacity to function multiple operations in parallel by switching between periodic intervals
between various applications running on the system.
Since the switching intervals are very low, users do not see the intermediate short period of
inactivity and receive the impression that the computer is actually doing many things
simultaneously. This type of system management gives rise to many issues that solve
kernel, most of which are listed below.
❑ Applications should not interfere with each other unless it is explicitly
desired. For example, an error in Application A should not be promoted for
application B. Because Linux is a multipurpose system, it should also be
ensured that programs are not capable of reading or modifying the memory
content of other programs - otherwise , It would be extremely easy to
access other users' private data.
❑ CPU time should be shared between different applications as much as
possible, making some programs more important than others. I deal with
the first requirement - Memory Security - Chapter 3. In the current chapter,
I focus on the methods employed by the kernel so that the CPU can be
shared time and switch between processes.This double task is divided into
two parts which are performed independently of each other. Mauerer
runc02.tex V3 - 09/04/2008 4:15 pm Page 36 Chapter 2: Process
management and scheduling
❑ The kernel must decide how much time to devote to each
process and when to switch to the next process. It asks the
question of what exactly is the process actually next. Such
decisions are not platform-dependent.
❑When the kernel switches to process A to B, then it should be ensured that the B's
performance environment is exactly the same as the processor resources were finally
withdrawn. For example, the content of the processor registers and the structure of the
virtual address space should be the same. This latter work is highly dependent on the
It can not be implemented with C only, but assistance is required by the pure assembler
parts. The kernel subsystem, referred to as both task scheduler, is the responsibility of. CPU
time is allocated by the scheduler policy, which is completely different from the necessary
function switching mechanism to switch between processes.