CPU and I/O Burst Cycles
Summary
TLDRThis lecture delves into the concept of CPU scheduling, focusing on the alternating cycles of CPU and I/O bursts within process execution. It explains CPU burst as the active use of the CPU by a process and I/O burst as the waiting period for input/output operations to complete. The lecture uses a diagram to illustrate these bursts and emphasizes the importance of understanding these cycles for effective CPU scheduling, aiming to maximize CPU utilization and minimize idle time.
Takeaways
- 🕒 CPU Scheduling is about assigning time slots to different processes for their utilization of the CPU to avoid idleness.
- 🔄 Process execution alternates between two main states: CPU execution state and I/O waiting state.
- 💡 A CPU burst is the period when a process is actively using the CPU for execution.
- 🔄 An I/O burst is the period when a process is waiting for an I/O operation to complete, not utilizing the CPU.
- 🔁 The execution of a process typically follows a cycle of CPU burst followed by an I/O burst, repeating until termination.
- 📈 Maximizing CPU utilization is a key goal of effective CPU scheduling by managing these bursts.
- 🚫 The CPU should not remain idle while a process is waiting for I/O operations; it should be assigned to other processes.
- 🔚 The final CPU burst ends with a system request to terminate the process's execution.
- 📊 The script provides an example illustrating the alternating sequence of CPU and I/O bursts during process execution.
- 📝 Understanding the concepts of CPU burst and I/O burst is crucial for grasping the fundamentals of CPU scheduling.
- 👋 The lecture concludes with an emphasis on the importance of these concepts for anyone studying CPU scheduling.
Q & A
What is the primary purpose of CPU scheduling?
-The primary purpose of CPU scheduling is to assign time to different processes for their utilization of the CPU, ensuring the CPU does not remain idle and maximizing its utilization.
What are the two main states a process can be in during its execution?
-The two main states a process can be in during its execution are the CPU execution state and the input/output waiting state.
What is a CPU burst?
-A CPU burst is the period of time when a process is actively using the CPU for its execution.
What is an I/O burst?
-An I/O burst is the period of time when a process is waiting for an input/output operation to be completed, and is not using the CPU.
Why is it important for a process to alternate between CPU burst and I/O burst states?
-It is important for a process to alternate between CPU burst and I/O burst states to ensure efficient use of the CPU, preventing it from being idle while waiting for I/O operations to complete.
What happens during the final CPU burst in a process's execution?
-During the final CPU burst, the system issues a request to terminate the execution of the process, which leads to the process being terminated once the burst is completed.
Can you provide an example of a CPU burst from the script?
-An example of a CPU burst from the script is when a process is performing operations such as load, store, add, and store, which require the use of the CPU.
Can you provide an example of an I/O burst from the script?
-An example of an I/O burst from the script is when a process is waiting for an input/output operation to be completed, such as reading from a file.
What is the significance of understanding CPU and I/O bursts in CPU scheduling?
-Understanding CPU and I/O bursts is significant in CPU scheduling as it helps in developing efficient scheduling algorithms that can balance CPU usage and I/O wait times, improving overall system performance.
How does the pattern of alternating CPU burst and I/O burst affect the performance of a system?
-The pattern of alternating CPU burst and I/O burst affects system performance by determining how efficiently the CPU is used. Efficient alternation can lead to higher CPU utilization and reduced idle times, enhancing overall system throughput.
What is the role of process cancellation in the context of CPU and I/O bursts?
-Process cancellation plays a role in CPU and I/O bursts by providing a mechanism to terminate a process's execution when necessary, allowing the CPU to be freed up for other processes, especially during the final CPU burst of a process's lifecycle.
Outlines
💻 CPU Scheduling and Burst Cycles Overview
This paragraph introduces the concept of CPU scheduling and the importance of utilizing the CPU efficiently to prevent idleness, especially during I/O operations. It explains the two primary states a process can be in: CPU execution state and I/O waiting state. The paragraph also defines CPU burst as the period a process actively uses the CPU and I/O burst as the time the process waits for I/O operations to complete. The explanation emphasizes the alternating pattern of these bursts in a process's execution, highlighting the goal of maximizing CPU utilization.
🔁 Example of CPU and I/O Burst Cycles in Process Execution
The second paragraph provides an illustrative example to demonstrate the cycle of CPU and I/O bursts in a process's execution. It describes a sequence of operations such as load, store, add, and file read/write, which require CPU usage (CPU burst) and periods of waiting for I/O operations to complete (I/O burst). The paragraph uses a diagram to visually represent this alternating sequence, showing how a process moves between needing CPU resources and waiting for I/O. It concludes with the final CPU burst, which includes a system request to terminate the process, marking the end of the CPU and I/O burst cycle for that process.
Mindmap
Keywords
💡CPU Scheduling
💡CPU Burst
💡I/O Burst
💡Process Execution
💡CPU Execution State
💡Input/Output Waiting State
💡Process Termination
💡Process Cancellation
💡Maximizing CPU Utilization
💡I/O Operations
Highlights
Introduction to CPU scheduling and its importance for maximizing CPU utilization.
Definition of scheduling as the assignment of time for different processes to use the CPU.
Explanation of the need to avoid CPU idleness during IO operations by assigning CPU time to other processes.
Introduction to the concepts of CPU burst and IO burst as key terms in CPU scheduling.
Description of process execution as alternating between CPU execution and IO waiting states.
Clarification of CPU burst as the time a process is utilizing the CPU for execution.
Definition of IO burst as the time a process is waiting for IO operations to complete.
Illustration of how processes alternate between CPU bursts and IO bursts during execution.
Explanation of the final CPU burst ending with a system request to terminate process execution.
Discussion on process cancellation and termination in the context of CPU and IO bursts.
Presentation of a diagram depicting the alternating sequence of CPU and IO bursts.
Example of process execution cycle with operations like load, store, add, and read from file.
Demonstration of how a process uses CPU during operations and waits during IO bursts.
Continuation of the pattern of CPU bursts followed by IO bursts until process termination.
Final emphasis on the importance of understanding CPU burst and IO burst in CPU scheduling.
Conclusion and appreciation for the audience's attention to the lecture on CPU and IO bursts.
Transcripts
in the previous lecture we have started
studying about CPU scheduling and we
have seen a basic introduction to CPU
scheduling now moving ahead in this
lecture we'll be studying about CPU and
i/o burst cycles now when we studied
about CPU scheduling in the previous
lecture we understood what the
scheduling is in a very basic term so
what we actually mean by scheduling is
the time that we are assigning to
different processes for their
utilization of the CPU so we don't want
the CPU to remain idle when one process
that was in hold of the CPU is waiting
for some IO operations to complete so
during that waiting time we want the CPU
to be assigned to some other process so
that the CPU doesn't remain idle and
hence we can maximize the utilization of
our CPU so with regards to that these
are two important terms that we should
know and we should understand CPU burst
and IO burst so we will try to
understand what we mean by CPU burst and
i/o bus and we will also understand what
is the CPU and IO burst cycle so process
execution consists of a cycle of CPU
execution and i/o we so when we studied
about CPU scheduling we already saw that
a process can be in either of these two
states and what are those states CPU
execution state and input and output
waiting state so processes alternate
between these two states now what do we
mean by these two states of CPU
execution and input/output wait so when
a process has begun its execution it is
under the CPU execution state that means
it is making use of the CPU for its
execution so if it is in that state we
call it a CPU execution state and after
that the process may need to wait for an
input/output operation to be complete in
order to continue with its execution at
that time when it is waiting for an
input/output operation to be complete we
say that the process is in IO wait State
so these are the two states in which a
process can be in once it has begun its
execution so processes always alternate
between these two states of
execution order input/output we so when
we use the term CPU burst we should
understand that what we mean by CPU
burst is the time when the process is
under CPU execution so when the process
is under CPU execution we say that that
is a CPU burst and then when the process
is waiting for some IO operation to be
complete or when it is waiting then we
call it IO burst so in simple terms CPU
burst and IO burst are nothing but the
time in which the process is under CPU
execution and IO wait respectively so
that is what we mean by CPU and i/o bus
so when a process execution begins these
are the stages it goes through so
process execution begins with a cpu
burst that is followed by an i/o burst
which is followed by another CPU burst
then another i/o burst and so on so we
see that when a process begins its
execution it starts with a CPU burst
that means it is under CPU execution it
is using the CPU for its execution and
at some point of time it will need some
input/output operations to be done so at
that time it will wait for the input or
output operation to be complete and that
is what we call IO burst
so there is an IO burst over here and
after the IO burst is complete that
means after the wait for the
input/output operation is complete it
will again use the CPU for its execution
so hence we have a CPU burst again and
then again it may need to wait for some
input/output operations and hence we
have a input/output burst and so on this
pattern will continue it will alternate
between these two states of CPU burst
and IO burst and it will go on so these
are the stages data process goes through
in its execution it is alternating
between the two states of CPU burst and
i/o burst so remember the meanings of
Scipio bus and i/o bus again
CPU burst is when the process is being
executed in the CPU and IO burst is when
the CPU is waiting for I
for further execution that means when
the CPU is waiting for some input/output
operations to be complete then we call
it IO burst so that is CPU burst an IO
burst and processes they alternate
between these two states during the
course of its execution and eventually
the final CPU burst ends with a system
request to terminate execution so once
these pattern continues and at the end
what happens is that there will be a
final CPU burst that means a final
execution of the CPU in which there will
be a system request to terminate the
execution of a process so we have
already studied abroad process
cancellation and we have seen what do we
mean by process cancellation and how
process termination takes place now let
us look at a simple example to see and
understand the way CPU burst and i/o
burst occurs in a process execution
cycle so here is a small diagram in
which the alternating sequence of CPU
and i/o bursts are depicted here we
assume that a process has begun its
execution and these are some of the
operations that are performed during the
execution of a process so here we see
there are some operations like load
store add store and read from file so
these are the operations that has to be
performed in the CPU so the process
requires the processor or the CPU for
this to happen at this time the process
is using the CPU and that time is known
as CPU burst and after this operation is
complete the process is waiting for some
input output operation to be performed
so here it is waiting for input output
and at that time when it is waiting for
input/output it is not using the CPU and
at that time we call it is a IO burst or
input/output burst and again we see that
after the wait was complete Alfred I Oh
operation has been completed
there are some other operations like
store increment index or a right to file
so these are operations that again
requires the CPU or the processor so at
this time when the process is doing this
with the help of the CPU we call it a
CPU burst
and again similarly it comes down and
has to use some input/output operations
so it is waiting for the input/output
operation to be complete and there we
have our yoke blessed again and moving
forward again there are some operations
like Lord store ad store it from file
which is similar to this one so we
already saw that this is our kind of
operation that requires the CPU so this
is again a CPU burst and then it is
again waiting for some i/o operation to
be complete which is known as the i/o
burst and this pattern continues and
until when will it continue it will
continue till the processes terminated
so when the process is going to be
terminated there will be a final CPU
burst in which the system will request
for the termination of the process and
once that is completed this process will
be terminated and then the CPU and IO
burst cycle for that particular process
will be finished that is what we mean by
CPU burst and IO burst and here we have
seen an example of how it happens so as
we continue studying about CPU
scheduling these are two important
things that we should always keep in
mind and whenever we use this terms of
CPU burst or i/o burst you should always
remember what it means as we have
studied in this lecture so I hope this
lecture about CPU burst and i/o burst
and CPU and i/o bus cycles were clear to
you thank you for watching and see you
in the next one
[Applause]
you
[Music]
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