Page 15 - Campus Chronicles Technical Magazine 2021

• the same behavior as FCFS. • Suitable for applications with fluctuating time and
• Average waiting time of the Round Robin algorithm resource requirements.
is often long. Disadvantages:
• Context switching is done a lot more times and • If the system eventually crashes, all low priority Cloud
adds to the more overhead time. processes get lost.
• If high priority processes take lots of CPU time,
Priority Scheduling: then the lower priority processes may starve and
In Priority scheduling, there is a priority number will be postponed for an indefinite time. Computing
assigned to each process. In some systems, the lower • This scheduling algorithm may leave some low
the number, the higher the priority. While, in the others, priority processes waiting indefinitely.
the higher the number, the higher will be the priority. • A process will be blocked when it is ready to run By Ms. B. Siva Naga Sai Saranya,
The Process with the higher priority among the but has to wait for the CPU because some other
available processes is given the CPU. There are two process is running currently. B. Tech (ECE)- 19UP1A0447
types of priority scheduling algorithm exists. Oneis • If a new higher priority process keeps on coming in
Preemptive priority scheduling while the other is Non the ready queue, then the process which is in the
Preemptive Priority scheduling.The priority number waiting state may need to wait for a long duration
assigned to each of the process may or may not vary. If of time.
the priority number doesn't change itself throughout
the process, it is called static priority, while if it keeps Multilevel Queue Scheduling: Cloud computing is a virtualization-based technology There are the following operations that we can do
changing itself at the regular intervals, it is called Multilevel queue scheduling is used when processes in that allows us to create, configure, and customize using cloud computing:
dynamic priority.In the Non Preemptive Priority the ready queue can be divided into different classes applications via an internet connection. The cloud • Developing new applications and services
scheduling, The Processes are scheduled according to where each class has its own scheduling needs. technology includes a development platform, hard • Storage, back up, and recovery of data
the priority number assigned to them. Once the For instance, foreground or interactive processes and disk, software application, and database. • Hosting blogs and websites
process gets scheduled, it will run till the completion. background or batch processes are commonly divided. • Delivery of software on demand
Generally, the lower the priority number, the higher is Foreground and background processes have different The term cloud refers to a network or the internet. It is a • Analysis of data
the priority of the process. The people might get time requirements and hence will have different technology that uses remote servers on the internet to • Streaming videos and audios
confused with the priority numbers, hence in the GATE, scheduling needs. In this case, multilevel queue store, manage, and access data online rather than local
there clearly mention which one is the highest priority scheduling will be used. For each class of processes, drives. The data can be anything such as files, images, Characteristics of Cloud Computing
and which one is the lowest one.In Preemptive Priority the ready queue is divided into separate queues. documents, audio, video, and more. The characteristics of cloud computing are given
Scheduling, at the time of arrival of a process in the For example, there are five processes: below:
ready queue, its Priority is compared with the priority of 1. System Processes, 2. Interactive Processes, Small as well as large IT companies, follow the
the other processes present in the ready queue as well 3. Interactive Editing Processes, 4. Batch Processes, traditional methods to provide the IT infrastructure. 1) Agility: The cloud works in a distributed computing
environment. It shares resources among users and
as with the one which is being executed by the CPU at 5. Student Process. That means for any IT company, we need a Server
that point of time. The One with the highest priority Room that is the basic need of IT companies. In that works very fast.
among all the available processes will be given the Every queue will have an absolute priority over low server room, there should be a database server, mail 2) High availability and reliability: The availability of
CPU next.The difference between preemptive priority priority queues. No process can run until the high server, networking, firewalls, routers, modem, servers is high and more reliable because the chances
scheduling and non preemptive priority scheduling is priority queues are empty. For the above example, until switches, QPS (Query Per Second means how much of infrastructure failure are minimum.
that, in the preemptive priority scheduling, the job and unless the queues for system processes, queries or load will be handled by the server), 3) High Scalability: Cloud offers "on-demand"
which is being executed can be stopped at the arrival of interactive processes, and interactive editing configurable system, high net speed, and the provisioning of resources on a large scale, without
a higher priority job.Once all the jobs get available in processes are all empty, no other process can run. maintenance engineers.
the ready queue, the algorithm will behave as non- having engineers for peak loads.
preemptive priority scheduling, which means the job Advantages: To establish such IT infrastructure, we need to spend 4) Multi-Sharing: With the help of cloud computing,
scheduled will run till the completion and no • Multilevel queue scheduling helps us apply lots of money. To overcome all these problems and to multiple users and applications can work
preemption will be done. different scheduling algorithms for different reduce the IT infrastructure cost, Cloud Computing moreefficiently with cost reductions by sharing
processes. common infrastructure.
comes into existence.
Advantages: • It will have a low scheduling overhead. 5) Device and Location Independence: Cloud
• Easy to use scheduling method Disadvantages: computing enables the users to access systems using a
• Processes are executed on the basis of priority so • There are chances of starving for the lower priority web browser regardless of their location or what
high priority does not need to wait for long which processes. device they use e.g. PC, mobile phone, etc. As
saves time • It is inflexible in nature. infrastructure is off-site (typically provided by a third-
• This method provides a good mechanism where
the relative important of each process may be Campus Campus party) and accessed via the Internet, users can connect
precisely defined. CHRONICLES 14 15 CHRONICLES from anywhere.
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