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