# ITCS 409-Operating Systems – Essaylink

## ITCS 409-Operating Systems

An operating system uses the Banker’s algorithm for deadlock avoidance when managing the
allocation of four resource types A, B, C and D to four processes P1, P2, P3 and P4. Resource
type A has 6 instances, B has 4 instances, type C has 3 instances and type D has 3 instances. The
table given below presents the current system state. Here, the allocation matrix shows the current
number of resources of each type allocated to each process and the Max matrix shows the
maximum number of resources of each type required by each process during its execution.

Available Allocation Max Processe
s

D C B A D C B A D C B A
1 1 1 1 1 1 1 1 2 1   2  2  P0
0 0 1 1 0 1 1 1 P1
1 1 0 3 1 1 1 4 P2
0 0 1 0 2 0 2 0 P3

Answer the following questions considering the above case study:

1. What will be the content of the Need matrix?
Need matrix can be found by subtracting max of processes from allocation of processes

Need matrix = max – allocation

Processes A B C D
P0 1 1 0 1
P1 0 0 1 0
P2 1 1 0 0
P3 0 1 0 2

1. Apply the Safety algorithm on the given case study and provide the results.
P0 is in Safe state
Available = 1 1 1 1
P0 [need] < available
P0 is executed
Finding the availability of P1
Available upon successful execution of P0 [available ] new = 1111 + 1111
= 2222
P1 [need ]< Available new
P1 will be executed
P1 executes successfully
Available[ new] = Available of P1 + Allocation of P1
2222 + 1100
33 22
NOW P2 will executed
Available[ new] = available of P1 + allocation P2
33 22 + 30 11
= 6333

Now P3 will be executed
Available [new ]= available of P2 + Allocation p3
6333 + 01 00
=6433
It is safely executed
Safe state sequence = P0 P1 P2 P3

1. Consider the following independent requests for additional resources in the
current state:

To Examine the safe state of the system in case of serving REQ1 and REQ2, independently.
Max of P0 = Max A + REQ P0
2 2 1 2 + 1 0 1 0
= 3 2 2 2
Need P0 = max P0 – available
= 3 2 2 2 – 1 1 1 1
= 2 1 1 1
need > available
P0 is rejected
max P1 = max A + REQ P1
1 1 1 0 + 0 0 1 1
= 1 1 2 1
need of P1 = max P1 – allocation
= 1 1 2 1 – 1 1 1 1
= 0 0 1 0
REQ1: P0 requests 1 units of A, 0 units of B, 1 units of C and 0 units of D
REQ2: P1 requests 0 units of A, 0 units of B, 1 units of C and 1 units of D

P1 is in safe state

1. Draw the resource- allocation graph for the given system.

Collaboration and assignment rules
The work must be all your own. Do not copy any parts of any of the assignments from anyone.
Do not make any parts of your assignments available to anyone, and make sure none can read
your files. The university policies on academic integrity will be applied rigorously. The Turnitin
system will be used to check the similarity of the assignment and the acceptable similarity is
15% ONLY. The total mark of this assignment is 20% of the total course work. Upload your
assignment to the Moodle system of Ahlia University before the indicated deadline date.
Assessment Rubric:
Assessment ILOs Mark

Q1 B1 4
Q2 B1 4
Q3 B1 4
Q4 B2 4
Discussion & presentation D1 2
Handing over the assignment on
Time

D3 2

Total: 20 marks

The post ITCS 409-Operating Systems first appeared on Krita Infomatics.

## Reviews, comments, and love from our customers and community

### Article Writing

Great service so far. Keep doing what you do, I am really impressed by the work done.

Researcher

### PowerPoint Presentation

I am speechless…WoW! Thank you so much! Definitely, the writer is talented person. She provided me with an essay a day early before the due date!

#### Stacy V.

Part-time student

### Dissertation & Thesis

This was a very well-written paper. Great work fast. I was in pretty desperate need for help to finish this paper before the due date, which was in nine hours.

Student

### Annotated Bibliography

I love working with this company. You always go above and beyond and exceed my expectations every time. Kate did a WONDERFUL job. I would highly recommend her.

Student

### Book Report / Review

I received my order wayyyyyyy sooner than I expected. Couldn’t ask for more. Very good at communicating & fast at replying. And change & corrections she put in the effort to go back and change it!

Student

### Essay (Any Type)

On time, perfect paper. All concerns & matters I had Tom was able to answer them! I will definitely provide him with more orders!

Student

### Case Study

Awesome! Great papers, and early! Thank you so much once again! Definitely recommend to trust James with your assignments! He won’t disappoint!

#### Kaylin Green

Student

Thank you Dr. Rebecca for editing my essays! She completed my task literally in 3 hours. For sure will work with her again, she is great and follows all instructions

Researcher

### Critical Thinking / Review

Extremely thorough summary, understanding and examples found for social science readings, with edits made as needed and on time. It’s like having a tutoring service available (:

Customer

### Coursework

Perfect!I only paid about \$80, which i think was a good price considering what my paper entailed. My paper was done early and it was well written!

Student