Computer Organisation and Architecture

Running head: COMPUTER ORGANISATION AND ARCHITECTURE
Computer Organisation and Architecture
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COMPUTER ORGANISATION AND ARCHITECTURE
Question 1:
CPU – Most of the modern-day CPU tends to perform multitasking operations with respect to
the fact that the users, as well as the tasks, are well played by this unit. Moreover, the CPU is
depicted to be shared amongst the various processes as well as the hardware timers that are
engaged to assure that there will be no single process which may monopolise the environment
of the CPU (Abdoos 2017). The OS selects which will be the next process that gets executed
by the processor and how much time it will be taken to complete the execution. This method
is known as process scheduling.
Main memory – It refers to the primary memory of the system. The main memory consists of
a vast storage system, which is directly accessed by the processor. A program starts execution
from the main memory (Abirami, Sridhar and Vaidhyanathan 2015). The potential operating
system tends to implement a vast range of the system flags. This will help the deadlock to be
prevented.
Storage devices – O.S. manages communication between devices through the use of various
drivers. It performs the functionalities for operating the device –
Monitor all devices. The I/O controller program is used to monitor all the devices. It decides
the next process, which gets the processor to execute the task and the time required by the
processes to accomplish the task. Perform de-allocation for the devices as well. The
significant unit of the storage potentially faces the situation of deadlock when the resources
of the different files are being accessed from the various resources (Gupta, Yadav and Goyal
2016). Thus to avoid the situation of deadlock, it may follow a simple process that it needs to
maintain the overall status of a particular device.

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COMPUTER ORGANISATION AND ARCHITECTURE
Files - The significant situation in the file system can also be identified to face a situation of
deadlock. The condition to prevent a deadlock will have adhered in this section. The
operating system may intend to maintain a respective status flag with respect to the specific
file. This file will further be examined with respect to the different processes which will be
attempted before writing has started (Verma, Bhardwaj and Yadav 2016). However, within
an environment where file-sharing persists, without the supervision of the operating system, a
significant lock file needs to be maintained which is to be read in respect to the application
level which will further determine the status of the file. This will help the deadlock situation
to be prevented with respect to the file systems.
Question 2:
In the database system, a deadlock occurs when more than one database sessions have some
data in the locked state (Silberschatz, Gagne and Galvin 2018). If a database session request
for data to lock, which is get locked by another database session, in this situation, deadlock
arises. Since the session is waiting for each other to release the lock and can be able to update
their session and unlock the session. In this scenario, nothing will happen since both the
sessions are waiting for each other and are called deadlock.
When a fund may be transferred between the two accounts using the following stages:
lock A ( I ) update A ( I ) unlock A ( I )
lock A ( J ) update A ( J ) unlock A ( J )
In the above scenario, there are two account A ( I ) and A( J ). Let’s us assume that the
account A re1quests for a transaction to lock using lock A ( I ). And call another transaction

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COMPUTER ORGANISATION AND ARCHITECTURE
A ( J ) to lock some data in order to run the transaction (Siahaan 2016). If the first account
(say A) holds any data or resources when executing the session, and second account (say, B)
requires same resources to execute the transaction, both the sessions are waiting for each
other to release the lock and waiting indefinitely period of time. In this situation, a deadlock
occurs.
However, in the above system the account A request for a resource to lock(i), then update the
session and unlock(i) it. And then the next account B request for the resource to lock(j), then
update the session and unlock(j) it. Therefore, both the sessions need not be waits for each
other to get the resource, and deadlock does not occur.
Question 3:
Waiting time – The waiting time calculates total time required by a process to finish the task.
The waiting time is potentially described to be the time that is necessarily spent by a
significant process that is depicted to be waiting within the sectors of the ready queue that are
trying to get back to the CPU for processing. In other terms, the waiting time is depicted with
respect to the time, indifference of the burst time and turnaround time.
WT = (TAT – BT)
TAT – Turnaround Time
BT – Burst Time
WT – Waiting Time