Summary
Summary COS3721 ASSIGNMENT 1 SOLUTIONS 2023
- Institution
- University Of South Africa (Unisa)
ASSIGNMENT 1 ASWERS FOR COS
[Show more]
Connected book
Book Title:
Author(s):
- Edition:
- ISBN:
- Edition:
Content preview
Assignment 1 Total marks 100Question-1 Coverage : Chapter 1 [10]
1) Direct memory access is used for high-speed I/O devices in order to avoid increasing the
CPU’s execution load.
a. How does the CPU interface with the device to coordinate the transfer? (2)
~ The CPU can initiate a direct memory Access (DMA) operation by writing values into special
registers that can be independently accessed by the device. The device initiates the corresponding
operation once it receives a command from the Central Processing Unit (CPU).
b. How does the CPU know when the memory operations are complete? (2)
~ It gets interrupted to indicate the completion of the operation. Both the device and the CPU can
be accessing memory simultaneously. The memory controller provides access to the memory bus in
a fair manner to these two entities
c. The CPU is allowed to execute other programs while the DMA controller is transferring
data. Does this process interfere with the execution of the user programs? If so, describe
what forms of interference are caused. (4)
~ The process does interfere with the program, The CPU might be unable to issue memory
operations at peak speeds since it has to compete with the device in order to obtain access to the
memory bus.
~ DMA can lead to memory fragmentation. This can cause performance issues when the CPU
attempts to allocate or access memory.
2) Describe two challenges of designing operating systems for mobile devices compare with
designing operating system for traditional PCs. (2)
~ Less processing power and fewer processors mean the operating system must carefully share
processors to applications.
~ Less storage capacity means the operating system must manage memory carefully.
Question 2: Operating-system structures [12]
1) Describe three general methods for passing parameters to the operating system. (6)
~ Pass parameters in registers
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through EFT, credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying this summary from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller elenaprowriter. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy this summary for R100,00. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
75759 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy summaries for 14 years now