Archive for category CpS 360
Operating Systems – Managing Protection & Security
Security has certainly become a very “hot topic” in operating system discussions these days. On the one hand we want/need our OS to provide shared access to information, but on the other hand we want to know that that information is kept away from others. Security is about balancing easy of access to information vs keeping things hidden & locked.
The key topics presented in Chapter 14 (the last chapter of the semester – yaa!!) are
- authentication
- authorization
- cryptography
The challenge presented is that software creates an almost impossible situation with regard to protecting against unauthorized acesss of resources. Yet it is by definition the job of an OS to manage those resources. Managing demands that the manager be in complete control of the resources. An OS protection mechanism demands that the designers of the OS consider all possible (past, current and future) software attacks upon resources. This is a most daunting task to be sure!
After reading this chapter, discuss the following questions in the comment section of this blog.
- The best authorization is no good without perfect authentication.
- Why is cryptography now playing such an important role in OS security?
- On the administration side of security, it is often very difficult to find the right settings for all resources and all users. The goal is 2-fold: 1) give the right access to everyone for everything they need 2) keep everyone out of stuff they don’t need. Discuss a mechanism that would assist an admin in accomplishing both these goals at the same time.
- A real challenge to OS security is balancing the demands of authorization with those of performance. Discuss this issue and present a balanced design solution.
- Explain the exact steps a client and server take in Kerberos to authenticate that a message is from the party it claims to be.
Open Source Impact on OS
Discuss the impact the open source definition has had & in the future will have on operating system development. Include in your discussion the concept of trusted software.
1. Do you think OSD has had a positive or negative impact on OS development? Include references to the history of OSD in your answer. In other words why has OSD had such an impact based upon issues presented in the OS Revolution video?
2. What about other types of software – has OSD had a similar impact on other types of software? why or why not?
3. What is the future of OSD on OS development? If you think OSD has had a positive impact on other types of software development then discuss what it will take for the impact to continue. Otherwise discuss what you think it would take for it to start having such a positive impact.
4. What is the future of OSD on other types of software? If you think OSD has had a positive impact on other types of software development then discuss what it will take for the impact to continue. Otherwise discuss what you think it would take for it to start having such a positive impact.
Be sure and include at least some of the points in open source definition in your discussion.
Trusted OS Software
The topic of trusted software wrt operating system design is introduced in chapter 3. Consider the relationship between trusted software, OS kernel, supervisor mode, system call, message passing, modularization, performance, monolithic kernel and microkernel.
1. What is the challenge of achieving trusted software?
2. What role does supervisor mode play in trusted software?
3. Compare system calls and message passing as they relate to a user process running in supervisor mode in order to execute OS functionality.
4. What is a microkernel and what advantage does it have over the standard kernel approach wrt trusted software?
5. What functionality does a microkernel provide and what functionality is provided outside the microkernel?
6. Why is performance in issue with the microkernel approach?
7. Why does modularization sacrifice performance?
CpS 360 First Day
I write this from the comfort of my home office, not because I don’t want to see your smiling faces, but my stomach decided to “catch the flu” so for your sakes as well as mine, I’m staying home today!
Here are a few links to get your started for this course:
The topic for today: What is an Operating System? Here are the questions I want you to ponder, after pondering them I want you to post a comment in which you do your best to attempt to answer each of the following thought provoking questions. Your posted comment will be assigned a grade as well as used for today’s class attendance.
- What is an Operating System?
- What does it do?
- Why do we need one?
- Suppose you just completed creating and building a brand new processor for which no software exists. Outline what you would need to do in order for your processor to become “marketable”.
You may use your textbook or any online resource to give you ideas for your posting. Please limit yourself to a SINGLE POST for today’s class.
Hint on posting your comment – write it up using your favorite text editor or word processor, then paste it into the comment block
ASSIGNMENT DUE MONDAY – Complete the Chapter 1 Reading Quiz in EClass (the registration key for this course is CPS360Spring08)