Exercises On Process Management Due In First Week Of Class 7
Exercises Process Management Due First Class Week 72 Give An Origi
Exercises: process management (due first class week 7) 2. Give an original “real life†example (not related to a computer system environment, not discussed in our textbook or in lecture) of each of these concepts: deadlock, starvation, and race. 5. Using the narrow staircase example from the beginning of this chapter, create a list of features or actions that would allow people to use it without causing deadlock or starvation. 14.
As discussed in this chapter, a system that is in an unsafe state is not necessarily deadlocked. Explain why this is true. Give an example of such a system (in an unsafe state) and describe how all the processes could be completed without causing deadlock to occur. 16. Given the four primary types of resources—CPU, memory, secondary storage, and files—select for each one the most suitable technique described in this chapter to fight deadlock and briefly explain why you choose it ___________________________________________________________________________ Exercises: device management (due first class week 8) 3.
Explain the differences between blocking and buffering. 7. Minimizing the variance of system response time is an important goal, but it does not always prevent an occasional user from suffering indefinite postponement. What mechanism would you incorporate into a disk scheduling policy to counteract this problem and still provide reasonable response time to the user population as a whole? Explain your answer.
8. Explain the difference between buffering and spooling. 9. Under light loading conditions, every disk scheduling policy discussed in this chapter tends to behave like one of the policies discussed in this chapter. Which one and why?
12a. Disk track requests are not usually equally or evenly distributed. For example, the tracks where the disk directory resides are accessed more often than those where the user’s files reside. Suppose that you know that 50 percent of the requests are for a small, fixed number of tracks. Which one of the scheduling policies presented in this chapter would work best under these conditions? Explain your answer. Exercises: file management (due first class week 9) 3. Is device independence important to the File Manager? Explain why or why not. 6.
Files can be formatted with fixed length fields or variable length fields. In your opinion, would it be feasible to combine both formats in a single storage medium? Explain the reasons for your answer. 14. Compare and contrast dynamic memory allocation with the allocation of files in secondary storage.
Exercises: security basics (due first class week . Give three examples of excellent passwords and explain why each would be a good choice to protect a system from unauthorized users. 2. Give three advantages and disadvantages of password generator software. Would you recommend the use of such software for your own system? Explain why or why not. 7. Many users are required to log into several networks and thus have multiple passwords, which are difficult to remember. Name three ways that a user can manage these password requirements and compare the advantages and disadvantages of each. Which one you would use, and why?
Sample Paper For Above instruction
The concepts of deadlock, starvation, and race conditions are fundamental to understanding process management in computing systems, yet they can be vividly illustrated through real-life scenarios outside the realm of computer systems. This paper explores these concepts through relatable examples and addresses strategies to prevent deadlock and starvation, especially in situations like narrow staircase use, and discusses techniques for resource management, scheduling, and security considerations.
Real-Life Examples of Deadlock, Starvation, and Race
Deadlock: Imagine a situation where two individuals, Alice and Bob, are in a narrow alleyway, each waiting for the other to move aside to pass. Neither wants to back up because it would be awkward, leading to a standstill. Here, both are deadlocked because neither can proceed until the other moves, but neither will move first.
Starvation: Consider a busy cafeteria with several tables. A waiter consistently delivers meals to the same group of VIP guests, leaving other patrons waiting endlessly for their turn because the waiter prioritizes the VIPs, which results in starvation among the regular guests.
Race Condition: Two people attempting to cross a one-lane bridge from opposite ends simultaneously exemplify a race condition. Without a traffic control system, both might step onto the bridge simultaneously, leading to a collision—an unpredictable and risky scenario akin to a race condition in processes.
Preventing Deadlock and Starvation in the Narrow Staircase
To allow people to use a narrow staircase without causing deadlock or starvation, certain features must be incorporated. Implementing a waiting queue ensures orderly passage—people take turns entering the staircase in sequence, preventing deadlock. A maximum waiting time can be established so that no individual waits indefinitely—this prevents starvation. Clear signage and signals can be used to coordinate movement, ensuring that people do not block each other or wait unnecessarily long, thus avoiding deadlock and starvation altogether.
Unsafe States and Deadlock Prevention
A system that is in an unsafe state is not necessarily deadlocked because an unsafe state merely indicates that there is a potential for deadlock, but it has not actually occurred yet. For instance, consider a system with limited resources and multiple processes requesting resources. If the current allocation could lead to a situation where processes prevent each other from proceeding, the system is unsafe. However, if the system employs techniques like resource allocation graphs or banker’s algorithm, it can detect unsafe states and preempt processes or adjust allocations to ensure all processes complete without deadlock.
An example would be a printing queue where several print jobs are waiting. If resources such as printers and paper are limited, the system could misallocate resources temporarily, putting it in an unsafe state. Nonetheless, by carefully monitoring resource allocation and denying requests that lead to unsafe states, the system can still process all jobs without deadlock.
Techniques for Fighting Deadlock in Different Resources
CPU: Preemptive scheduling techniques, such as priority scheduling with aging, help prevent deadlock by granting CPU resources based on process priority and ensuring no process monopolizes the CPU for too long.
Memory: The use of the Banker's algorithm can prevent deadlock in memory management by allocating memory in a way that avoids unsafe states, ensuring processes only proceed when safe.
Secondary Storage: For secondary storage devices like disks, the elevator algorithm (SCAN algorithm) optimizes disk head movement and prevents deadlock by scheduling requests in an ordered manner.
Files: File locking mechanisms such as strict two-phase locking prevent deadlock by ensuring that resources are granted in a manner that avoids circular wait conditions.
Differences Between Buffering and Spooling
Buffering involves temporarily storing data in memory during transfer between two devices or processes to compensate for speed mismatches, enhancing efficiency. Spooling, on the other hand, involves queuing data—in particular, print jobs—on secondary storage (like disk) until the device (like a printer) is ready to process them, allowing multiple jobs to be stored and processed sequentially.
Disk Scheduling Policies and Their Efficiency
Under light load conditions, disk scheduling policies such as First-Come, First-Served (FCFS) tend to behave similarly because the request volume is low, and the order of requests is seldom optimized. However, algorithms like Shortest Seek Time First (SSTF) may perform better under certain circumstances to reduce seek time, but as load decreases, the differences diminish.
Managing Disk Requests with Uneven Distribution
When a significant portion of disk requests—say 50%—target a small set of tracks, the C-SCAN (Circular SCAN) policy would perform best. This is because C-SCAN provides a more uniform wait time for requests and prevents starvation by rotating the disk head around in a circular manner, ensuring that requests for heavily accessed tracks are serviced efficiently without indefinite delays.
Device Independence and File Formatting
Device independence is crucial to the File Manager because it allows files to be accessed uniformly across different hardware devices and storage mediums, providing flexibility, portability, and easier management. Combining fixed-length and variable-length fields within a single storage medium is feasible but complex; it requires careful management of space and offsets to ensure data integrity and efficiency.
Dynamic Memory Allocation vs Secondary Storage Allocation
Dynamic memory allocation involves managing RAM at runtime, providing fast access and flexibility but with potential fragmentation issues. Conversely, file allocation on secondary storage involves managing data persistence and larger storage spaces, often with higher latency but more stable and durable data storage. Both methods require careful design to optimize performance and resource utilization.
Password Examples and Security Management
Effective passwords should be random, complex, and difficult to guess. Examples include: "7x!Qp2#Vb9", "mZ$4&cL8@X", and "P@55w0rd!2023". Each combines uppercase and lowercase letters, numbers, and special characters, making them resistant to brute-force attacks. Password generator software automates the creation of such complex passwords, offering high strength but also potential management challenges and security risks if stored insecurely.
Advantages include creating strong passwords efficiently, while disadvantages relate to potential security vulnerabilities if generated passwords are stored improperly or software is compromised. Use of such software should be cautious, ideally combined with secure password management tools.
To manage multiple passwords across different networks, users can employ password managers, mnemonic techniques, or biometric authentication. Password managers, such as LastPass or Dashlane, offer the advantage of securely storing complex passwords but may present risks if the master password is compromised. Mnemonics facilitate recall but may be less secure if predictable. Biometric methods provide ease of access but can raise privacy concerns.
I would prefer using a reputable password manager because it balances security and convenience by storing complex passwords encrypted and accessible only via a strong master password.
Conclusion
Understanding process and device management concepts through real-world analogies enriches comprehension and application. Strategies like resource allocation algorithms and security protocols are vital in maintaining efficient, deadlock-free, and secure systems. The importance of combining technological solutions with proper management practices cannot be overstated in both computer and real-life operations.