Midterm 1 FRQ
Due Oct 28 at 10am Points 80 Questions 8
Available Oct 28 at 8am – Oct 28 at 10am about 2 hours Time Limit 90 Minutes
Instructions
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This is the FRQ exam
Read carefully! This text will also be on the Canvas exam as well.
Hello students,
Welcome to the CSE130 Midterm 1! Please keep in mind these instructions before you hit start:
1. There are two exams. You must complete both of these exams in order to complete the entire exam. Both exams have a hard time limit of 90 minutes each.
1. DRC accommodations have been noted and those who are eligible will be provided with extra time respectively.
2. The examination window starts at 8:00 AM PST and ends at 10:00 AM PST. You are allowed to start either exam’s 90-minute timer within this window.
3. You are not allowed to collaborate on the exam.
4. This exam is open book and open notes.
5. There are ~15 MC questions (barring any last-minute removals) and 8 FRQs, please read each question carefully before answering.
You are expected to hit submit for both exams BEFORE 10:00 AM PST. There is a 15 minute time window after 9:45 AM PST to allow for submissions in case of network connectivity issues. If you choose to submit at 10:01 AM PST and fail to submit due to network connectivity issues, you are at fault for waiting until the last minute.
We anticipate that you should budget your time as follows. Keep in mind that this is not a hard limit, but our predicted time allocation for each question:
15 MC x 3 mins = 45 mins
8 FRQ x 5 min = 40 mins
Total: 85 minutes
If you open the exam and do not see any questions, please try a different browser or Incognito Mode.
YOU ARE RESPONSIBLE FOR HITTING SUBMIT FOR THE EXAM. WE CANNOT GUARANTEE A GRADE FOR AN EXAM THAT IS NOT SUBMITTED.
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DO NOT CONTACT US ON DISCORD DURING THE EXAM.
IF YOU HAVE QUESTIONS RELATED TO THE EXAM, PLEASE ASK US IN A PRIVATE POST ON PIAZZA. PUBLIC POSTS WILL BE DELETED WITH UTMOST PREJUDICE.
After the exam, do not discuss exam content on discord or Piazza until the DRC students have finished. We will make an announcement of when you are free to discuss the exam’s contents. We expect this time to be approximately 11:30 AM PST.
This quiz was locked Oct 28 at 10am. Attempt History
Attempt Time Score
Attempt Time Score
LATEST Attempt 1 77 minutes 57 out of 80
Correct answers are hidden.
Score for this quiz: 57 out of 80 Submitted Oct 28 at 9:45am This attempt took 77 minutes.
Question 1
7 / 10 pts
How are buffers used in computer systems? What are some considerations that you would make when choosing a buffer size? What are the tradeoffs of having a large buffer size?
Your Answer:
A buffer contains data that is stored for a short amount of time, typically in the memory. The purpose of a buffer is to hold data right before it’s used. Computer programs use buffers to store data while they are running and protocol stacks in computer network use buffer to store an amount of unpacked packets. The consideration will be when choosing a buffer size, the size should be proportional to the typical samples of the system. Also, the size of buffer should be acceptable to the whole system. When buffer size goes bigger, it can indeed store more data that could be possibly used, yet the searching efficiency in buffer is then sacrificed. Too big buffer could be bloated and even lead to the collapse of a system.
The considerations can help with more insights and so does tradeoffs
Question 2
10 / 10 pts
Provide four examples of virtualization in computer systems. For each, explain what kind of virtualization (e.g., multiplexing, aggregation, or emulation) it is an example of, and why.
Your Answer:
Website: Multiplexing
RAM disk: emulation
virtual memory: multiplexing RAID: aggregation
If the peak load of the websites is less than what a single server computer can support, then providers often prefer to use a single server to host many websites. That’s multiplexing
virtual memory is also an multiplexing for its host as it can split out an independent memory space.
In RAID, a number of disks are aggregated together in a clever way that provides an identical interface to the one of a single disk, but together the disks provide improved performance and durability.
A RAM disk provides the same interface as a physical disk but stores blocks in memory instead of on a disk platter. RAM disks can therefore read and write blocks much faster than a physical disk.
Question 3
8 / 10 pts
What is “Hard Modularity”? Describe the pros and cons of designing a hard modular system.
Your Answer:
Hard modularity physically divides units or functionalities into separate microservices, libraries or artifacts.
Question 4
8 / 10 pts
Contrast what it means to bind a name versus what it means to resolve a name.
Your Answer:
Bind a name is to associate an entity, like data, instructions and codes, with a reference. Binding is intimately connected with scoping, as scope determines which names bind to which objects – at which locations in the program code and in which one of the possible execution paths. On the other hand, name resolution refers to the retrieval of the underlying numeric values corresponding to name entities.
Examples of each would’ve helped
Pro: Provide simplification for hardware design, Simplify the maintenance; lower lifecycle costs
Con: Unlike soft modularity that are more feasible to change, the incompatibility in hard modularity are difficult to change unless use new hardware or new way of hard modularity. And users have to give up more requirements or preferences with modularity
Explanation on both pros and cons would’ve helped
Question 5
1 / 10 pts
Exactly-once delivery using bounded storage is impossible. But we are undaunted! Sketch how you might implement exactly-once delivery in an unreliable network, using minimal storage.
Question 6
10 / 10 pts
What is multiplexing? Give two examples of virtualization via multiplexing. Explain your choices.
Your Answer:
Multiplexing means the process of creating many pieces of virtual objects in one physical instance. For example, Website. If the peak load of the websites is less than what a singer server computer can support, then providers often prefer to use ONE single server to host many websites. The second example will be virtual memory. It’s also an multiplexing for its host as it can split out an independent memory space in a single physical space.
Your Answer:
We could use at most once guarantee. When a message is not delivered at all, or delivered but lost before any state changes occur in the recipient, leaving the recipient in the same sate it was before receiving the event. The at most once guarantee means that we either deliver a message successfully or not deliver it at all. This is a straightforward guarantee to implement and support because it involves the smallest effort or storage used.
don’t follow
Question 7
6 / 10 pts
Define the three fundamental abstractions of computer systems. For each, what are their attributes? Give an example of each.
Your Answer:
Question 8
7 / 10 pts
Complex systems existed long before the invention of computers, yet computer systems have fundamental differences that make their complexity more difficult to control. Discuss two ways in which computer systems differ fundamentally from physical systems.
Your Answer:
1. Emergent properties. Computer system develop so fast that many brand new concepts and attributes added into system. To maintain descent utilization, complexity is then introduced in a quadratic scale.
2. Propagation of effects. Some physical systems might also propagate profoundly the effects, yet it’s limited to its propagation speed. However, computer system are connected mostly with optical fiber, the propagation speed in computer systems could be the light speed. Thus, the effects could be rapidly propagated and make influences.
Need more exaplanation
Quiz Score: 57 out of 80
the memory, the interpreter, and the communication links. Memory is the system component that remembers data values for use in computation. Example: RAID and file system. The interpreter are the active elements of a computer system, they perform the actions that constitute computations. Example: Pentium 4; disk controller. Communication link provides a way for information to move between physically separated components. Example: Ethernet.
There is no mention of attributes
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