A. Suppose we plot the occurrence of file modification times versus locations on

Question

A. Suppose we plot the occurrence of file modification times versus locations on secondary storage on a disk drive that was purchased as used equipment at a computer store.

i) Suppose we discover there were a lot of modification times for a period of time, then gap of one year with no modifications, and then a lot of modifications lasting until the present. What is the most likely explanation of this behavior?

ii) Suppose we discover there was a steady increase in the disk block number of the modified areas of a drive over time. What is the most likely explanation of this behavior?

iii) Suppose we discover that nearly all activity is every Wednesday night at 2am. What is the most likely purpose of the drive?

iv) Suppose we discover that most activity is around 1600 every day. What is the most likely purpose of the drive?

B. Suppose we have a process that takes T units of time total.

i. If we split it into threads evenly, assume each thread will require S units of time in overhead where S is a fixed number. Suppose we split the process into N threads. How much of a speedup will we get if the processes execute simultaneously on different processors, as a function of N?

ii. Now assume each thread will require k*N units of time in overhead if we split the process into N threads. How much time will it take to run if the processes executes simultaneously on different processors, as a function of N?

iii. For part (ii) estimate the value of N in terms of T and k that gives the maximum speedup.

C. Suppose we follow these rules for memory management: (1)put a new file you are ordered to load in the lowest-numbered area of free memory that while hold all of it; (2) if there is not enough contiguous space to put a file, put as much as you can in the largest available space, then as much as you can in the next largest available space, and so on; (3) if a file in memory increases in size, split it where it overlaps into already-allocated memory and put the fragment in the lowest-numbered area of free memory that will hold all of it. Suppose we have a memory size 1 GB and the following events occur:

Explanation / Answer

sent back to a storage place outside the chip, such as the computer

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.