$1.(30$ points$)$ Multiple Choices

Write your answers in the boxes below:

$(1)$ Consider that a system uses $2-$level paging scheme and has a TLB hit ratio of $\backslash (90\backslash \%\backslash ).$ It requires $15$ nanoseconds to access the TLB$,$ and $100$ nanoseconds to access main memory. What is the effective memory access time for this system? $($A TLB hit directly results in page translation, i$.$e$.,$ frame number$)$

A$)115$ nanoseconds

B$)125$ nanoseconds

C$)135$ nanoseconds

D$)150$ nanoseconds

$(2)$ Consider a paging scheme with $32-$bit logical address and $4$KB page size. Suppose that a single$-$level page table is used with a page table entry $($PTE$)$ size of $4$ bytes, and each PTE contains $10$ control bits. What are the sizes of logical address space and physical address space, respectively?

A$)\backslash (4\backslash$mathrm$\{$~GB$\},8\backslash$mathrm$\{$~GB$\}\backslash )$

B$)\backslash (4\backslash$mathrm$\{$~GB$\},16\backslash$mathrm$\{$~GB$\}\backslash )$

C$)\backslash (8\backslash$mathrm$\{$~GB$\},8\backslash$mathrm$\{$~GB$\}\backslash )$

D$)\backslash (8\backslash$mathrm$\{$~GB$\},16\backslash$mathrm$\{$~GB$\}\backslash )$

$(3)$ Which of the following statements about Belady's Anomaly is TRUE?

A$)$ FIFO page replacement algorithm suffers from Belady's Anomaly

B$)$ LRU page replacement algorithm suffers from Belady's Anomaly

C$)$ OPT page replacement algorithm suffers from Belady's Anomaly

D$)$ All of the above

$(4)$ Which of the following statements about thrashing is FALSE?

A$)$ Thrashing leads to extremely high CPU utilization

B$)$ Thrashing occurs due to the locality of all processes exceeds the total memory

C$)$ Local page replacement strategy can limit the trashing within one process D$)$ Working set model can be leveraged to track the locality of the process to mitigate the thrashing problem

$(5)$ Consider a disk with average seek time is $4$ ms $,$ RPM is $6,000,$ transfer rate is $\backslash (100\backslash$mathrm$\{$MB$\}/\backslash$mathrm$\{$s$\}\backslash ),$ and a $1$ MB read occurs at a random location. The controller overhead is $1$ ms $.$ The effective bandwidth or transfer rate is:

A$)\backslash (150\backslash$mathrm$\{$MB$\}/\backslash$mathrm$\{$s$\}\backslash )$

B$)\backslash (100\backslash$mathrm$\{$MB$\}/\backslash$mathrm$\{$s$\}\backslash )$

C$)\backslash (50\backslash$mathrm$\{$MB$\}/\backslash$mathrm$\{$s$\}\backslash )$

D$)\backslash (25\backslash$mathrm$\{$MB$\}/\backslash$mathrm$\{$s$\}\backslash )$

$(6)$ Which of the following statements about RAID is FALSE?

A$)$ RAID$0$ is used to achieve high performance

B$)$ RAID$1$ is used to achieve high reliability

C$)$ Parity bits are used in some RAID levels

D$)$ We cannot simultaneously achieve high performance and high reliability with RAID

$(7)$ Which of the following statements about acyclic$-$graph directories is FALSE?

A$)$ Acyclic$-$graph directories support links pointing to an existing file

B$)$ Acyclic$-$graph directories allow aliasing

C$)$ Acyclic$-$graph directories do not bring extra complexity in identifying cycles

D$)$ Deleting a file may cause dangling pointers

$(8)$ Consider a file system stored on a disk with block size of $1024$ bytes. Suppose the disk address $($block number$)$ uses $4$ bytes. Please compute the total number of blocks required to allocate a file of size $100,350$ bytes under $($a$)$ contiguous and $($b$)$ indexed allocation.

A$)98$ and $99$

B$)99$ and $100$

C$)100$ and $110$

D$)100$ and $101$

$(9)$ Suppose process A has $10$ files open, process B has $6$ files open and process C has $8$ files open. $4$ files are shared among the three processes. How many entries are in the system$-$wide open$-$file tables?

A$)20$

B$)18$

C$)26$

D$)16$

$(10)$ A protection domain is a collection of access rights, each of which is

A$.$ a pair

B$.$ a pair

C$.$ a triplet

D$.$ a triplet