Operating Systems Final
Under what circumstances do page faults occur? Describe the actions taken by the operating system when a page fault occurs
A page fault occurs when an access to a page that has not been brought into main memory takes place. The operating system verifies the memory access, aborting the program if it is invalid. If it is valid, a free frame is located and I/O is requested to read the needed page into the free frame. Upon completion of I/O, the process table and page table are updated, and the instruction is restarted
The following is a page table for a system with 12-bit virtual and physical addresses and 256-byte pages. Free page frames are to be allocated in the order 9, F, D. A dash for a page frame indicates that the page is not in memory. Convert the following virtual addresses to their equivalent physical addresses in hexadecimal. All numbers are given in hexadecimal. In the case of a page fault, you must use one of the free frames to update the page table and resolve the logical address to its corresponding physical address. 0x2A1 0x4E6 0x94A 0x316
0x2A1: Page number = highest 4 bits = highest nibble= 0x2 = decimal 2Frame number corresponding to page 2= 0xAThus, physical address, obtained by replacing the page-nibble with frame-nibble, is= 0xAA1 0x4E6: Page number = highest 4 bits = highest nibble= 0x4 = decimal 4Now, there is no frame mapped to page 4. So, the first free frame 0x9 is brought in, and the mapping updated in the page-table.Thus, physical address, obtained by replacing the page-nibble with frame-nibble, is= 0x9E6 0x94A: Page number = highest 4 bits = highest nibble= 0x9 = decimal 9Frame number corresponding to page 9= 0x1Thus, physical address, obtained by replacing the page-nibble with frame-nibble, is= 0x14A 0x316: Page number = highest 4 bits = highest nibble= 0x3 = decimal 3Now, there is no frame mapped to page 3. So, the next free frame 0xF is brought in, and the mapping updated in the page-table.Thus, physical address, obtained by replacing the page-nibble with frame-nibble, is= 0xF16
Consider the page table for a system with 12-bit virtual and physical addresses and 256-byte pages. The list of free page frames is D,E,F (that is, D is at the head of the list, E is second, and F is last). A dash for a page frame indicates that the page is not in memory. Convert the following virtual addresses to their equivalent physical addresses in hexadecimal. All numbers are given in hexadecimal. 9EF 111 700 0FF
256-byte pages = 2^8, so 8 bits is the offset 12-bit virtual addresses = 4 + 8bits for offset 9EF -> 0EF 1001 11101111 9->0 111 -> 211 0001 00010001 1->2 700 -> D00 0111 00000000 7->- (D is the next available frame) 0FF -> EFF 0000 11111111 0->- (E if the next available frame)
Given the logical address 0xAEF9 (in hexadecimal) with a page size of 256 bytes, what is the page number? A) 0xAE B) 0xF9 C) 0xA D) 0x00F9
A) 0xAE
What is random-access time?
It is the time to move disk arm to desired cylinder (seek time) and time for desired sector to rotate under the disk head (rotational latency).
What is the cause of thrashing? How does the system detect thrashing? Once it detects thrashing, what can the system do to eliminate this problem?
Thrashing is caused by under allocation of the minimum number of pages required by a process, forcing it to continuously page fault. The system can detect thrashing by evaluating the level of CPU utilization as compared to the level of multiprogramming. It can be eliminated by reducing the level of multiprogramming.
True or False: Contiguous allocation of a file is defined by the address of the first block and length (in block units) of the file.
True
True or False: FIFO page replacement can suffer from Belady's anomaly.
True
True or False: In swapping with paging technique, individual pages of a process are swapped in or out.
True
True or False: LRU and OPT are stack algorithms that do not suffer from Belady's Anomaly.
True
True or False: The ARM architecture uses both single-level and two-level paging.
True
What is internal fragmentation?
allocated memory may be slightly larger than requested memory; this size difference is memory internal to a partition, but not being used
Assume a system uses 2-level paging and has a TLB hit ratio of 90%. It requires 15 nanoseconds to access the TLB, and 85 nanoseconds to access main memory. What is the effective memory access time in nanoseconds for this system? A) 22 B) 108.5 C) 30.5 D) 117
B) 108.5 2m -ma + e = 2(85) - 85(.9) + 15 = 170 - 76.5 + 25 = 108.5
Assume the value of the base and limit registers are 1200 and 350 respectively. Which of thefollowing addresses is legal? A) 355 B) 1200 C) 1551 D) all of the above
B) 1200
What is the size of the bit vector of a 1TB disk with 512-byte blocks? A) 8 MB B) 268 MB C) 2 MB D) 28 MB
B) 268 MB
Given the reference string of page accesses: 1 2 3 4 2 3 4 1 2 1 1 3 1 4 and a system with three page frames, what is the final configuration of the three frames after the LRU algorithm is applied? A) 1, 3, 4 B) 3, 1, 4 C) 4, 1, 2 D) 1, 2, 3
B) 3, 1, 4 1 - - p 1 2 - p 1 2 3 p 4 2 3 p 4 1 3 p 4 1 2 p 3 1 2 p 3 1 4 p
Suppose we have the following page accesses: 1 2 3 4 2 3 4 1 2 1 1 3 1 4 and that there are three frames within our system. Using the FIFO replacement algorithm, what is the number of page faults for the given reference string? A) 14 B) 8 C) 13 D) 10
B) 8 - - - 1 - - p 1 2 - p 1 2 3 p 1 2 3 p 4 2 3 p 4 1 3 p 4 1 2 p 3 1 2 p 3 4 2 p
Belady's anomaly states that ____. A) giving more memory to a process will improve its performance B) as the number of allocated frames increases, the page-fault rate may decrease for all page replacement algorithms C) for some page replacement algorithms, the page-fault rate may decrease as the number of allocated frames increases. D) for some page replacement algorithms, the page-fault rate may increase as the number of allocated frames increases
D) for some page replacement algorithms, the page-fault rate may increase as the number of allocated frames increases
In a blocking system call, the execution of a process is suspended A) until the process is woken up by some other process. B) until a fixed amount of time has elapsed. C) the kernel raises the priority of that process. D) when the I/O has completed.
D) when the I/O has completed.
External fragmentation is A) when there is some unused memory that cannot be allocated to a process. B) when the amount of available memory is less than the size of a process. C) when a process is broken up into smaller parts for memory allocation. D) when there is enough total memory space to satisfy a request but the available spaces are not contiguous.
D) when there is enough total memory space to satisfy a request but the available spaces are not contiguous.
______________ is used to implement a file system. A. A boot control block B. A volume control block C. A directory structure. D. all of the above
D. all of the above
True or False: A 32-bit logical address with 8kb page size will have 1,000,000 entries in a conventional page table.
False
True or False: A relocation register is used to check for invalid memory addresses generated by a CPU.
False
True or False: Fragmentation does not occur in a paging system.
False
True or False: Hierarchal page tables are appropriate for 64-bit architectures.
False
True or False: Inverted page tables require each process to have its own page table.
False
True or False: Reentrant code cannot be shared.
False
The SSTF scheduling algorithm _____________________________.
services the request with the minimum seek time.
An address generated by a CPU is referred to as a _____________. A) physical address B) logical address C) post relocation register address D) Memory-Management Unit (MMU) generated address
B) logical address
With _______ locking, once a process acquires an exclusive lock, the operating system will prevent any other process from accessing the locked file. A) temporary B) mandatory C) shared D) exclusive
B) mandatory
If execution time binding is used, A) logical addresses of process may change over time but physical addresses remain the same. B) physical addresses of process may change over time but logical addresses remain the same. C) both physical and logical addresses may change over time. D) both physical and logical addresses remain the same over time.
B) physical addresses of process may change over time but logical addresses remain the same.
The SCAN scheduling algorithm ________. A) services the request with the minimum seek time B) services the request next to the current head positionin the direction of the head movement C) chooses to service the request furthest from the current head position D) services the request next to the current head positionin the opposite direction of the head movement
B) services the request next to the current head positionin the direction of the head movement
A sign of thrashing is A) the CPU utilization increases as the degree of multiprogramming is increased. B) the CPU utilization decreases as the degree of multiprogramming is increased. C) the CPU utilization increases as the number of pages allocated to each process is increased. D) the CPU utilization decreases as the number of pages allocated to each process is increased
B) the CPU utilization decreases as the degree of multiprogramming is increased.
Reentrant code is easier to share when paging is used, because A) each process can modify that code its own way. B) the code doesn't change during execution. C) the code changes are identical for each process. D) All of the above.
B) the code doesn't change during execution.
Consider a disk queue holding requests to the following cylinders in the listed order: 116, 22, 3, 11, 75, 185, 100, 87. Using the FCFS scheduling algorithm, what is the order that the requests are serviced, assuming the disk head is at cylinder 88 and moving upward through the cylinders? A) 116 - 22 - 3 - 11 - 75 - 185 - 100 - 87 B) 100 - 116 - 185 - 87 - 75 - 22 - 11 - 3 C) 87 - 75 - 100 - 116 - 185 - 22 - 11 - 3 D) 100 - 116 - 185 - 3 - 11 - 22 - 75 - 87
A) 116 - 22 - 3 - 11 - 75 - 185 - 100 - 87
If the base register is loaded with value 12345 and limit register is loaded with value 1000,which of the following memory address access will not result in a trap to the operating system? A) 12500 B) 12200 C) 13346 D) 12344
A) 12500
Consider a logical address with 18 bits used to represent an entry in a conventional page table. How many entries are in the conventional page table? A) 262,144 B) 1,024 C) 1,048,576 D) 18
A) 262,144 (2^18)
Which of the following disk head scheduling algorithms does not take into account the current position of the disk head? A) FCFS B) C-SCAN C) SCAN D) All scheduling algorithms take into account the current position of the disk head
A) FCFS
Which of the following is true of the Java programming language in relation to protection? A) When a class is loaded, the JVM assigns the class to a protection domain that gives the permissions of that class. B) It does not support the dynamic loading of untrusted classes over a network. C) It does not support the execution of mutually distrusting classes within the same JVM. D) Methods in the calling sequence are not responsible for requests to access a protected resource
A) When a class is loaded, the JVM assigns the class to a protection domain that gives the permissions of that class.
Computing systems need cache because A) accessing main memory is slow and cache speeds it up. B) register access is slow and cache speeds it up. C) main memory is expensive and cache offsets the cost. D) All of the above
A) accessing main memory is slow and cache speeds it up.
A translation look-aside buffer is used to A) cache page table entries. B) store the address of the page table in memory. C) size of the logical address space of the currently running process.D store page size.
A) cache page table entries.
Object means __________ A) hardware object or software object B) process or threat C) software object only D) process only
A) hardware object or software object
The Second-Chance algorithm A) is same as FIFO algorithm if all pages in memory have been referenced at least once since the last page fault. B) is same as FIFO algorithm if none of the pages in memory have been referenced since the last page fault. C) is same as LRU algorithm if all pages in memory have been referenced at least once since the last page fault. D) is same as LRU algorithm if none of the pages in memory have been referenced since the last page fault.
A) is same as FIFO algorithm if all pages in memory have been referenced at least once since the last page fault.
A page out operation A) moves a page from memory to the backing store. B) moves a page from the backing store to memory. C) moves a page from one frame to another. D) deletes a page from the backing store.
A) moves a page from memory to the backing store.
The protection bit in a page table A) provides protection against unauthorized updates in the page table. B) marks a page table as read-only or read-write. C) marks a frame as read-only or read-write. D) All of the above
A) provides protection against unauthorized updates in the page table.
The basic file systems _______________ A) reads and writes physical blocks on the storage device. B) tracks unallocated blocks and provides them the when it is required. C) manages directory structure. D) is responsible for protection.
A) reads and writes physical blocks on the storage device.
What are the two components of positioning time? A) seek time + rotational latency B) transfer time + transfer rate C) effective transfer rate - transfer rate D) cylinder positioning time + disk arm positioning time
A) seek time + rotational latency
Anonymous memory of a process refers to A) the pages not associated with the binary executable file of the process. B) the pages associated with the binary executable file of the process. C) the pages associated with the static data of the process. D) the pages that cannot be swapped out of the physical memory.
A) the pages not associated with the binary executable file of the process.
If an instruction modifies several different locations, a page fault can be handled by A) using temporary registers to hold the values of overwritten locations. B) loading multiple pages in advance. C) incorporating special hardware. D) terminating the process.
A) using temporary registers to hold the values of overwritten locations.
First-fit
Allocate the first hole that is big enough. Searching can start either at the beginning of the set of holes or at the location where the previous first-fit search ended. We can stop searching as soon as we find a free hole that is large enough.
Worst-fit
Allocate the largest hole. Again, we must search the entire list, unless it is sorted by size. This strategy produces the largest leftover hole, which may be more useful than the smaller leftover hole from a best-fit approach
Best-fit
Allocate the smallest hole that is big enough. We must search the entire list, unless the list is ordered by size. This strategy produces the smallest leftover hole.
What is the difference between Logical and Physical Addresses?
An address generated by the CPU is commonly referred to as a logical address, whereas the address seen by the memory unit, the one loaded into memory-address register, is physical address.
Given the reference string of page accesses: 1 2 3 4 2 3 4 1 2 1 1 3 1 3 and a system with three page frames, what is the final configuration of the three frames after the OPT algorithm is applied? A) 1, 3, 4 B) 1, 2, 3 C) 2, 3, 4 D) 1, 2, 1
B) 1, 2, 3 1 - - p 1 2 - p 1 2 3 p 4 2 3 p 1 2 3 p
Consider a disk queue holding requests to the following cylinders in the listed order: 116, 22, 3, 11, 75, 185, 100, 87. Using the SCAN scheduling algorithm, what is the order that the requests are serviced, assuming the disk head is at cylinder 88 and moving upward through the cylinders? A) 116 - 22 - 3 - 11 - 75 - 185 - 100 - 87 B) 100 - 116 - 185 - 87 - 75 - 22 - 11 - 3 C) 87 - 75 - 100 - 116 - 185 - 22 - 11 - 3 D) 100 - 116 - 185 - 3 - 11 - 22 - 75 - 87
B) 100 - 116 - 185 - 87 - 75 - 22 - 11 - 3
__________ is the algorithm implemented on most systems. A) FIFO B) LRU C) OPT D) None of the above
B) LRU
Which of the following is true about dynamic storage allocation? A) Worst fit provides the best storage utilization. B) First fit requires less time for allocation than worst fit on average. C) Best fit is clearly better than first fit in terms of time and storage utilization. D) First fit is clearly better than best fit in terms of time and storage utilization.
B) First fit requires less time for allocation than worst fit on average.
________________ is not a protection mechanism. A) System Integrity Protection B) Intrusion Prevention C) System-Call Filtering D) Sandboxing
B) Intrusion Prevention
Which of the following statement is correct? A) Base register holds the size of a process. B) Limit register holds the size of a process. C) Base and limit registers can be loaded by the standard load instructions in the instruction set. D) Any attempt by a user program to access memory at an address higher thanthe base register value results in a trap to the operating system
B) Limit register holds the size of a process.
What is the difference between mechanisms and policies? A) Mechanisms determine what will be done, while policies decide when it will be done B) Mechanisms determine how something will be done, while policies decide what will be done C) Mechanisms determine how something will be done, while policies decide why something will be done D) Mechanisms determine what will be done, while policies decide how it will be done
B) Mechanisms determine how something will be done, while policies decide what will be done
Optimal page replacement ____. A) is the page-replacement algorithm most often implemented B) is used mostly for comparison with other page-replacement schemes C) can suffer from Belady's anomaly D) requires that the system keep track of previously used pages
B) is used mostly for comparison with other page-replacement schemes
In Additional-Reference-Bits algorithm, A) the least-recently used page is identified very efficiently on a page fault. B) a group of pages that have not been used recently are efficiently identified. C) a page that has been referenced most recently is identified. D) None of the above.
B) a group of pages that have not been used recently are efficiently identified.
A protection domain is a collection of access rights, each of which is ___________________ A) a pair <object-name, list-of-users> B) a pair <object-name, rights-set> C) a triplet <object-name, user, rights-set> D) a triplet <object-name, process_id, rights-set>
B) a pair <object-name, rights-set>
The owner right allows ___________ A) addition of new rights only B) addition of new rights and removal of some rights C) removal of some rights only D) none of the above
B) addition of new rights and removal of some rights
Which of the following is NOT a technique used for managing power consumption in mobile devices? A) Power collapse. B) chilling with natural sources such as lake water, and solar panels. C) Component level power management. D) Wakelocks.
B) chilling with natural sources such as lake water, and solar panels.
In a swap map in Linux A) counter value 0 indicates that the page slot is occupied by a swapped page. B) counter value 5 indicates that the page slot is occupiedand the page is shared by five processes. C) counter value -1 indicates that the page slot is available. D) counter value -5 indicates that the page slot was occupiedby a page that was shared by five processes, and is now available.
B) counter value 5 indicates that the page slot is occupiedand the page is shared by five processes.
A free-frame list A) is a set of all frames that are filled with all zeros. B) is a set of all frames that are currently unallocated to any process. C) is a set of all frames that are currently being shared by at least two processes. D) is a set of all frames that are used for stack and heap memory.
B) is a set of all frames that are currently unallocated to any process.
Suppose a program is operating with execution-time binding and the physical address generated is 300. The relocation register is set to 100. What is the corresponding logical address? A) 199 B) 201 C) 200 D) 300
C) 200
Consider a disk queue holding requests to the following cylinders in the listed order: 116, 22, 3, 11, 75, 185, 100, 87. Using the SSTF scheduling algorithm, what is the order that the requests are serviced, assuming the disk head is at cylinder 88 and moving upward through the cylinders? A) 116 - 22 - 3 - 11 - 75 - 185 - 100 - 87 B) 100 - 116 - 185 - 87 - 75 - 22 - 11 - 3 C) 87 - 75 - 100 - 116 - 185 - 22 - 11 - 3 D) 100 - 116 - 185 - 3 - 11 - 22 - 75 - 87
C) 87 - 75 - 100 - 116 - 185 - 22 - 11 - 3
Consider a disk queue holding requests to the following cylinders in the listed order:210, 67, 11, 99, 87, 90, 19, 150. Using the C-SCAN scheduling algorithm,what is the order that the requests are serviced,assuming the disk head is at cylinder 88 and moving upward through the cylinders? A) 87 - 90 - 99 - 67 - 19 - 11 - 150 - 210 B) 210 - 67 - 11 - 99 - 87 - 90 - 19 - 150 C) 90 - 99 - 150 - 210 - 11 - 19 - 67 - 87 D) 90 - 99 - 150 - 210 - 87 - 67 - 19 - 11
C) 90 - 99 - 150 - 210 - 11 - 19 - 67 - 87
Which of the following technique is well suited to support very large address space, e.g. 64-bit address space? A) Inverted page tables B) Hierarchical page tables C) Clustered page tables D) All of the above
C) Clustered page tables
If the starting address location changes, in which of the following cases, the program has to be recompiled? A) Execution time binding. B) Load time binding. C) Compile time binding D) Both compile and load time bindings.
C) Compile time binding
______________ is the method of binding instructions and data to memory performed by most general-purpose operating systems. A) Interrupt binding B) Compile time binding C) Execution time binding D) Load-time binding
C) Execution time binding
Solid state disks (SSDs) commonly use the _____________ disk scheduling policy. A) SSTF B) SCAN C) FCFS D) LOOK
C) FCFS
Which of the following is true about choosing an appropriate page size? A) Larger page size results in reducing total I/O. B) Smaller page size reduces the number of page faults. C) Larger page size reduces I/O time. D) Larger page size results in less total allocated memory
C) Larger page size reduces I/O time.
Which of the following is FALSE about swap space use? A) Swap space may be used to hold an entire process image. B) Swap space may be used to store only pages that have been pushed out of main memory. C) Swap space may be used to store the file system. D) Swap space can be a dedicated swap partition, a swap file,or a combination of swap partitions and swap files.
C) Swap space may be used to store the file system.
A capability list for a domain is ____________________ A) a list of operations together with the list of processes allowed to run the operations on those objects. B) a list of objects together with the list of processes allowed to access those objects. C) a list of objects together with the operations allowed on those objects. D) a list of triplet <object, process, rights>
C) a list of objects together with the operations allowed on those objects.
In demand paging, A) a page loaded in memory may never be accessed. B) all pages that a program will access during execution are loaded in memory in the beginning. C) a page is loaded in memory only when it is needed during execution. D) a page is loaded in memory just before it is needed.
C) a page is loaded in memory only when it is needed during execution.
Indexed allocation A) supports direct access B) does not suffer from external fragmentation. C) all of the above D) none of the above
C) all of the above
The following characteristics of disks make them convenient for being the secondary storage: A) it is possible to read a block from the disk, modify the block, and write it back into the same place B) a disk can access directly any block of information it contains C) all of the above D) none of the above
C) all of the above
Technique used to improve I/O efficiency by temporarily storing copies of data is called A) spooling. B) buffering. C) caching. D) memory mapping.
C) caching.
Stack algorithms are a class of page replacement algorithms that A) are implemented using stacks. B) are guaranteed to incur the least number of page faults. C) do not suffer from Belady's anomaly. D) are guaranteed to incur no more page faults than FIFO page replacement algorithm
C) do not suffer from Belady's anomaly.
Suppose the size of a process is 10,000 bytes and the relocation register is loaded with value 5000,which of the following memory address this process can access? A) logical address 10,350 B) physical address 4,500 C) physical address 10,350 D) None of the above
C) physical address 10,350
Counting based page replacement algorithms are not commonly used, because A) they only approximate LRU. B) they are expensive to implement, even though they incur the least number of page faults. C) they do not approximate OPT replacement very well and their implementation is expensive. D) they do not approximate OPT replacement very well, even though they are easy to implement.
C) they do not approximate OPT replacement very well and their implementation is expensive.
The most preferred method of swapping a process is A) to swap using the file system. B) to copy an entire file to swap space at process startup and then perform demand paging from the swap space. C) to demand-page from the file system initially but to write the pages to swap space as they are replaced. D) None of the above
C) to demand-page from the file system initially but to write the pages to swap space as they are replaced.
Consider a disk queue holding requests to the following cylinders in the listed order: 116, 22, 3, 11, 75, 185, 100, 87. Using the C-SCAN scheduling algorithm, what is the order that the requests are serviced, assuming the disk head is at cylinder 88 and moving upward through the cylinders? A) 116 - 22 - 3 - 11 - 75 - 185 - 100 - 87 B) 100 - 116 - 185 - 87 - 75 - 22 - 11 - 3 C) 87 - 75 - 100 - 116 - 185 - 22 - 11 - 3 D) 100 - 116 - 185 - 3 - 11 - 22 - 75 - 87
D) 100 - 116 - 185 - 3 - 11 - 22 - 75 - 87
Suppose we have the following page accesses: 1 2 3 4 2 3 4 1 2 1 1 3 1 4 and that there are three frames within our system. Using the FIFO replacement algorithm, what will be the final configuration ofthe three frames following the execution of the given reference string? A) 4, 1, 3 B) 3, 1, 4 C) 4, 2, 3 D) 3, 4, 2
D) 3, 4, 2
Using __________-bit pointers limits the size of a file to 4 GB. A) 64 B) 128 C) 256 D) 32
D) 32
An advantage of virtual memory is that A) a program can be much larger than the size of physical memory. B) the programmers can concentrate programming the problem instead of worryingabout the amount of physical memory available. C) it provides a way to execute a program that is only partially loaded in memory. D) All of the above
D) All of the above
A frame table stores A) which frames are allocated. B) which frames are free. C) total number of frames. D) All of the above.
D) All of the above.
Buffering in I/O is used to A) cope with a speed mismatch between the producer and consumer of a data stream. B) provide adaptations for devices that have different data-transfer sizes. C) support copy semantics for application I/O. D) All of the above.
D) All of the above.
The working set strategy A) swaps out a process if OS cannot allocate enough pages to accommodate its working set. B) swaps in a new process if there is enough memory available to accommodate its working set. C) keeps the degree of multiprogramming as high as possible while preventing thrashing. D) All of the above.
D) All of the above.
Which of the following is true about the strategy that uses page fault frequency (PFF) to prevent thrashing? A) A new page is allocated to a process if PFF is too high. B) A page is deallocated from a process if the PFF is too low. C) A new process may be swapped in if PFF is too low. D) All of the above.
D) All of the above.
A drawback of equal or proportional allocation is that A) they are very expensive to compute. B) the processes that arrive earlier get more pages than the processes arriving later. C) the allocation varies according to the degree of multiprogramming. D) a high-priority process is treated the same as a low-priority process.
D) a high-priority process is treated the same as a low-priority process.
Lock bit is NOT used for which of the following cases: A) the page that is being used for I/O. B) some OS pages. C) a new page that has just been brought in. D) a page that belongs to a high priority process.
D) a page that belongs to a high priority process.
The dirty (modify) bit identifies A) a page that has been corrupted. B) a page that needs to be reloaded when accessed. C) a page that is shared by multiple processes. D) a page that has been modified since it was loaded.
D) a page that has been modified since it was loaded.
What pointer is used for writing a file? A) memory pointer B) seek pointer C) shared--file pointer D) current-file-position pointer
D) current-file-position pointer
Memory compression is a useful alternative to paging A) when the system has slow magnetic disks but not faster SSDs. B) when the compression algorithm is can achieve the best possible compression ratio. C) when the speed of the compression algorithm fastest. D) even when the system has faster SSDs.
D) even when the system has faster SSDs.
True or False: Disk controllers do not usually have a built-in cache.
FALSE
True or False: There is a 1:1 corresponding between the # of entries in the TLB and the number of entries in the page table.
FALSE
