OS Chapter 8 - Virtual Memory
9) To overcome the problem of doubling the memory access time, most virtual memory schemes make use of a special high-speed cache for page table entries called a __________ .
TLB(Translation Lookaside Buffer)
11) With __________ , a page is brought into main memory only when a reference is made to a location on that page.
demand paging
11) The _________ policy results in the fewest number of page faults. A) Optimal B) FIFO C) Clock D) LRU
a
2) _________ is the virtual storage assigned to a process. A) Virtual address space B) Virtual address C) Real address D) Address space
a
3) __________ is the range of memory addresses available to a process. A) Address space B) Real address C) Virtual address D) Virtual address space
a
5) The _________ states the process that owns the page. A) process identifier B) control bits C) page number D) chain pointer
a
In SVR4 and Solaris systems, the memory management scheme that manages memory allocation for the kernel is called the _________ .
kernel memory allocator
The __________ policy replaces the page in memory that has not been referenced for the longest time.
LRV(Lowest Relative Value)
14) Linux makes use of a three-level page table structure consisting of the following types of tables: page directory, page table, and __________ .
page middle directory
The __________ provides a virtual memory capability that allocates page frames in main memory to processes and also allocates page frames to disk block buffers.
paging system
7) Because a process executes only in main memory, that memory is referred to as ____________ .
real memory
5) The portion of a process that is actually in main memory at any time is defined to be the ______ of the process.
resident set
10) The technique where the processor is equipped with hardware that allows it to interrogate simultaneously a number of TLB entries to determine if there is a match on page number is referred to as __________ .
associative mapping
8) __________ is transparent to the programmer and eliminates external fragmentation providing efficient use of main memory. A) Hashing B) Paging C) Segmentation D) Thrashing
b
9) The _________ determines when a page should be brought into main memory. A) page fault B) fetch policy C) working set D) resident set management
b
_________ is where modified process pages can be written out at the time of replacement, or a precleaning policy can be used, which clusters the output activity by writing out a number of pages at once. A) Load control B) Cleaning policy C) Placement policy D) Replacement policy
b
1) The address of a storage location in main memory is the __________ . A) address space B) virtual address space C) real address D) virtual address
c
12) A _________ chooses only among the resident pages of the process that generated the page fault in selecting a page to replace. A) global replacement policy B) page replacement policy C) local replacement policy D) page placement policy
c
6) A _________ is issued if a desired page is not in main memory. A) paging error B) page replacement policy C) page fault D) page placement policy
c
7) _________ allows the programmer to view memory as consisting of multiple address spaces. A) Paging B) Locality C) Segmentation D) Resident set management
c
10) With _________ pages other than the one demanded by a page fault are brought in. A) slab allocation B) thrashing C) hashing D) prepaging
d
13) The _________ algorithm requires a use bit to be associated with each page in memory. A) page placement B) working set C) VSWS D) page fault frequency
d
4) The __________ structure indexes page table entries by frame number rather than by virtual page number. A) hash table B) segment table C) page table D) inverted page table
d
_________ is the concept associated with determining the number of processes that will be resident in main memory. A) Virtual memory manager B) Page fault frequency C) LRU policy D) Load Control
d
3) The size of virtual storage is limited by the addressing scheme of the computer system and by the amount of __________ available.
secondary memory
10) Segments may be of unequal, indeed dynamic, size.
t
12) One way to counter the potential performance problems of a variable-allocation global scope policy is to use page buffering.
t
14) A precleaning policy writes modified pages before their page frames are needed so that pages can be written out in batches.
t
15) UNIX is intended to be machine independent; therefore its memory management scheme will vary from one system to the next.
t
9) The design issue of page size is related to the size of physical main memory and program size.
t
T/F 2) The addresses a program may use to reference memory are distinguished from the addresses the memory system uses to identify physical storage sites.
t
T/F 3) Most of the memory management issues confronting the operating system designer are in the area of paging when segmentation is combined with paging.
t
Virtual memory allows for very effective multiprogramming and relieves the user of the unnecessarily tight constraints of main memory.
t
8) When the system spends most of its time swapping pieces rather than executing instructions it leads to a condition known as _________ .
thrashing
6) A __________ policy allows the number of page frames allocated to a process to be varied over the lifetime of the process.
variable allocation
1) The address assigned to a location in virtual memory to allow that location to be accessed as though it were part of main memory is the __________ .
virtual address
2) _________ is a storage allocation scheme in which secondary memory can be addressed as though it were part of main memory.
virtual memory
4) The __________ policy treats the page frames allocated to a process as a circular buffer and pages are removed in round robin style.
FIFO
11) The page currently stored in a frame may still be replaced even when the page is locked.
f
13) The PFF policy evaluates the working set of a process at sampling instances based on elapsed virtual time.
f
4) Segmentation is not visible to the programmer.
f
5) The placement policy determines where in real memory a process piece is to reside.
f
7) The principle of locality states that program and data references within a process do not tend to cluster.
f
8) The smaller the page size, the greater the amount of internal fragmentation.
f
The size of virtual storage is limited by the actual number of main storage locations.
f
