question stringlengths 33 1.06k | subject stringclasses 1
value | choices listlengths 4 4 | answer class label 4
classes |
|---|---|---|---|
The access matrix approach to protection has the difficulty that | college_computer_science | [
"the matrix, if stored directly, is large and can be clumsy to manage",
"it is not capable of expressing complex protection requirements",
"deciding whether a process has access to a resource is undecidable",
"there is no way to express who has rights to change the access matrix itself"
] | 0A |
TCP protocol is responsible (among other things) for | college_computer_science | [
"Routing packets through the network",
"Reliable delivery of packets between directly connected machines",
"Reliable delivery of large (multi-packet) messages between machines that are not necessarily directly connected",
"Dealing with differences among operating system architectures"
] | 2C |
Which of the following is NOT a reasonable justification for choosing to busy-wait on an asynchronous event? | college_computer_science | [
"The wait is expected to be short.",
"A busy-wait loop is easier to code than an interrupt handler.",
"There is no other work for the processor to do.",
"The program executes on a time-sharing system."
] | 3D |
The language {ww | w in (0 + 1)*} is | college_computer_science | [
"not accepted by any Turing machine",
"accepted by some Turing machine, but by no pushdown automaton",
"accepted by some pushdown automaton, but not context-free",
"context-free, but not regular"
] | 1B |
In the NoNicks operating system, the time required by a single file-read operation has four nonoverlapping components:
disk seek time-25 msec
disk latency time-8 msec
disk transfer time- 1 msec per 1,000 bytes
operating system overhead-1 msec per 1,000 bytes + 10 msec
In version 1 of the system, the file read retrieved... | college_computer_science | [
"1:4",
"1:3.5",
"1:1",
"1.1:1"
] | 1B |
Which of the following comes closest to being a perfectly secure encryption scheme? | college_computer_science | [
"The Caesar Cipher, a substitution cipher",
"DES (Data Encryption Standard), a symmetric-key algorithm",
"Enigma, a transposition cipher",
"One-time pad"
] | 3D |
Of the following problems concerning a given undirected graph G, which is currently known to be solvable in polynomial time? | college_computer_science | [
"Finding a longest simple cycle in G",
"Finding a shortest cycle in G",
"Finding ALL spanning trees of G",
"Finding a largest clique in G"
] | 1B |
The IP protocol is primarily concerned with | college_computer_science | [
"Routing packets through the network",
"Reliable delivery of packets between directly connected machines",
"Reliable delivery of large (multi-packet) messages between machines that are not necessarily directly connected",
"Dealing with differences among operating system architectures"
] | 0A |
Of the following, which best approximates the ratio of the number of nonterminal nodes to the total number of nodes in a complete K-ary tree of depth N? | college_computer_science | [
"1/K",
"K-1/K",
"log_10 (1/N)",
"N-1/m"
] | 0A |
Languages with a structure that implements abstract data types (e.g., a C++ class) can prevent access to components of this structure by all operations except those that are part of this structure. However, definitions of such a structure often contain declarations of components of the structure (e.g., the header file ... | college_computer_science | [
"I only",
"III only",
"I and II only",
"II and III only"
] | 3D |
You want to cluster 7 points into 3 clusters using the k-Means Clustering algorithm. Suppose after the first iteration, clusters C1, C2 and C3 contain the following two-dimensional points: C1 contains the 2 points: {(0,6), (6,0)} C2 contains the 3 points: {(2,2), (4,4), (6,6)} C3 contains the 2 points: {(5,5), (7,7)} W... | college_computer_science | [
"C1: (3,3), C2: (4,4), C3: (6,6)",
"C1: (3,3), C2: (6,6), C3: (12,12)",
"C1: (6,6), C2: (12,12), C3: (12,12)",
"C1: (0,0), C2: (48,48), C3: (35,35)"
] | 0A |
Which of the following is usually NOT represented in a subroutine's activation record frame for a stack-based programming language? | college_computer_science | [
"Values of local variables",
"A heap area",
"The return address",
"Stack pointer for the calling activation record"
] | 1B |
Which of the following statements about a remote procedure call is true? | college_computer_science | [
"It is used to call procedures with addresses that are farther than 2^16 bytes away.",
"It cannot return a value.",
"It cannot pass parameters by reference.",
"It cannot call procedures implemented in a different language."
] | 2C |
A particular parallel program computation requires 100 seconds when executed on a single processor. If 40 percent of this computation is "inherently sequential" (i.e., will not benefit from additional processors), then the theoretically best possible elapsed times for this program running with 2 and 4 processors, respe... | college_computer_science | [
"20 and 10 seconds",
"30 and 15 seconds",
"50 and 25 seconds",
"70 and 55 seconds"
] | 3D |
Of the following, which best characterizes computers that use memory-mapped I/O? | college_computer_science | [
"The computer provides special instructions for manipulating I/O ports.",
"I/O ports are placed at addresses on the bus and are accessed just like other memory locations.",
"To perform an I/O operation, it is sufficient to place the data in an address register and call the channel to perform the operation.",
... | 1B |
Many cryptographic protocols base their security on assumptions about the computational difficulty of integer factorization. Integer factorization serves this purpose because we believe that | college_computer_science | [
"integer multiplication is a function whose inverse, factorization, remains difficult for a large class of inputs",
"P = NP",
"even if P = NP, integer factorization is still likely not to be polynomial-time computable",
"testing primality is computationally intractable"
] | 0A |
Which of the following sets of bit strings CANNOT be described with a regular expression? | college_computer_science | [
"All bit strings whose number of zeros is a multiple of five",
"All bit strings starting with a zero and ending with a one",
"All bit strings with an even number of zeros",
"All bit strings with more ones than zeros"
] | 3D |
Which of the following decimal numbers has an exact representation in binary notation? | college_computer_science | [
"0.1",
"0.2",
"0.3",
"0.5"
] | 3D |
Function signatures describe the types of the arguments to a function as well as the return value of the function. For instance, the addition function on reals has a signature of
add : real x real -> real
since it takes two real numbers and returns a real number. But, for a language that allows functions as return valu... | college_computer_science | [
"Currying can be applied to any function to the point where it has exactly one input argument.",
"Currying cannot be applied to functions of more than two arguments.",
"Currying cannot be applied to functions that return functions as arguments.",
"Currying cannot be applied w functions that haw arguments that... | 0A |
Consider the collection of all undirected graphs with 10 nodes and 6 edges. Let M and m, respectively, be the maximum and minimum number of connected components in any graph in the collection. If a graph has no selfloops and there is at most one edge between any pair of nodes, which of the following is true? | college_computer_science | [
"M = 10, m = 10",
"M = 10, m = 1",
"M = 7, m = 4",
"M = 6, m = 4"
] | 2C |
If a malicious process is granted temporary administrator-level access to a system | college_computer_science | [
"the threat is over as soon as the process is killed",
"the threat is over after the operating system is rebooted",
"the thread is over after rebooting the machine and replacing files that show a virus infection",
"the threat is often permanent until the entire disk is wiped clean"
] | 3D |
A "strictly binary tree" is a binary tree in which every node that is not a leaf has two children. Suppose that for a class of strictly binary trees there exists c > 0 such that, for any tree in the class, the ratio of the lengths of any two root-to-leaf paths is bounded above by c. Which of the following best characte... | college_computer_science | [
"h <= log2(N)",
"h = 1/c * log2(N)",
"h < c log2(N)",
"h > c log2(N)"
] | 2C |
Assume that any assignment statement can be executed in unit time. If as many identical processors as needed are used, what is the minimum number of time units needed to execute the assignments
A := B + C
B := A - B
C := A * E
D := A/F
E := B - C
F := A + B
with the same result as if the assignments were executed in th... | college_computer_science | [
"1",
"2",
"3",
"4"
] | 2C |
Two expressions E and F are said to be unifiable if there are substitutions for the variables of E and F that make the expressions lexically identical. In the following three expressions, only w, x, y, and z are variables.
I. f(w,w)
II. f(x,1)
III. f(y,g(z))
Which pairs of these expressions is (are) pairs of unifiable ... | college_computer_science | [
"(I, II) only",
"(I, III) only",
"(II, III) only",
"(I, II) and (I, III) only"
] | 3D |
Which of the following instruction-set features is NOT generally considered an obstacle to aggressive pipelining of an integer unit? | college_computer_science | [
"Condition codes set by every instruction",
"Variable-length encoding of instructions",
"Instructions requiring widely varying numbers of cycles to execute",
"Several different classes (sets) of registers"
] | 3D |
Let T (n) be defined by T(1) = 7 and T(n + 1) = 3n + T(n) for all integers n ≥ 1. Which of the following represents the order of growth of T(n) as a function of n? | college_computer_science | [
"Θ(n)",
"Θ(n log n)",
"Θ(n^2)",
"Θ(n^2 log n)"
] | 2C |
Two single-user workstations are attached to the same local area network. On one of these workstations, file pages are accessed over the network from a file server; the average access time per page is 0.1 second. On the other of these workstations, file pages are accessed from a local disk; the average access time per ... | college_computer_science | [
"1/1",
"5/4",
"5/3",
"10/5"
] | 1B |
Which of the following statements describe(s) properties of a purely segmented memory system?
I. It divides memory into units of equal size.
II. It permits implementation of virtual memory.
III. It suffers from internal fragmentation. | college_computer_science | [
"I only",
"II only",
"III only",
"I and III"
] | 1B |
Which of the following pairs of 8-bit, two's-complement numbers will result in overflow when the members of the pairs are added? | college_computer_science | [
"11111111, 00000001",
"00000001, 10000000",
"11111111, 10000001",
"10000001, 10101010"
] | 3D |
Two computers communicate with each other by sending data packets across a local area network. The size of these packets is 1,000 bytes. The network has the capacity to carry 1,000 packets per second. The CPU time required to execute the network protocol to send one packet is 10 milliseconds. The maximum rate at which ... | college_computer_science | [
"10,000 bytes/second",
"25,000 bytes/ second",
"100,000 bytes/ second",
"500,000 bytes/ second"
] | 2C |
Consider the following grammar.
S → ( S )
S → x
Which of the following statements is (are) true?
I. The grammar is ambiguous.
II. The grammar is suitable for top-down parsing.
III. The grammar is suitable for bottom-up parsing. | college_computer_science | [
"I only",
"II only",
"III only",
"II and III only"
] | 3D |
Hash tables can contribute to an efficient average-case solution for all of the problems described below EXCEPT: | college_computer_science | [
"Counting distinct values: Given a set of n keys, determine the number of distinct key values.",
"Dynamic dictionary: Support the operations of insert, delete, and search in a dictionary.",
"Range search: Given values a and b, find all the records whose key value is in the range a, b.",
"Symbol table lookup: ... | 2C |
Let A be a finite set with m elements, and let B be a finite set with n elements. The number of distinct functions mapping A into B is | college_computer_science | [
"n^m",
"n!/(n - m)!",
"n!",
"n!/(m!(n - m)!)"
] | 0A |
To compute the matrix product M_1M_2, where M_1 has p rows and q columns and where M_2 has q rows and r columns, takes time proportional to pqr, and the result is a matrix of p rows and r columns. Consider the product of three matrices N_1N_2N_3 that have, respectively, w rows and x columns, x rows and y columns, and y... | college_computer_science | [
"There is no such condition; i.e., they will always take the same time.",
"1/x + 1/z < 1/w + 1/y",
"x > y",
"1/w + 1/x < 1/y + 1/z"
] | 1B |
The hit ratio of a cache memory is the percentage of accesses (reads and writes) for which data are found in the cache. Write-through is a policy whereby every write operation updates main memory. Write-back is a policy whereby a write operation to a line found in the cache does not affect main memory until the line is... | college_computer_science | [
"Write-back usually results in a better hit ratio than write-through.",
"Write-through usually results in a better hit ratio than write-back.",
"The percentage of write operations resulting in a main memory operation will never be larger for write-back than for write-through.",
"The percentage of write operat... | 2C |
A particular disk unit uses a bit string to record the occupancy or vacancy of its tracks, with O denoting vacant and 1 denoting occupied. A 32-bit segment of this string has the hexadecimal value D4FE2003. The percentage of occupied tracks for the corresponding part of the disk, to the nearest percent, is | college_computer_science | [
"12%",
"25%",
"38%",
"44%"
] | 3D |
Which of the following statements about floating-point arithmetic is NOT true? | college_computer_science | [
"It is inherently nonassociative because some numbers have no exact representation.",
"It is inherently nonassociative because there have to be upper and lower bounds on the size of numbers.",
"Associativity can be achieved with appropriate roundoff conventions.",
"Some rational numbers have no exact represen... | 2C |
Of the following, which gives the best upper bound for the value of f(N) where f is a solution to the recurrence f(2N + 1) = f(2N) = f(N) + log N for N >= 1, with f(1) = 0? | college_computer_science | [
"O(log N)",
"O(N log N)",
"O(log N) + 0(1)",
"O((log N)^2)"
] | 3D |
Company X shipped 5 computer chips, 1 of which was defective, and Company Y shipped 4 computer chips, 2 of which were defective. One computer chip is to be chosen uniformly at random from the 9 chips shipped by the companies. If the chosen chip is found to be defective, what is the probability that the chip came from C... | college_computer_science | [
"2 / 9",
"4 / 9",
"1 / 2",
"2 / 3"
] | 3D |
Local caching of files is common in distributed file systems, but it has the disadvantage that | college_computer_science | [
"Temporary inconsistencies among views of a file by different machines can result",
"The file system is likely to be corrupted when a computer crashes",
"A much higher amount of network traffic results",
"Caching makes file migration impossible"
] | 0A |
Array A contains 256 elements of 4 bytes each. Its first element is stored at physical address 4,096.
Array B contains 512 elements of 4 bytes each. Its first element is stored at physical address 8,192.
Assume that only arrays A and B can be cached in an initially empty, physically addressed, physically tagged, direct... | college_computer_science | [
"0",
"256",
"1024",
"2048"
] | 2C |
At time 0, five jobs are available for execution on a single processor, with service times of 25, 15, 5, 3, and 2 time units. Which of the following is the minimum value of the average completion time of these jobs? | college_computer_science | [
"50",
"208/5",
"92/5",
"10"
] | 2C |
Let G = (V, E) be a connected, undirected graph, and let a and b be two distinct vertices in V. Let P_1 be the problem of finding a shortest simple path between a and b, and let P_2 be the problem of finding a longest simple path between a and b. Which of the following statements about P_1 and P_2 is true? | college_computer_science | [
"Both P_1 and P_2 can be solved in polynomial time.",
"P_1 can be solved in polynomial time but P_2 is not known to be solvable in polynomial time.",
"P_1 is not known to be solvable in polynomial time but P_2 can be solved in polynomial time.",
"It is not known whether either P_1 or P_2 can be solved in poly... | 1B |
A major advantage of direct mapping of a cache is its simplicity. The main disadvantage of this organization is that | college_computer_science | [
"it does not allow simultaneous access to the intended data and its tag",
"it is more expensive than other types of cache organizations",
"the cache hit ratio is degraded if two or more blocks used alternately map onto the same block frame in the cache",
"its access time is greater than that of other cache or... | 2C |
A 3-way, set-associative cache is | college_computer_science | [
"one in which each main memory word can be stored at any of 3 cache locations",
"effective only if 3 or fewer processes are running alternately on the processor",
"possible only with write-back",
"faster to access than a direct-mapped cache"
] | 0A |
Consider an object-oriented language in which all entities are objects. Two relationships arise: (1) the instance relationship, between an object and the class of which that object is a member, and (2) the subclass relationship, between a class and the superclass from which that class inherits properties. In such a lan... | college_computer_science | [
"one instance link and then zero or more subclass links",
"one or more instance links and then one or more subclass links",
"one or more instance links",
"one subclass link and then one or more instance links"
] | 0A |
Suppose that a certain software product has a mean time between failures of 10,000 hours and has a mean time to repair of 20 hours. If the product is used by 100 customers, what is its availability? | college_computer_science | [
"80%",
"90%",
"98%",
"99.80%"
] | 3D |
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