Andrew login ID Use block letters Full Name Use block letters 15 213 18 243 Fall 2010 Final Exam Friday December 10 2010 Instructions Make sure that your exam is not missing any sheets then write your Andrew login ID and full name on the front Please write using clear block letters This exam is closed book closed notes although you may use two 8 1 2 x 11 sheets of paper with your own notes You may not use any electronic devices The exam has a maximum score of 98 points The problems are of varying difficulty The point value of each problem is indicated Good luck 1 20 2 10 3 06 4 08 5 09 6 10 7 07 8 06 9 10 10 06 11 06 TOTAL 98 Page 1 of 22 Problem 1 20 points Short answer and multiple choice questions on a variety of stimulating and refreshing topics 1 Label the following networking system calls 1 2 3 4 or 5 in the order they should be called 2 pts label with an X if the call is not used a blank will receive no credit listen connect accept socket bind Client Server The remaining questions are multiple choice Write the correct answer for each question in the following table 1 X 11 2 3 4 5 6 7 8 9 10 12 13 14 15 16 17 18 19 20 X 2 Which of the following is NOT a universal property of reader writer locks a Readers can only look at a shared item writers can also modify it b If a writer has access to the item then no other thread also has access c Any number of readers can read the item at the same time d A writer waiting for an RW lock will get preference over subsequent read requests 3 Starvation in relation to threads refers to a A thread waiting for a lock indefinitely b A semaphore that gets locked but the thread never unlocks it after use c A thread is spawned but never joins the main thread when finished d A process fails to spawn a new thread because it s hit the maximum number of threads allowed 4 How does x86 assembly store the return value when a function is finished a The ret instruction stores it in a special retval register b By convention it is always in eax c It is stored on the stack just above the ebp of the callee d It is stored on the stack just above all the arguments to the function Page 2 of 22 5 In IEEE floating point what would be an effect of allocating more bits to the exponent part by taking them from the fraction part a You could represent fewer numbers but they could be much larger b You could represent the same numbers but with more decimal places c You could represent both larger and smaller numbers but with less precision d Some previously representable numbers would now round to infinity 6 Consider the following two blocks of code found in separate files main c int i 0 int main foo return 0 foo c int i 1 void foo printf d i What will happen when you attempt to compile link and run this code a It will fail to compile b It will fail to link c It will raise a segmentation fault d It will print 0 e It will print 1 f It will sometimes print 0 and sometimes print 1 7 Which of the following is an example of external fragmentation a A malloc ed block needs to be padded for alignment purposes b A user writes data to a part of the heap that isn t the payload of a malloc ed block c There are many disjoint free blocks in the heap d A user malloc s some heap space and never frees it 8 Which of the following is NOT the default action for any signal a The process terminates all of its children b The process terminates and dumps core c The process terminates d The process stops until restarted by a SIGCONT signal Page 3 of 22 9 Which of the following is FALSE concerning x86 64 architecture a A double is 64 bits long b Registers are 64 bits long c Pointers are 64 bits long d Pointers point to locations in memory that are multiples of 64 bits apart 10 Consider the following block of code int main int a 213 int i int j 15 for i 0 i 213 i a i i return 0 a 0 1 Which of the following instances of bad style is present a Dead code b Magic numbers c Poor indentation d All of the above Page 4 of 22 11 Consider the following structure declarations on a 64 bit Linux machine struct RECORD long value2 double value char tag 3 struct NODE int ref count struct RECORD record union double big number char string 12 mix Also a global variable named my node is declared as follows struct NODE my node If the address of my node is 0x6008e0 what is the value of my node record tag 1 a 0x6008f8 b 0x6008fa c 0x6008f9 d 0x6008f5 e 0x6008f1 12 With reference to the previous question what is the size of my node in bytes a 48 b 44 c 40 d 42 e 50 13 Which of the following x86 instructions can be used to add two registers and store the result without overwriting either of the original registers a mov b lea c add d None of the above Page 5 of 22 14 Which of these uses of caching is not crucial to program performance a Caching portions of physical memory b Caching virtual address translations c Caching virtual addresses d Caching virtual memory pages e None of the above that is they are all crucial 15 Assuming all the system calls succeed which of the following pieces of code will print the word Hello to stdout a int fd open hoola txt O RDWR dup2 fd STDOUT FILENO printf Hello fflush stdout b int fd open hoola txt O RDWR dup2 fd STDOUT FILENO write STDOUT FILENO Hello 5 c int fd open hoola txt O RDWR dup2 fd STDOUT FILENO printf Hello d int fd open hoola txt O RDWR dup2 STDOUT FILENO fd write fd Hello 5 e int fd open hoola txt O RDWR dup2 fd STDOUT FILENO write fd Hello 5 16 Consider the following piece of code Note that the file name is the same for both calls to open and assume the file one txt exists int fd open one txt O RDWR int fd2 open one txt O RDONLY Which of the following statement is true a fd and fd2 will share the same file offset b fd2 will be invalid because you cannot have two open file descriptors referring to the same file at the same time c Both fd and fd2 will have an initial file offset that is set to the end of the file d …
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