. A thread differs from a process in that, among other things: (a) It can be created at a lower cost. (b) It provides mo

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. A thread differs from a process in that, among other things:
(a) It can be created at a lower cost. (b) It provides more data
isolation than a process. (c) Switching threads of one process is
faster than switching different processes. (d) Communication of
threads requires IPC mechanisms. (e) Processes can only be run by a
judge. 2. What error/problem occurs in the following code: from
threading import Thread, Lock l1 = Lock() l2 = Lock() def thr1():
with l1: with l2: print("Peek-a-boo 1!") def thr2(): with l2: with
l1: print("Peek-a-boo 2!") def main(): t1 = Thread(target=thr1) t2
= Thread(target=thr2) t1.start() t2.start() if _name_ == "_main_":
main() (a) Race condition. (b) Data starvation of one of the
threads. (c) Semaphores should be used instead of locks. (d)
Possibility of a deadlock. (e) No error - the program will
definitely work correctly.
3. What are (among other things) the differences between a
binary semaphore and a lock?
(a) A semaphore has information about which thread acquired it,
while a lock does not.
(b) A lock has information about which thread acquired it, while
a semaphore does not.
(c) A binary semaphore works more efficiently. (d) A semaphore
can be used in algorithms where another thread increments and
another decrements the semaphore; this is impossible for a lock.
(e) A semaphore only occurs at railroad crossings.
4. Among other things, what are the differences between sockets
using the TCP and UDP protocols?
(a) TCP has a smaller system overhead.
(b) UDP ensures that packets are delivered in the correct order,
while TCP does not.
(c) UDP can be used for multicast transmissions, while TCP
cannot.
(d) UDP is stateless, while TCP is not.
(e) There is no difference: these are the two names for the same
protocol.
5. In which application should we consider using UDP, instead of
TCP? (a) Video transmission. (b) Transmission of large binary data
files. (c) VoIP transmission. (d) Single packet transmission. (e)
It is always better to use UDP, because TCP sucks and nobody uses
it.
6. What are the advantages of the NFS filesystem? (a) Great
scalability on large clusters and supercomputers. (b) Simplicity
and high popularity. (c) Dynamic development in the recent years.
(d) Security achieved by data replication. (e) NFS has no
advantages and nobody uses it
. 7. DNS traditionally has been using UDP for: (a) Transferring
zone files. (b) Sending requests and responses. (c) Communications
using DNSSEC. (d) All transmissions. (e) None of the above.
8. What is the disadvantage of using threads to serve various
connections in a server? (a) Relatively hogh system overhead of a
thread. (b) Vulnerability to a DDoS attack, by enforcing creation
of an outrageous number of threads. (c) The threads do not assure
enough data separation. (d) This is forbidden by the law