Two of the most fundamental functions for dealing with interprocess communication are read() and write(). Consider the following otherwise valid C program: int r, pipeFDs[2];
char message[512];
pid_t spawnpid;

pipe(pipeFDs);
spawnpid = fork();

switch (spawnpid)
{
case 0:
close(pipeFDs[0]); // close the input file descriptor
write(pipeFDs[1], "hi process, this is the STUFF!!", 21);
break;

default:
close(pipeFDs[1]); // close output file descriptor
r = read(pipeFDs[0], message, sizeof(message));
printf("Message received from other: %s\n", message);
break;
}

Select each of the following answers that is correct. CAN BE MULTIPLE CHOICES...
(1) The read() call may block until data becomes available
(2) When the read() call returns, this one call will return all of the data that was sent through the pipe, which is different behavior than if this was a socket
(3) If the read() call blocks, the process will be suspended until data arrives
(4) The write() call will return before all of the data has been written, if the corresponding read() call blocks mid-transfer
(5) Pipes can fill, which will cause the write() call to block until the read() call is able to read data from the pipe

Which of the following had the greatest influence on opening the internet to the generly public

Consider a slotted aloha system, where the time slot equals the fixed duration of each packet. assume that there are 4 stations a, b,c, d sharing the medium. (a) stations a, b,c, d receive one packet each from higher layers at times 1.3, 1.5, 2.6,5.7 respectively. show which transmissions take place when, according to the slottedaloha protocol; describe all transmissions until all four packets have been successful. when needed, each station has access to the following sequence of random number, provided by a random number generator and drawn uniformly between 0 and 1: (1) station a draws numbers: 0.31, 0.27, 0.78, 0.9, 0.9, 0.11, 0. (2) station b draws numbers: 0.45, 0.28, 0.11, 0.83, 0.37, 0.22, 0. (3)station c draws numbers: 0.1, 0.2, 0.3, 0.4, 0. (4) station d draws numbers: 0.36, 0.77, 0.9, 0.1, 0.1, 0.1, 0.1, 0. (b) in slotted aloha, a station transmits in each time slot with a given probability. what probabilities would you assign to each of the four stations so as to: (i) maximize the efficiency of the protocol? (ii) maximize fairness among the four stations? (c) will the efficiency increase or decrease if we modify slotted aloha as follows: (i) get rid of slots and allow stations to transmit immediately? (ii) implement carrier sensing? (iii) implement collision detection? (iv) implement collision avoidance?

Whats three fourths of 15(this is supposed to be in math but i clicked too fast)