Network modem question

Question

How would I solve the following can anyone help me.I know MIPS is basically how many instruction the processor can do per second but what should I do?

Assume that we are receiving a message across a network using a modem with a rate of 56,000 bits/second. Furthermore assume that we are working on a workstation with an instruction rate of 500 mips. How many instructions can the processor execute between the receipt of each individual bit of the message?

Answer 1

There are not enough details in the question. Yuval's answer gives the basic arithmetic answer. I'll just add that usually modems do not transfer the information "as-is" but encode it (see Asynchronous serial communication).

The most common encoding is 8N1, which means 10 symbols are sent per 1 byte of the message. The baud rate (56,000) is the number of symbols per second, rather than the number of bits per second.

So 8 bits of the message take 10 symbols, that is 1/5600 second. 1 bit takes 1/44800 sec. During that time, with 500MIPS you have $\approx 11200$ instructions.

(of course, if the rate is indeed 56000 bits/sec, then the 8/10 factor is not necessary.)

Answer 2

Hint: Suppose that the processor manages to execute $N$ instructions between the receipt of each individual bit. Executing the $N$ instructions takes time $T_1$. The time interval between the receipt of each individual bit is $T_2$. Set up an inequality and solve for $N$.