Can Someone please help with these questions

1. DEC's PDP-8 computer used a structure called Omnibus. Explain what it is and discuss the advantages and disadvantages of the use of Omnibus.

2. Explain the four techniques that are used in modern processors to exploit the raw speed of a processor which increases the performance of a processor.

3. A computer's CPU can execute a program in 2 minutes and 20 seconds. In order to shorten the execution time, we analysed the program and found that part of the program can be executed in parallel. It is estimated that 40% of the program can be done in parallel.

(a). If we execute the program with 4 identical CPUs, estimate the speedup and the time it will take to execute the program, assuming all others remain unchanged.

(b). Estimate the limit to the speedup.