chapter 4 computer architecture

4.1 What are the differences among sequential access, direct access, and random access?

Answer :
• Sequential access: Memory is organized into units of data, called records. Access must be made in a specific linear sequence.
• Direct access: Individual blocks or records have a unique address based on physical location. Access is accomplished by direct access to reach a general vicinity plus sequential searching, counting, or waiting to reach the final location.
• Random access: Each addressable location in memory has a unique, physically wired-in addressing mechanism. The time to access a given location is independent of the sequence of prior accesses and is constant.

 4.2 What is the general relationship among access time, memory cost, and capacity?

Answer : Faster access time, greater cost per bit; greater capacity, smaller cost per bit; greater
capacity, slower access time.

4.8 What is the distinction between spatial locality and temporal locality?

Spatial locality refers to the tendency of execution to involve a number of memory locations that are clustered.
Temporal locality refers to the tendency for a processor to access memory locations that have been used recently.