Data Storage

Question 1

What is the basic element of digital storage called?

Answer 1

A bit (from binary digit).

Question 2

What are bits grouped together into?

Answer 2

Sequences called cells.

Question 3

What is a cell of 8 bits called?

Answer 3

A byte

Question 4

What are other common cell sizes and what are they called?

Answer 4

A sequence of 16 bits is often called a word, and a sequence of 32 or 64 bits may be called a long word.

Question 5

What does the store consist of?

Answer 5

The store consists of a collection of cells.

Question 6

How is each cell in the store identified?

Answer 6

Each cell in the store is given an address, usually a positive integer starting at zero and going up.

Question 7

What is the smallest addressable unit of a store?

Answer 7

A cell

Question 8

What makes up the contents of a cell?

Answer 8

The states of the bits of a cell

Question 9

How is it more normal to represent cell contents?

Answer 9

It is more normal to represent the states as binary digits and write the cell contents as 0s and 1s, for example 001011101.

Question 10

What do the symbols A/B or 0/1 represent in cell contents?

Answer 10

Whether written as A and B or as 0 and 1, they are just representations of the two states of the device.

Question 11

What is unique about each cell in the store?

Answer 11

Each cell in the store has a unique address that identifies it.

Question 12

How are cell addresses numbered in a store with m cells?

Answer 12

Addresses are numbered from 0 to (m−1) for a store with m cells.

Question 13

Once a cell has been located at a specific address, what can be done with it?

Answer 13

Once located, a cell’s contents can be examined or changed.

Question 14

What is sequential access?

Answer 14

In sequential access, the time to access a cell with a given address depends on the address of the cell just accessed.

Have to go in order, cannot just go to whatever address you want like in RAM

Question 15

What is random access memory (RAM)?

Answer 15

What is random access memory (RAM)?

Question 16

What type of memory does main memory use?

Answer 16

Main memory uses DRAM.

Question 17

What type of memory does cache memory use?

Answer 17

Cache memory uses SRAM.

Question 18

Why can’t we tell what cell contents represent just by looking at them?

Answer 18

The contents of cells are simply bit patterns, so it is impossible to tell by looking at them whether they represent data or instructions.

Question 19

In a von Neumann architecture, what do the contents of cells at different addresses represent?

Answer 19

In a von Neumann architecture, the contents of some addresses represent instructions, while others represent data.

Question 20

What are addresses themselves, and where can they be stored?

Answer 20

Addresses are positive integers, and they themselves can be stored in cells as pieces of data.

Question 21

What is an address space?

Answer 21

An address space is the range of addresses a system or CPU can use

Question 22

Can the same address refer to different locations?

Answer 22

Yes, the same address may refer to different locations in different address spaces.

Question 23

What determines the size of an address space?

Answer 23

The length of the addresses determines the size of the address space.