3.3 Data storage

Question 1

The memory and storage devices can be split up into two distinct groups. What are they?

Answer 1

1. Primary Storage
2. Secondary Storage (External & Internal)

Question 2

What are the properties of the primary storage?

Answer 2

• The primary storage is the main memory that is directly accessed by the CPU.
• It is internal to the computer (inside a computer).
  It has a faster access speed.
• It stores boot-up instructions and can hold data whilst being processed.
• It has both volatile and non-volatile.

Question 3

What are the examples of primary storage and their functions?

Answer 3

Examples: Random Access Memory (RAM) and Read Only Memory (ROM).

• The RAM stores programs and data that are currently in use, and the ROM stores boot-up instructions.
• The RAM is volatile, and ROM is non-volatile.

Question 4

What are some features of RAM?

Answer 4

• The RAM is much faster to write to or read from than other types of memory.
• The RAM normally has a larger capacity than ROM.

Question 5

Why do buffers use RAM?

Answer 5

The buffers use RAM since they need to be a fast memory, and the data only needs to be held temporarily.

Question 6

What are the two types of RAM technology?

Answer 6

• Dynamic RAM (DRAM)
• Static RAM (SRAM).

Question 7

What are the advantages of DRAM?

Answer 7

• DRAMs (Dynamic RAMs) are much less expensive to manufacture than SRAM(Static RAM)
• They have a higher storage capacity than SRAM.

Question 8

What is the use of DRAM?

Answer 8

DRAM is the most common type of RAM used in computers, except for high-speed areas.

Question 9

What are the advantages of SRAM?

Answer 9

• It is much faster than DRAM when it comes to data access, as the typical access time for SRAM is 25 nanoseconds, and for DRAM is 60 nanoseconds.
• It has lower power consumption.

Question 10

What is the use of SRAM, and give an example.

Answer 10

• SRAM is the most used technology in areas where absolute speed is essential.
• For example, the processor’s memory cache is the high-speed portion of the memory.

Question 11

What are some features of Read-Only Memory(ROM)?

Answer 11

• ROM normally has a smaller capacity than RAM.
• It is non-volatile or permanent memory (the contents of the memory remain even when the power to the ROM is turned off).

Question 12

What are some differences between RAM and ROM?

Answer 12

• The RAM is volatile, whereas the ROM is non-volatile.
• The RAM is temporary, whereas the ROM is permanent.
• The RAM normally has a larger capacity than ROM.

Question 13

What is meant by secondary storage, and describe its properties.

Answer 13

• The secondary storage is persistent memory that is not directly accessed by the CPU.
• It is necessary for more permanent storage of data.
• It can be internal or external to the computer.
• It has a slower access speed.
• It stores files, data, operating system, and software, etc., that can be accessed at a later stage.
• It is non-volatile only.

Examples: Hard Disk Drive (HDD) and Solid State Drive (SSD).

Question 14

What is off-line storage, and describe its properties.

Answer 14

• The off-line storage is not directly accessed by the CPU.
• It is necessary for more permanent storage of data.
• It is external to the computer (removable from a computer)
• It is used to store files as a backup.
• It is non-volatile memory that can be removed from a computer system.

Examples: CD, DVD, Blu-ray, USB flash memory/memory sticks, external HDD

Question 15

Give examples of Magnetic storage and solid-state storage (INTERNAL SECONDARY STORAGE)

Answer 15

MAGNETIC STORAGE: Hard Disk Drive (HDD)

SOLID-STATE STORAGE: Solid State Drive (SDD)

Question 16

Give examples of Magnetic storage, solid-state storage, and optical storage (OFF-LINE(EXTERNAL) SECONDARY STORAGE)

Answer 16

MAGNETIC: External HDD(Hard Disk Drive)

OPTICAL: CD Disk, DVD disk, and Blu-ray disc

Solid-state storage: Memory stick

Question 17

Is an internal Solid State Drive (SSD) an example of primary, secondary or off-line storage? Justify your choice.

Answer 17

• It is an example of secondary storage because it is non-volatile storage.
• It is not directly accessed by the CPU.

Question 18

How does magnetic storage operate?

Answer 18

• It uses platters which are divided into tracks & sectors.
• The data is read and written using electromagnets.

Question 19

How does optical storage operate?

Answer 19

• It uses lasers to create and read pits and lands.

Question 20

How does Solid-state storage operate?

Answer 20

• It uses NAND technology or NOR technology.
• The transistors are used as control gates & floating gates

Question 21

How does magnetic storage device store data?

Answer 21

• The storage device has platters, and data is stored on platters
• The platters are divided into tracks and sectors
• The storage platter is spun
• It has a read and write arm that moves across storage media.

Question 22

What are the advantages of Magnetic storage devices compared to solid-state storage devices?

Answer 22

• Magnetic storage devices are cheaper per unit of data
• Magnetic storage devices have more longevity; therefore, they can perform more read/write cycles.

Question 23

How does SSD store data?

Answer 23

• It uses flash memory
• It stores the data by flashing it onto the silicon chips
• It uses NAND or NOR technology
• The data is stored by controlling the flow of electrons using transistors, which are used as control gates and floating gates.

Question 24

What is the purpose of Virtual Memory?

Answer 24

• The secondary storage is used to extend the RAM (main memory) available so the CPU can access more memory space than the already available RAM space.

Question 25

Describe the process of paging.

Answer 25

- The main memory (RAM) is divided into equal-sized blocks, called page frames. - Each process that is executed is divided into blocks of the same size, called pages. - Each process has a page table that is used to manage the pages of this process. - It is used by memory management in the operating system to store and retrieve data from HDD or SSD and copy it into the RAM.

Question 26

Describe a suitable page-replacement algorithm.

Answer 26

First in-First-out

Question 27

What is disk-thrashing?

Answer 27

- Pages are required back in the RAM as soon as they are moved to disk. - There is a continuous swapping of the same pages.

Question 28

Software is being used to create 3D models, which often requires the use of virtual memory. Why is virtual memory needed for this process?

Answer 28

- It is needed to extend the RAM capacity to stop the 3D modelling software from freezing or crashing when the physical RAM is full. - It is needed to allow the computer to process the large amount of data required for 3D modelling.

Question 29

Define cloud storage.

Answer 29

- The cloud is an online data storage where the data is stored on off-site or remote servers. - It can be accessed remotely, and physical servers & storage are needed to store data in cloud storage.

Question 30

What are some advantages of Cloud Storage compared with Physical Storage Devices (Storing Locally)?

Answer 30

- The cloud has greater storage capacity than other methods. - The data could be sent directly to the cloud from any device. - The data can be accessed from any device and anywhere in the world. - The backups are automatic. - It is easier to add storage capacity (extra storage).

Question 31

What are some disadvantages of Cloud Storage compared with Physical Storage Devices (Storing Locally)?

Answer 31

- The owner of the data loses control over it. - The data cannot be saved, accessed, or downloaded if there is no Internet access. - It may have security issues as personal data might be stored.

Question 32

Define data redundancy.

Answer 32

When the same piece of data is stored in more than one place.

Question 33

Define cloud computing.

Answer 33

- It allows the user to run and manage data, files, services, or applications etc. on a remote server over the Internet.

Question 34

Examples of cloud storage + cloud computing.

Answer 34

Cloud storage: Google Drive, Microsoft OneDrive Cloud Computing: Google Docs, Microsoft 365

Question 35

Define public cloud.

Answer 35

- It is the computing services offered by a 3rd party provider over the public internet. - It is available to anyone with the appropriate equipment

Question 36

Define Private cloud.

Answer 36

- It is the computing services offered either over the internet or a private internal network - ONLY available to selected users and not the general public.

Question 37

Define Hybrid cloud.

Answer 37

- Combination of both public and private clouds - It stores some data in the private cloud, and the less sensitive data is accessed from a public cloud storage provider.

Question 38

3 benefits + 3 drawbacks of Cloud computing.

Answer 38

BENEFITS: - It allows documents to be easily shared. - It can be accessed from anywhere with Internet access. - The user does not need to perform backups. DRAWBACKS: - It cannot be accessed if there is no Internet access. - It cannot be accessed if the server goes down. - It is reliant on someone else to back up.