GCSE COMPUTER SCIENCE CIE | TOPIC 3 STORAGE

3.3.1 & 3.3.2 | PRIMARY & SECONDARY STORAGE

Topics from the Cambridge IGCSE (9-1) Computer Science 0984 syllabus 2023 - 2025.

OBJECTIVES
3.3.1 Understand what is meant by primary storage
• Primary storage is directly accessed by the CPU
– random access memory (RAM)
– read only memory (ROM)
• Including why a computer needs both RAM and ROM, and the difference between them

3.3.2 Understand what is meant by secondary storage
Secondary storage is not directly accessed by the CPU and is necessary for more permanent storage of data

ALSO IN THIS TOPIC
3.1.1 COMPUTER ARCHITECTURE
3.1.2 COMPUTER ARCHITECTURE
3.1.3 COMPUTER ARCHITECTURE
3.1.4 COMPUTER ARCHITECTURE
3.1.5 COMPUTER ARCHITECTURE
3.2.1 INPUT AND OUTPUT DEVICES
3.2.2 INPUT AND OUTPUT DEVICES
3.2.3 INPUT AND OUTPUT DEVICES
YOU ARE HERE | 3.3 DATA STORAGE
3.4 NETWORK HARDWARE
REVISION CARDS
TOPIC 3 KEY TERMINOLOGY
TOPIC 3 ANSWERS
TOPIC 3 TEACHER RESOURCES
TOPIC 1 TEACHER RESOURCES (CIE)

PRIMARY STORAGE

Primary storage, also known as main memory, is a type of computer memory that is directly accessible by the CPU (Central Processing Unit). It is used to temporarily store data and instructions that the CPU is currently working on, and provides fast access to frequently used data.

Primary storage typically includes Random Access Memory (RAM) and read-only memory (ROM), which is non-volatile and The size and speed of primary storage can have a significant impact on the performance of a computer system.

ROM

ROM (Read-Only Memory) is a type of computer memory that stores data that cannot be changed or overwritten. As the name suggests, data stored in ROM can only be read and accessed, not written to or modified.

ROM is non-volatile, meaning it retains its contents even when the computer is turned off. It is used to store important data that must be preserved, such as firmware, basic input/output system (BIOS) code, and other critical system information.

There are several types of ROM, including Mask ROM, Programmable ROM (PROM), Erasable Programmable ROM (EPROM), and Electrically Erasable Programmable ROM (EEPROM). PROM, EPROM, and EEPROM can be programmed and rewritten using special equipment, but this is not possible with Mask ROM.

Overall, ROM plays a critical role in the proper functioning of a computer system, providing permanent storage of essential data and code that is necessary for the system to operate.

RAM

RAM (Random Access Memory) is a type of computer memory that temporarily stores data that the CPU (Central Processing Unit) is actively using. RAM is volatile memory, meaning that its contents are lost when the computer is turned off or restarted.

RAM provides the CPU with quick access to data and instructions that are frequently accessed, improving the overall performance of the computer. When an application is launched or a file is opened, the data is loaded from the hard disk or other storage device into RAM, where it can be accessed much more quickly by the CPU.

The amount of RAM in a computer can have a significant impact on its performance, particularly when running memory-intensive applications such as video editing or gaming software. More RAM allows for more applications to be opened and run simultaneously without slowing down the computer.

There are different types of RAM, including Dynamic RAM (DRAM) and Static RAM (SRAM), with DRAM being the most commonly used type in personal computers. RAM can be upgraded or replaced to increase the amount of available memory in a computer system.

RAM VS ROM

A computer needs both RAM and ROM because they serve different purposes in the operation of the system.

ROM (Read-Only Memory) is used to store permanent data and instructions that are required for the computer to start up and operate. This includes firmware, BIOS (Basic Input/Output System) code, and other system information that is essential for the proper functioning of the computer. Because the data stored in ROM cannot be modified, it ensures that this critical information is preserved even when the computer is turned off or restarted.

RAM (Random Access Memory), on the other hand, is used to temporarily store data that the CPU (Central Processing Unit) is actively using. This includes data and instructions for applications that are currently running, as well as data that has been recently accessed and is likely to be needed again in the near future. Because RAM is much faster to access than other types of storage, it allows the CPU to retrieve and process data more quickly, which improves the overall performance of the computer.

ROM provides the computer with essential system information that is required for it to start up and operate, while RAM provides the CPU with quick access to frequently used data and instructions, improving the speed and efficiency of the system.

RAM (Random Access Memory) and ROM (Read-Only Memory) are both types of computer memory, but they have several key differences:

Volatility: RAM is volatile memory, meaning that its contents are lost when the computer is turned off or restarted. ROM, on the other hand, is non-volatile memory that retains its contents even when the computer is powered off.
Read/Write Access: RAM is read-write memory, meaning that data can be both read and written to it. ROM is read-only memory, meaning that data can be read from it but not written to it.
Purpose: RAM is used to temporarily store data and instructions that the CPU (Central Processing Unit) is actively using, providing quick access to frequently accessed information. ROM is used to store permanent data and instructions that are required for the computer to start up and operate, providing essential system information.
Types: There are several types of RAM, including DRAM (Dynamic RAM) and SRAM (Static RAM). There are also different types of ROM, including Mask ROM, PROM (Programmable ROM), EPROM (Erasable Programmable ROM), and EEPROM (Electrically Erasable Programmable ROM).
Upgradability: RAM can be upgraded or replaced to increase the amount of available memory in a computer system. ROM is generally not upgradable, as its contents are fixed at the time of manufacture.

Overall, RAM and ROM serve different purposes in the operation of a computer system, with RAM providing temporary storage of frequently accessed data and instructions, and ROM providing permanent storage of essential system information.

SECONDARY STORAGE

Secondary storage, also known as external or auxiliary storage, refers to a type of computer storage that is used for long-term data storage. Secondary storage devices are used to store data and programs that are not currently being used or accessed by the computer's CPU (Central Processing Unit).

Unlike primary storage, which provides fast access to frequently used data, secondary storage devices typically have slower access speeds but offer much larger storage capacity. This makes them ideal for storing large files such as videos, photos, and documents, as well as backups of important data.

Examples of secondary storage devices include:

Hard disk drives (HDD)
Solid-state drives (SSD)
Optical discs (CD, DVD, Blu-ray)
USB flash drives
Memory cards (SD, microSD)
Magnetic tapes
External hard drives
Network-attached storage (NAS) devices
Cloud storage services.

Secondary storage is an essential component of modern computing, providing a reliable and cost-effective way to store large amounts of data for long periods of time. There are three main types of secondary storage.

Magnetic Storage: Magnetic storage is a type of storage technology that uses magnetic fields to store data on a disk or tape. The most common example of magnetic storage is the hard disk drive (HDD), which uses spinning disks coated with magnetic material to store data. Magnetic storage is relatively inexpensive and has a large storage capacity, but is slower and more susceptible to physical damage compared to other forms of storage.
Optical Storage: Optical storage is a type of storage technology that uses lasers to read and write data to and from a disk. The most common examples of optical storage are compact disks (CDs) and digital versatile disks (DVDs). Optical storage has the advantage of being relatively inexpensive and having a large storage capacity, but is limited in its ability to store large amounts of data compared to other forms of storage.
Solid-State (Flash Memory) Storage: Solid-state storage, also known as flash memory, is a type of storage technology that uses arrays of transistors to store data. Unlike magnetic and optical storage, solid-state storage has no moving parts, making it faster, more reliable, and less susceptible to physical damage. The most common examples of solid-state storage are solid-state drives (SSDs) and USB flash drives. Solid-state storage is more expensive than magnetic and optical storage, but has a much faster access time and a longer lifespan.

CPU ACCESS

Secondary storage is not directly accessed by the CPU (Central Processing Unit) and is necessary for more permanent storage of data because of the way it is designed and used.

Secondary storage devices, such as hard disk drives (HDD) and solid-state drives (SSD), are typically connected to the computer through a data bus or controller that manages the flow of data between the CPU and the storage device. This means that data stored in secondary storage is not directly accessible by the CPU in the same way that data stored in primary storage, such as RAM, is.

Because secondary storage devices have larger storage capacity than primary storage, they are ideal for storing large files and applications that are not currently being used by the CPU. Secondary storage is also non-volatile, meaning that it retains its contents even when the computer is turned off, making it ideal for long-term storage of data and programs.

By using secondary storage, users can store large amounts of data and applications without having to constantly add or replace hardware. This allows for a more flexible and cost-effective approach to data storage and management, as well as improved system performance by freeing up primary storage for more frequently accessed data.

1: What is the difference between RAM and ROM?
a. ROM is volatile and RAM is non-volatile.
b. RAM is used for long-term data storage, and ROM is used for temporary storage.
c. RAM is read-write memory, and ROM is read-only memory.
d. ROM is upgradable, and RAM is not.

2: Which of the following is a secondary storage device?
a. RAM
b. SSD
c. Cache memory
d. CPU

3: Which type of memory is used to temporarily store data and instructions that the CPU is actively using?
a. Secondary storage
b. ROM
c. RAM
d. Cache memory

4: Which of the following is an example of an optical storage device?
a. Magnetic tape
b. USB flash drive
c. Memory card
d. CD

5: Which of the following is true about primary storage?
a. It is used for long-term data storage.
b. It is non-volatile.
c. It provides fast access to frequently used data.
d. It has larger storage capacity than secondary storage.

6: Which type of storage device is most suitable for storing large files such as videos and photos?
a. RAM
b. SSD
c. Cloud storage
d. Hard disk drive

7: Which of the following best describes cloud storage?
A) A physical hard drive located in your computer where data is stored.
B) A type of data storage where your data is stored on servers located in the cloud, and can be accessed from anywhere via the internet.
C) A type of data storage where your data is stored in physical servers located in your house.
D) A type of data storage where your data is kept in a physical box, and transported to a storage facility.

8: Which type of memory is used to store permanent data and instructions that are required for the computer to start up and operate?
a. RAM
b. Cache memory
c. Secondary storage
d. ROM

9: Which type of storage device is used to provide backup and recovery of data in case of a system failure?
a. Hard disk drive
b. Memory card
c. Tape drive
d. Cloud storage

10: What is the primary advantage of using secondary storage in a computer system?
a. It provides fast access to frequently used data.
b. It is directly accessible by the CPU.
c. It is volatile and retains its contents even when the computer is turned off.
d. It offers larger storage capacity for long-term data storage.

ALSO IN THIS TOPIC

3.1.1 COMPUTER ARCHITECTURE | The role of the CPU
3.1.2 COMPUTER ARCHITECTURE | Components of the CPU
3.1.3 COMPUTER ARCHITECTURE | Core's, Cache and Clock speed
3.1.4 COMPUTER ARCHITECTURE(CIE) | The Instruction Set
3.1.5 COMPUTER ARCHITECTURE | Embedded Systems
3.2.1 INPUT AND OUTPUT DEVICES | Input Devices
3.2.2 INPUT AND OUTPUT DEVICES | Output Devices
3.2.3 INPUT AND OUTPUT DEVICES | Sensors
3.3 DATA STORAGE | Primary, Secondary, Virtual and Cloud storage
3.4 NETWORK HARDWARE | Networks, Components and Protocols
REVISION CARDS | Flip cards to help test yourself
TOPIC 3 KEY TERMINOLOGY
TOPIC 3 ANSWERS
TOPIC 3 TEACHER RESOURCES