ICT 0417 - Types and Components of Computer Systems

Objective: Know and understand characteristics of ROM and RAM

This section focuses on understanding the fundamental differences between Read-Only Memory (ROM) and Random-Access Memory (RAM), two crucial components within a computer system. Understanding these differences is essential for comprehending how computers store and access information.

RAM (Random-Access Memory)

RAM is a type of volatile memory. This means that data stored in RAM is lost when the power is turned off.

• Volatile: Data is lost when power is removed.
• Read/Write: Data can be both read from and written to RAM.
• Fast Access: RAM provides very fast access to data, making it ideal for active processes.
• Used for: Storing the operating system, applications, and data that are currently being used.
• Types of RAM: Common types include DRAM (Dynamic RAM) and SRAM (Static RAM). DRAM is more common and cheaper, while SRAM is faster but more expensive.

Characteristic	Description
Volatility	Volatile - data lost when power is off
Read/Write	Both read and write operations are possible
Access Speed	Very fast
Typical Use	Operating system, applications, active data

ROM (Read-Only Memory)

ROM is a type of non-volatile memory. This means that data stored in ROM is retained even when the power is turned off.

• Non-Volatile: Data is retained even when power is removed.
• Read-Only (mostly): Data is typically written to ROM during manufacturing and cannot be easily changed by the user. Some types of ROM can be reprogrammed, but this is a more complex process.
• Slower Access: Access speed is generally slower than RAM.
• Used for: Storing firmware (essential instructions for the computer to start), BIOS (Basic Input/Output System), and other permanent data.
• Types of ROM: Common types include PROM (Programmable Read-Only Memory), EPROM (Erasable Programmable Read-Only Memory), and EEPROM (Electrically Erasable Programmable Read-Only Memory).

Characteristic	Description
Volatility	Non-volatile - data retained when power is off
Read/Write	Primarily read-only; some types can be reprogrammed
Access Speed	Slower than RAM
Typical Use	Firmware, BIOS, permanent data

Key Differences Summarized

The following table summarizes the key differences between RAM and ROM:

Feature	RAM	ROM
Volatility	Volatile	Non-Volatile
Read/Write	Read and Write	Read Only (mostly)
Speed	Fast	Slow
Cost	Relatively expensive	Relatively inexpensive

Understanding the characteristics of RAM and ROM is fundamental to understanding how a computer operates. RAM provides the computer with the working memory it needs to run programs, while ROM provides the essential instructions for the computer to start and function.