Primary Memory (Main Memory):

RAM (Random Access Memory): RAM is volatile memory used for temporarily storing data that the CPU is currently working on. It allows for fast read and write operations but loses data when the computer is powered off. Characteristics include speed, volatility, and high capacity (measured in GBs).

ROM (Read-Only Memory): ROM is non-volatile memory that stores firmware or software instructions that are permanently written during manufacturing. It retains data even when the power is turned off. Characteristics include non-volatility and read-only access.

Secondary Memory (Storage Memory):

Hard Disk Drive (HDD): HDDs are non-volatile, magnetic storage devices that offer high-capacity storage at a relatively lower cost. They are slower than SSDs but are commonly used for long-term data storage.

Solid-State Drive (SSD): SSDs use NAND flash memory for non-volatile data storage. They are faster, more energy-efficient, and durable compared to HDDs. SSDs are commonly used as primary storage in modern computers.

Optical Drives: These include CD, DVD, and Blu-ray drives, used for reading and writing optical discs. They are slower for data access but are still used for archiving and media distribution.

USB Drives (Flash Drives): These are portable and non-volatile storage devices that use NAND flash memory. They are commonly used for data transfer and backup due to their small size and convenience.

Memory Cards: These small, portable storage devices are commonly used in cameras, smartphones, and other portable devices. They use NAND flash memory and come in various formats like SD, microSD, and CompactFlash.

Tertiary Memory:

• Magnetic Tapes: Although less common today, magnetic tapes were historically used for long-term archival storage due to their high capacity. They are sequential access devices and not suitable for fast retrieval.

Cache Memory:

• L1, L2, and L3 Cache: These are small, high-speed memory units located closer to the CPU cores. They store frequently accessed data and instructions to reduce CPU access times to main memory (RAM).

Virtual Memory:

• Virtual memory is a memory management technique that uses a portion of the secondary storage (usually HDD or SSD) to simulate additional RAM. It allows computers to run larger applications and processes that require more memory than physically available.

Registers:

• Registers are the smallest, fastest, and most expensive type of memory, located within the CPU. They store data and instructions directly used by the CPU during its operations.