Which memory is non-volatile?

Computer Hardware refers to the physical components of a computer system. Main components include: CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), Motherboard, Hard Disk/SSD, Power Supply Unit, Monitor, Keyboard, and Mouse. Hardware is a key topic in Computer Awareness for banking and SSC exams.

RAM (Random Access Memory) is volatile memory that temporarily stores data and programs currently in use. Data is lost when power is off. ROM (Read Only Memory) is non-volatile memory that permanently stores the BIOS/firmware. Data is retained without power. RAM is much faster than ROM and determines how many programs can run simultaneously.

CPU (Central Processing Unit) is the brain of the computer. It consists of: ALU (Arithmetic Logic Unit) that performs mathematical and logical operations, Control Unit that directs operations, Registers that are small fast storage units, and Cache Memory that is the fastest memory between CPU and RAM. CPU speed is measured in GHz.

Computer memory hierarchy from fastest to slowest: Registers (inside CPU), Cache Memory (L1, L2, L3), RAM (Primary Memory), HDD/SSD (Secondary Storage), Optical Disks (CD, DVD), Magnetic Tape (slowest, for backup). As speed decreases, storage capacity increases and cost decreases. This hierarchy is important in Computer Awareness sections.

HDD (Hard Disk Drive) uses magnetic platters that spin at 5400-7200 RPM to store data. It is slower (100-150 MB/s) and has moving parts. SSD (Solid State Drive) uses flash memory chips with no moving parts. It is much faster (500-3500 MB/s), more durable, and quieter but more expensive per GB. SSDs are now standard in modern laptops and computers.