PRIMARY MEMORY--These are semiconductor memories. SECONDARY MEMORY--These are magnetic and optical memories. PRIMARY MEMORY--They are characterized as volatile random access memories (RAM) or non-volatile memories (ROM).

Primary memory is the memory that is directly accessed by the CPU to store and retrieve information, whereas the secondary memory is not accessible directly by the CPU. Primary memory is accessed using address and data buses by the CPU, while secondary memory is accessed using input/ output channels. Primary memory does not retain data when the power is turned off (volatile) while secondary memory retains data when the power is turned off (non-volatile).

**PRIMARY MEMORY AND SECONDARY MEMORY** PRIMARY MEMORY--These are semiconductor memories. SECONDARY MEMORY--These are magnetic and optical memories. PRIMARY MEMORY--They are characterized as volatile random access memories (RAM) or non-volatile memories (ROM). SECONDARY MEMORY--They are non-volatile PRIMARY MEMORY---They contain program and data that is currently being used by micro processor. SECONDARY MEMORY--These are used to for bulk storage. Thanks

> `Difference between Primary and Secondary Memory` Primary memory is the memory that is directly accessed by the CPU to store and retrieve information, whereas the secondary memory is not accessible directly by the CPU. Primary memory is accessed using address and data buses by the CPU, while secondary memory is accessed using input/ output channels. Primary memory does not retain data when the power is turned off (volatile) while secondary memory retains data when the power is turned off (non-volatile). Furthermore, primary memory is very fast compared to the secondary memory and has a lower access time. But, primary memory devices are more costly compared to secondary memory devices. Due to this reason, usually a computer comprises of a smaller primary memory and a much larger secondary memory.