Secondary memory is a type of computer memory that is not directly accessed by a computer’s central processing unit (CPU) and is generally available as nonvolatile memory. One of the most common forms of this memory is a computer’s hard drive, which is used to store the operating system (OS) and other programs. Other forms of secondary memory include disk drives for compact discs (CDs) or digital versatile discs (DVDs), as well as removable flash memory. In contrast to this, primary memory is computer memory accessed directly by the CPU, usually volatile memory, and tertiary memory refers to systems external to a computer that can be accessed directly through various means.
USB devices use secondary memory.
There are several different types of memory used by computer systems, and secondary memory is one of the most common and important. This type of memory is typically recognized by the way it is used by a computer system and the way data is stored on it. The main characteristic of this type of memory is that it is not accessed directly by the CPU, but through a connection that allows the utilization of the CPU. This type of memory is also generally non-volatile, which means it retains data even without a power supply.
A computer’s hard disk qualifies as secondary memory.
One of the most common types of secondary memory is a computer’s hard drive. This drive is accessed by the CPU via one of several different indirect methods and data remains on the drive even without a power supply. Other disk drives, such as those used with CDs and DVDs, are also types of secondary memory used for other purposes. Easily removable types of memory such as flash drives are also secondary memory and use interfaces such as a universal serial bus (USB) port to be accessed by the CPU.
In addition to secondary memory, many computer systems also use primary memory, tertiary memory, and offline storage. Primary memory is the memory of a computer that is accessed directly by the CPU, i.e. random access memory (RAM) and the memory used to store the basic input/output system (BIOS). Tertiary memory is typically external memory that a computer can directly access through some sort of automated system, such as a bank of hard drives that can be connected to a computer through the use of robotic armor. Offline storage is memory that can be used and accessed remotely, such as servers that can be used through an internet connection for data backup or storage.