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Memory and storageMain memory is a key component of a computer system that works in tandem with secondary storage. This allows the system to run instructions, while secondary storage retains data. Cloud storage allows data to be stored at a remote location online.
Computers use main
memory such as random access memory
(RAM) and
cache to hold
data that is being processed. However, this type of memory is
volatile - it loses its contents when the computer is switched off.
General purpose computers, such as personal computers and tablets, need to be able to store
programs and data for later use. Secondary storage is needed to keep
programs and data long term. Secondary storage is non-volatile, long-term storage. Without secondary storage all programs and data would be lost the moment the computer is switched off. There are three main types of secondary storage in a computer system:
However, not all computers require secondary storage. Embedded computers, such as those found in a washing machine or central heating system, do not need to store data when the power is turned off. The instructions needed to run them are stored in read-only memory (ROM) and any user data is held in RAM. Solid stateSolid state storage is a special type of storage made from silicon microchips. It can be written to and overwritten like RAM. However, unlike RAM, it is non-volatile, which means that when the computer's power is switched off, solid state storage will retain its contents. Solid state is also used as external secondary storage, for example in USB memory sticks and solid state drives. One of the major benefits of solid state storage is that is has no moving parts. Because of this, it is more portable, and produces less heat compared to traditional magnetic storage devices. Less heat means that components last longer. Solid state storage has no moving parts making it more portable and durable. Solid state storage is also faster than traditional hard disk drives because the data is stored electrically in silicon chips called cells. Within the cells, the binary data is stored by holding an electrical current in a transistor with an on / off mode. Unlike RAM which uses a similar technique, solid state storage retains this even when the power is switched off by using a technology known as flash memory. Solid state is an ideal storage medium for many modern devices such as tablets, smartphones and digital cameras. Magnetic devicesMagnetic devices such as hard disk drives use magnetic fields to magnetise tiny individual sections of a metal spinning disk. Each tiny section represents one bit. A magnetised section represents a binary '1' and a demagnetised section represents a binary '0'. These sections are so tiny that disks can contain terabytes (TB) of data. As the disk is spinning, a read/write head moves across its surface. To write data, the head magnetises or demagnetises a section of the disk that is spinning under it. To read data, the head makes a note of whether the section is magnetised or not. Magnetic devices are fairly cheap, high in capacity and durable. However, they are susceptible to damage if dropped. They are also vulnerable to magnetic fields - a strong magnet might possibly erase the data the device holds. Optical devicesOptical devices use a laser to scan the surface of a spinning disc made from metal and plastic. The disc surface is divided into tracks, with each track containing many flat areas and hollows. The flat areas are known as lands and the hollows as pits. When the laser shines on the disc surface, lands reflect the light back, whereas pits scatter the laser beam. A sensor looks for the reflected light. Reflected light - land - represents a binary '1', and no reflection - pits - represents a binary '0'. There are different types of optical media:
GCSE Subjects
Which of the following is referred to as secondary storage?Secondary storage might include hard disk drives (HDDs), solid-state drives (SSDs), optical disks, USB flash drives, floppy disks or other devices.
Which of the following is not an example of secondary storage?R.A.M is not an example of a secondary storage device.
Which of the following are examples of secondary storage quizlet?The term secondary storage is sometimes used to describe devices that can store data permanently, such as a hard drive, flash drive, compact disc, DVD, or external hard drive. This is because the computer will look for data on one of these devices if the data is not in RAM.
What is not a mass storage device?The correct answer is Modem.
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