Read-only memory(ROM pronounced rahm) refers to memory chips storing permanent data and instructions. ROM

Read-only memory(ROM pronounced rahm) refers to memory chips storing permanent data and instructions. ROM chips cannot be modified — hence, the name read-only. Flash memory is a type of nonvolatile memory that can be erased electronically and rewritten. Flash memory chips also store data and programs on many mobile computers and devices, such as smart phones, portable media players etc.

Storage holds data, instructions, and information for future use.(permanently)

Storage holds data, instructions, and information for future use.(permanently) A storage medium(media is the plural) or(secondary storage), is the physical material on which a computer keeps data, instructions, and information. Examples of storage media are hard disks, solid state drives, memory cards, USB flash drives, Express Card modules, optical discs, smart cards, magnetic stripe cards, and microfilm.

A storage device is the computer hardware that records(writes) and/or retrieves(reads) items to and from

A storage device is the computer hardware that records(writes) and/or retrieves(reads) items to and from storage media.

Writing is the process of transferring data, instructions, and information from memory to a storage medium. Reading is the process of transferring these items from a storage medium into memory. When storage devices write data on storage media, they are creating output. Similarly, when storage devices read from storage media, they function as a source of input. For example, a DVD drive (storage device) accepts a DVD (storage media).

Storage capacity

Storage capacity Capacity is the number of bytes (characters) a storage medium can hold. E.g. USB flash drive can store up to 4 GB of data (app. 4 billion bytes) and a typical hard disk has 320 GB (app. 320 billion bytes) .

USB flash drive

USB flash drive A USB flash drive(thumb drive) is a portable storage device that is small and lightweight enough to be transported on a keychain or in a pocket . The average USB flash drive can hold about 4 billion characters. plugs in a USB port on a computer or mobile device. users easily transfer documents, photos, music, and videos from one computer to another.

Hard disk

Hard disk A hard disk provides much greater storage capacity than a USB flash drive. The average hard disk can hold more than 320 billion characters. Hard disks are enclosed in an airtight, sealed case. Although some are portable, most are housed inside the system unit .

Portable hard disks are either external or removable. An external hard disk is a separate, freestanding unit, whereas you insert and remove a removable hard disk from the computer or a device connected to the computer.

Optical disc

Optical disc An optical disc is a flat, round, portable metal disc with a plastic coating. CDs, DVDs, and Blu-ray Discs are three types of optical discs. A CD can hold from 650 million to 1 billion characters. Some DVDs can store two full-length movies or 17 billion characters . Blu-ray Discs can store about 46 hours of standard video, or 100 billion characters.

Memory cards

Memory cards Memory cards as the storage media is used by, some mobile devices such as digital cameras. You can use a card reader/writer (Figure 1-3) to transfer the stored items, such as digital photos, from the memory card to a computer or printer.

Communication device

Communication device A communications device is a hardware component that enables a computer to send (transmit) and receive data, instructions, and information to and from one or more computers or mobile devices. A widely used communications device is a modem.

Communication device

Communication device Communications occur over cables, telephone lines, cellular radio networks, satellites, and other transmission media. Some transmission media, such as satellites and cellular radio networks, are wireless, which means they have no physical lines or wires.

Advantages of using a computer

Advantages of using a computer This include: speed, reliability, consistency, storage, and communications.

Speed: When data, instructions, and information flow along electronic circuits in a computer, they travel at incredibly fast speeds. Many computers process billions or trillions of operations in a single second. Processing involves computing (e.g., adding, subtracting), sorting (e.g., alphabetizing), organizing, displaying images, recording audio, playing music, and showing a movie or video.