Data Storage Overview

The central processing unit (CPU) is made up of two main components: the control unit and the arithmetic logic unit (ALU). The control unit directs and controls other parts of the computer, while the ALU performs arithmetic and logical operations.

Registers are temporary storage locations within the CPU that hold instructions, data, or addresses. They are faster than main memory and are used for storing, accepting, and transferring data.

A bit is the smallest unit of data in a computer, representing either a 0 or a 1. Bit patterns are used to represent information, including numbers, text characters, images, sound, and more.

Boolean operations manipulate true/false values. Common operations include AND, OR, XOR (exclusive or), and NOT.

A gate is an electronic circuit that implements a specific Boolean operation. It's like a small building block used to construct computers. Very large scale integration (VLSI) is a technology that allows for the creation of complex circuits using millions of transistors.

Registers hold data related to the current operation being executed, while memory stores data and programs that are needed in the near future. Auxiliary memory stores data and programs that will be needed later.

Binary notation represents numbers using only the digits 0 and 1, instead of the ten digits (0-9) used in the decimal system.

Main memory, also called primary memory, primary storage, internal memory, or main storage, holds the instructions and data for the program being executed. The contents of main memory are typically lost when the computer is turned off.

A type of secondary storage that uses magnetic disks to store data.

A secondary storage device, typically used for data backup, that uses magnetic tape for storing data.

A type of secondary storage that uses laser technology to store data on a disk.

A disk drive that enables reading and writing data to and from a disk using a read/write head.

A type of secondary storage where a fixed number of adjacent sectors are grouped together as a single unit for efficient data management by the operating system.

A unit of main memory, typically comprising 8 bits, which is equivalent to one byte.

The bit at the left (high-order) end of a memory cell.

The bit at the right (low-order) end of a memory cell.

A unique identifier for a memory cell within the computer's main memory. It is a numerical address.

A type of memory that allows both reading and writing data. It is volatile, losing data when power is turned off.

A type of RAM that is more expensive but faster than DRAM, and does not need constant refreshing.

A type of RAM that is cheaper than SRAM, needs constant refreshing, and is found in most PCs.

A type of memory that allows only reading data and not writing. It stores permanent data that cannot be changed.

A circular portion of the disk surface that passes under the read/write head.

Each track is divided into small arcs called sectors on which information is recorded as a continuous string of bits. Each track is divided into sectors that hold a fixed number of bytes (typically 512 bytes per sector).

The track on each surface that is beneath the read/write head at a given position of the read/write heads. When file is larger than the capacity of a single track, operating system will store it in tracks within the same cylinder.

The time it takes the access arm to get into position over a particular track.

The time it takes to activate a particular head over a particular track on a particular surface.

The time for the desired data to rotate under the head.

A temporary storage area in memory that holds frequently accessed data from the hard drive. This helps reduce disk access time and improves performance.

A type of secondary storage that uses sequential access, meaning information is accessed in order, like a tape recorder. Used for backups and archival purposes. It is relatively inexpensive.

A drive that can only read data from CDs, storing up to 700 MB per disk. This format was commonly used for software distribution.

A drive capable of writing data onto a CD once. The written disk can then be read by both CD-ROM and CD-R drives.

A drive that can erase and re-write data onto a CD multiple times.

A type of non-volatile RAM, found in devices like cell phones and digital cameras, that uses less power and is smaller than a traditional disk drive. It requires a Flash Drive or Secure Digital Memory Card to function.

A unit of data stored in a mass storage system. It's composed of individual fields and keyfields, and can contain logical or physical records.

Storage location that holds data temporarily during data transfer between devices.

A unique sequence of bits assigned to each character, like letters, punctuation marks, or symbols. This allows computers to represent and process text.

A standard that uses 7 bits to represent most symbols in written English text. It's like a basic code for English characters.

A standard that uses 16 bits to represent a wide range of symbols from different languages around the world. It's like a global codebook for characters.

A technique that uses bits to represent a number in base two, where only 0s and 1s are used. It's like a different way of counting.

A problem that occurs when a calculated value exceeds the maximum value a computer can store, just like trying to fit too much juice in a small cup.

A problem that occurs when a value cannot be represented accurately, like rounding off a number to the nearest whole number. Imagine losing some parts of a picture you take.

A technique that uses sampling of the sound wave at regular intervals to convert sound into a series of numeric values. Think of taking snapshots of a sound wave to recreate it.