Computer Storage Devices and Power Supplies

Storage components are among the vital parts of a computer system. Internal storage houses the operating system and application files, while external or secondary storage usually houses backups and supplemental data.

Floppy disk drives – or FDDs – are removable disks on which you can save data

A hard disk drive – abbreviated to HDD – is a non-volatile, fixed storage device

In a magnetic HDD, data is stored on the magnetic surface of multiple hard disk platters. Capacities of magnetic HDDs typically range up to 2 TB per single drive, although capacities are always increasing.

In an SSD, data is stored using semiconductors rather than a magnetic surface. Solid state drive – or SSD – capacities are typically smaller than those of conventional hard drives.

IDE describes Advanced Technology Attachment – or ATA – drives that are based on parallel signaling. They are also called Parallel Advanced Technology Attachment – or PATA – drives.

SATA drives are newer than IDE drives and are based on serial bus technology. These drives use a 7-pin connector and a thinner cable, which is typically red but can appear in other colors

SCSI drives, the oldest of these technologies, are falling out of common use in desktop computers, but provide a fast and flexible interface so are popular on servers and high-performance systems. It uses a single shared cable to connect up to 8 or 16 devices, and the cable has several 50- or 68-pin connectors. A SCSI drive uses a host adapter to connect multiple devices. The host needs to be configured with a SCSI ID of 7 or 15, depending on the width of the bus. Other attached SCSI devices require a unique ID, and this is configured through jumpers or DIP switches. The computer sends data to any attached device using the unique ID of the device

Some SSDs come in the form of expansion cards that can connect through a PCIe slot. This means they connect through the Northbridge chipset and, as a result, are put on a much faster bus than IDE, SATA, or SCSI drives.

Compact discs – or CDs – are discs read using a 780 nm red laser in a CD-ROM drive. CDs come in forms capable of storing up to either 650 MB or 700 MB of data. CD-ROM drives are rated in multiples of 150 Kbps.

A standard Digital Versatile Disc – or DVD – enables you to store 4.7 GB of data on a disk the physical size of a standard CD. A red laser is used to read the disc, but at a shorter wavelength – 650 nm – than the laser used to read CDs. This accounts for the greater storage capacities of DVDs.

Blu-ray discs, also known as BDs, are new generation optical discs capable of storing up to 25 GB of data on a single layer disc, or up to 50 GB of data on a dual-layer disc. The discs are read using a 405 nm blue laser, which is more precise than the more common red lasers. Blu-ray discs are typically used to store high-definition media.

You can write data to writable optical media such as CD-R and DVD-R only once. In other words, you can write to these media only until discs are full – you can't overwrite existing data on the discs. 52x is a common write speed for CD-R, and 32x is common for CD-RW.

Memory cards are similar to thumb drives in that they are solid-state storage devices. Most commonly, memory cards are used in portable devices such as digital cameras and MP3 players

A hot-swappable or hot-pluggable device can simply be plugged into a port and will be detected by an operating system without requiring that you shut down and reboot the computer.