Hard Drives

RAID 6

(striped disks with dual parity) combines four or more disks in a way that protects data against loss of any two disks.

SSD Drive sizes

1.8-inch, 2.5-inch, 3.5-inch

RAID 0 Minimum Disks

2

RAID 1 Minimum Disks

2

Raid 5 Minimum Disks

3

Raid 0+1 Minimum Disks

4

Raid 10 Minimum Disks

4

Raid 6 Minimum Disks

5

Common Hard Drive Speeds

5400, 7200, 10000, 15000 RPMs

RAID 0

A RAID array in which every time data is written to disk, a portion (block) is written to each disk in turn, creating a "stripe" of data across the member disks. RAID 0 uses the total disk space in the array for storage, without protecting the data from drive failure. (2)

Serial ATA

A drive interface for EIDE drives that transfers data serially at speeds between 150 MBps and 300 MBps and 6 Gbps, depending on the version of the standard.

RAID 10

A fault-tolerant type of RAID that combines the mirroring of RAID 1 in two or more independent mirrored sets that are striped together with RAID 0 to produce larger volumes than any single mirrored set could provide.

Autodetection

A feature of system BIOS and hard drives that automatically identifies and configures a new drive in BIOS setup.

Hard disk drive

A magnetic storage device that stores data on metal platters that have a coating that holds data in the form of changes to small magnetic particles in the coating. Also called HDD.

Software RAID

A method of implementing RAID that uses software to implement and control RAID techniques over virtually any type of hard disk(s). RAID software may be a third-party package or utilities that come with an operating system NOS.

Disk Striping

A type of RAID level 0 in which an individual file is divided into sections and saved concurrently on multiple disks.

ATA-3

Added new features called Self-Monitoring Analysis and Reporting Technology (S.M.A.R.T)

ATAPI-7

Allows up to 144 petabytes

RAID 1

Also called mirroring, this RAID array type provides fault tolerance because all the data is written identically to the two drives in the mirrored set.

RAID 5

Combines disk striping across multiple disks with parity for data redundancy. Parity information is stored on each disk. If a single disk fails, its data can be recovered. Provides fault tolerance for a single disk failure. Provides an increase in performance for read operations. Write operations are slower with RAID 5 because of the time required to compute and write the parity information.

Magnetic Hard Drives

Contain one or more metal hard disks or platters that are coated with a magnetizable substance.

eSATA

External Serial advanced technology attachment - an external interface for SATA. Transfer rate of 3Gbps

RAID 1 Duplexing

Faster and safer, drives are assigned the same letter

mSATA

Introduced in the SATA 3.1 standard, it includes support for SSDs and a scaled-down form factor for mobile devices. Also called MiniSATA.

Disk Striping with parity

Method for providing fault tolerance by writing data across multiple drives and then including an additional drive, called a parity drive, that stores information to rebuild the data contained on the other drives. Requires at least three physical disks: two for the data and a third for the parity drive. This provides data redundancy at RAID levels 3-5 with different options.

Hardware RAID

One of two ways to implement RaID. Hardware RaID is more reliable and better performing than software RaID, and is implemented using the BIOS on the motherboard or a RaID controller card.

SATA improvements over PATA

Point-to-point connections between the SATA device and the host bus adapter (HBA); Narrower cables; Maximum cable length 1 meter; Hot-swappable; No drive limit; Theoretically 30 times faster than PATA 1.5Gbps, 3Gbps, and 6Gbps

Drive recognition by a PC requires

Power Proper connection CMOS setup recognition

Disk Mirroring

Process by which data is written simultaneously to two or more disk drives. Read and write speed is decreased but redundancy in case of catastrophe is increased.

Solid-State Drive

Storage device that typically uses flash memory or store data, instructions, and information

Spindle Speed

The rate at which a disk platter spins in a hard drive system, measured in revolutions per minute (rpm).

SATA 3.2

Ties capable drives directly into the PCI Express bus on motherboards Lack of overhead enhances speed of throughput Requires motherboard with SATAe support to take advantage of superfast speeds

Advanced technology Attachment

Type of hard drive and controller designed to replace the earlier ST506 and ESDI drives without requiring replacement of the AT BIOS-hence, AT attachment. These drives are more popularly known as IDE drives.The ATA/33 standard has drive transfer speeds up to 33 MBps; the ATA/6 up to 66 MBps; the ATA/100 up to 100 MBps; and the ATA/133 up to 133 MBps.

Hybrid Hard Drive

Uses both solid state and magnetic technologies

Boot Order

a list of bootable devices; specifies that the order the system should attempt to boot from

RAID 0+1

a striped data set which is then mirrored; requires a minimum of four drives: two mirrored drives to replicate the data on the RAID 0 array

hot-swapping

allows you to connect and disconnect a device while the system is running.

Parallel ATA

also called the IDE (Integrated Drive Electronics) standard, is older and slower than SATA. PATA allows for one or two IDE connectors on a MB, each using a 40-pin data cable

Native Command Queuing

disk-optimization feature that enables faster read/write speeds

Non-Volatile Memory Express

specification supports communication connection directly through a PCIe bus lane. Reduces latency

Disk Duplexing

technology that uses two controllers and two disks to keep identical copies of data to prevent the loss of data if one disk fails

Advanced Host Controller Interface

unlocks the advanced features of SATA such as hot-swapping and native command queuing.