2024-12-23

GB

Gigabyte to Terabytes

DATARECOVERYUNION.COM02 mins

For fun, here is a comparison of some old storage media with something in our data recovery lab right now.

Gigabyte-to-Terabytes

On the left is an IBM 3380 ‘direct storage access device’ circa 1980. Capacity: 1 GB. On the right, a RAID recovery on one of our lab workbenches, set up in a couple of storage cases.
Capacity: 48 TB.

The cases and the old IBM device are about the same size… ~30cm across, but of course 30 years difference.

Gigabyte:

The gigabyte is a multiple of the unit byte fordigital information storage. The prefix giga means 109 in the International System of Units (SI), therefore 1 gigabyte is1000000000 bytes. The unit symbol for the gigabyte is GB or Gbyte, but not Gb (lower case b) which is typically used for the gigabit.

Terabytes:

The terabyte is a multiple of the unit byte digital information. The prefix tera means 1012 in the International System of Units (SI), and therefore 1 terabyte is 1000000000000 bytes, or 1trillion (short scale) bytes, or 1000 gigabytes. 1 terabyte in binary prefixes is 0.9095 tebibytes, or 931.32 gibibytes. The unit symbol for the terabyte is TB or TByte, but not Tb(lower case b) which refers to terabit.

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How does HDD store data?

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How does HDD store data?Hard disk drives store data on one or more metal oxide platters. These platters spin at a rate of 3600-10,000 revolutions/minute, hold magnetic charges. A read-write head attached to an actuator arm actually floats on a cushion of air, 1-2 micro-inches (one millionth of an inch) above the surface of the platters. Data flows to and from these heads via electrical connections. Any force alters this process may cause data loss.

Ten years ago hard drives stored 40 Megabytes (MB) of data. Today’s hard drives store data up to 2000 gigabytes (GB) on a smaller surface. Increasing storage capacities amplify the impact of data loss. As more and more data is stored in smaller and denser areas, mechanical precision becomes crucial.

As a part of this advancing technology, the drive tolerance (distance between the read/write head and the platter where data is stored) is steadily decreasing. A slight nudge, an unstable power surge or a dust introduced into the drive may cause the head to touch the platter, resulting in a head crash, PCB burnt, bad sectors, etc. In some situations, the data residing in the area touched by the head may be permanently destroyed.

The current tolerance drives is 1-2 micro-inches (millionths of an inch). Comparatively, a speck of dust is 4-8 micro-inches and human hair 10 micro-inches. These sizes contaminants can cause serious data damage.

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Glossary of Western Digital Hard Disk Drive (Letter G)

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GB
Gigabyte. WD defines a gigabyte as 1,000,000,000 (one billion) bytes or 1000 (one thousand) megabytes.

GMR
Giant magnetoresistive. An advanced form of head technology.

GPL
General Public License. Free software license which grants recipients rights to modify and redistribute the software which would otherwise be prohibited by copyright law.

GPS
Global positioning system. Provides specially coded satellite signals which can be processed in a GPS receiver to compute position, speed, and time.

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