| This chart shows the progress of areal density over the last 43 years. The red line is drawn as a best-fit through the blue diamonds which are actual products. Key hard disk head technology developments are indicated. Note that the scale on left is logarithmic, not linear. |
|
| A single hard disk usually consists of several platters. Each platter requires two read/write heads, one for each side. Each platter has the same number of tracks, and a track location that cuts across all platters is called a cylinder. All the read/write heads are attached to a single access arm so that they can not move independently. |
|
| Each track is divided into sectors. High speed disks have an access time of 28 milliseconds or less, and low-speed disks run 65 milliseconds or more. The higher speed disks also transfer their data faster than the slower speed units. |
|
A hard disk can store anywhere from few gigabytes to several terabytes such as Seagate’s 5 TB Barracuda desktop hard drive, whereas most floppies have a maximum storage capacity of several hundred megabytes.
|
“Mockingbirds don’t do one thing but make music for us to enjoy. They don’t eat up people’s gardens, don’t nest in corncribs, they don’t do one thing but sing their hearts out for us. That’s why it’s a sin to kill a mockingbird.” ― Harper Lee, To Kill a Mockingbird |