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Saturday, March 9, 2013
- The HDD installs in one of the 3-1/2 inch internal drive bays in the PC. It is secured by machine screws.
- Data Transport: IDE (Integrated Drive Electronics) is a 40 pin ribbon cable originally used to carry data to and from the host bus adapters on the motherboard and the hard disk drive. This parallel bus was later renamedPATA (Parallel Advanced Technology Attachment).
Drives with PATA interfaces are powered by a separate 4-pin cable from the power supply which carries +5v, +12v and ground.
Since 2009 SATA (Serial Advanced Technology Attachment) has replaced PATA in consumer and laptop PC's. It is a very fast serial bus and uses only 7 lines for data transport which is huge reduction from the 40 lines PATA requires.
SATA drives use a separate 15 pin connector for power and receive +5v, +3.3v, +12v and ground from the power supply. - Data Storage is maintained magnetically on multiple rigid disks that are stacked up like pancakes. Small arms with magnetic pickups move rapidly back and forth across the top and bottom surface of each disk in the drive. The sensors float just a few microns above the rotating disk surface and can read and write data (ones and zeroes) at very high rates.
- Most commercially available hard drives rotate at 5400 or 7200 RPM (revolutions per minute) which translates to 90 or 120 revolutions per second respectively. The data transfer rate from the drive to the motherboard is 33 Mbytes/second in bursts. Newer drives are capable of higher speeds up to 66 Mbytes/sec. To use this faster drive, the PC must have an ATA/66 interface that is capable of keeping up with it.
- A 40 Gbyte (Gigabyte) drive in 2004 sold for about $100. In 2012 a 1 Tbyte (Terabyte) drive sells for the same or slightly less and has 25 times more storage capacity!
Source: by John Anthony
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