Hard Drive

The hard drive is the computer hardware device that stores the operating system, program files and user data in a computer system. They come in various capacities, with a maximum commercially available size of 2000 Gigabytes.

Hard Drive Technologies

• Hard Disk Interfaces
  • IDE Integrated Drive Electronics/PATA Parallel Advanced Technology Attachment
  • SATA Serial Advanced Technology Attachment
  • SAS Serial Attached SCSCI
  • SCSI Small Computer System Interface
• Hard Drive Technologies
  • NCQ Native Command Queueing
  • TCQ Tagged Command Queueing
  • RAID Redundant Array of Independent Disks

Hard Drive Manufacturer Websites

• Hitachi
• Maxtor
• Samsung
• Seagate
• Western Digital

General Notes on Hard Drives

External Drives

Apart from internal installation of hard drives, drives can also be connected via other methods. The most common used is a USB enclosure. These enclosures use a small controller which connects to a PC or Laptop via a standard USB 2.0 port. Many are backwards compatible to USB 1 speeds however performance will be near useless at USB 1 speeds. Some other connectivity options include FireWire (400 and 800) and eSATA. eSATA connects directly to the internal chipset or controller used within the computer, but USB and FireWire enclosures have a separate controller chipset.

Operating System support under Windows, OS X, and Linux is very good for almost all off the shelf disk enclosures and adaptors. However some features require particular chipsets to work 100% correctly. For example OS X can only use a USB 2.0 external drive as a bootable volume if an Oxford Bridge chipset is used. Most other chips such as Prolific and JMicron are supported but not as bootable volumes. For general backups and external storage these limitations will not affect the majority of people.

Performance of external consumer devices will generally be in this order:

• eSATA
• FW800
• FW400
• USB 2.0

Also see Storage from the OCAU Content Archive.