[SYMBOL] [A] [B] [C] [D] [E] [F] [G] [H] [I] [J] [K] [L] [M] [N] [O] [P] [Q] [R] [S] [T] [U] [V] [W] [X] [Y] [Z] half-height drives  hard disk drives (HDDs)  2nd      backing up  [See backups]     choosing/recommended  2nd      drive bay arrangements      external      formatting/partitioning      how they work      installing  2nd          ATA drives          preparing for          SCSI drives      interfaces for          IDE/ATA interface          recommendations for          SCSI interface      mounting methods for      OEM software and      orphaned      removable          recommendations for      spindles      ST506 412      upgrading  hardware      parallel ports and, configuring      serial ports and, installing/configuring  hardware compression  2nd  hat switches  HD (High-Density) drive types  HDA (head/disk assembly)  HDDs  [See hard disk drives] head actuator assembly  head/disk assembly (HDA)  header-pin connectors  headphones  heatsink/fan units     caution with          in AMD systems  2nd      installing      for video adapters  HiFD drives (Sony)  high-capacity floppy disk drives      recommendations for  High-Density (HD) drive types  High-Voltage Differential SCSI (HVD SCSI)  Hitachi     displays      DVD drives  hold-up periods  Horizontal Scanning Frequency (HSF)  host adapters      recommendations for  host buses  2nd  [See also front-side bus] HSF (Horizontal Scanning Frequency)  HVD SCSI (High-Voltage Differential SCSI)  hyper-pipelining