Hard disk drives are connected to the motherboard over one of a number of bus types. Most common options include parallel ATA (PATA, a.k.a. IDE), Serial ATA (SATA) and SCSI. Other possible types are, for example, Serial Attached SCSI (SAS) and Fibre Channel. Additionally, there is a number of variants of the mentioned bus types, which differ from each other by bandwidth and transfer speed.

Hard disks have an internal buffer (or cache) that functions as an intermediate repository for data being transferred between the hard disk and the PC. In hard disks, the buffer is used to hold the results of recent reads from the disk, and also to hold information that is likely to be requested in the near future. The buffer reduces the need to physically access the drive and therefore improves the performance of any hard drive.

SMART is short for Self-Monitoring, Analysis, and Reporting Technology, and is a monitoring system for computer hard disks to detect and report on different indicators of reliability, in the hope of anticipating failures.

The seek time (or random access time) measures the amount of time required for the read/write heads to move between tracks over the surfaces of the platters. Seek time is normally measured as average seek time from one random track to any other and is expressed in milliseconds (msec or ms). It is one of the most important performance measures for hard disks.

The write time (or write seek time) measures the amount of time required for the write heads to move between tracks over the surfaces of the platters. It is normally measured as average write seek time from one random track to any other and is expressed in milliseconds (msec or ms).

The speed at which the platters turn, expressed as rotations per minute (rpm for short).The faster a drive rotates, the higher its transfer rate. The downside of faster rotation is the possibility of overheating and noise.

The length of time that passes between the moment when the disk finds the track and the moment it finds the data.