Question

What is the difference between a hard drive and a tape drive? Hard drives use magnetic heads and are fast to write data; tape drives write to disks and are fast to retrieve data. Hard drives write to disks and are fast to retrieve data; tape drives use magnetic heads and are fast to write data. Hard drives use magnetic heads and are best for archival data; tape drives write to disks and are used for ongoing backups. Hard drives write to disks and are used for ongoing backups; tape drives use magnetic heads and are best for archival data.

Answer 1

Answer:

A tape drive provides sequential access storage, unlike a hard disk drive, which provides direct access storage. A disk drive can move to any position on the disk in a few milliseconds, but a tape drive must physically wind tape between reels to read any one particular piece of data.

Explanation:

Architecturally tape drives are sequential storage, meaning that if you need to access some data at the end of the tape you needed to seek to the end and retrieve it. This can take seconds or minutes. Disks, OTOH are random access. Some hard drives use rotating media and movable heads , so the seek times are instantaneous , at least compared with tape drives. However, like tapes, there is a big advantage to using a rotating hard drive as sequential storage. It takes time, measured in milliseconds, for a head to move to another track. So traditionally, random access is much slower than sequential access.

SSDs have no internal moving parts so random access occurs in the same time frame as sequential access. Moreover, these drives usually have very high performance. For example, they can saturate a SATA data link, meaning that the SATA connection to the motherboard is now a bottleneck in disk access.

At one time tape drives were very popular. They were a low-cost alternative to using disks as backup. They were especially useful when IBM invented the Winchester “fixed” drive. This meant that the hard drive is fixed within its enclosure like they are today. Prior to this one could remove the drive pack and replace it. This was helpful when upgrading to a new version of the operating system as it was simple to replace the older drive pack should there be a problem.

Tape drives can be used in larger data centers, due to the fact that tape volumes can be removed and replaced so that the actual tape drive can backup many disk sets. Also the tape volumes can be stored off-site or in a fire-proof vault so this is valuable in a data recovery scenario.