What is a tape drive?

What is a tape drive?
A tape drive Like IBM 46C1748
is a device that stores computer data on magnetic tape, especially for backup and archival purposes. Like an ordinary tape recorder, a tape player records data on a loop of flexible celluloid-like material that can be read as well as erased.

Tape drives work either using traditional helical scanning where the record and playback heads touch the tape, or linear tape technology where the heads never touch the tape. Drives can be rewound, where the device issues a rewound command at the end of a session, or not rewound.

Rewind devices are commonly used when a tape needs to be dismounted at the end of a session after batch processing of large amounts of data. Payroll is the classic example of this use. Rewind-less devices are useful for incremental backups to tape and other applications where new files are added to the end of files from the previous session.

Tape drives differ from hard disk drives (HDDs) and solid-state drives (SSDs) in the way data is read from and written to storage media. Tapes store data sequentially, while HDDs and SSDs use spinning platters with fast-moving seek heads, immobile flash memory, or similar technology to transfer data.

Discs are available in many sizes and capacities. They are sold as stand-alone units or stacked in data center racks, creating tape libraries. The tapes themselves are usually housed in sealed cassettes that can be inserted into the drive and activated.

Strengths and limitations of tape drives
There are several benefits to using tape drives, especially for backup and archiving. They include the following:

Ability. Tapes have a large data storage capacity compared to hard drives.
Low cost. They are inexpensive compared to other storage media.
Life expectancy. Tapes stored in the proper environment can last for decades, an important factor for archival storage.
Transportable. Tapes can be easily moved from one location to another and are considered offline storage.
Security. Today's tapes support encryption such as Advanced Encryption Standard-256 and provide different levels of data protection.
Disaster recovery. Tape is often the storage medium of choice for data backup and DR. Storing critical systems and data on tape creates an air gap between systems exposed to cyber attacks by simply removing the tape cassette from the drive.
Some disadvantages of tape technology are:

Sequential storage. Tape drives use a sequential access approach to reading and writing data. This means that they must start at the beginning of the tape and traverse the tape to access specific data or write new data.
Shoe polish. Tape drives spin up fast. When the drive finds the data it needs to transfer, the tape must stop and go back to the point where the data is located. This start, stop, and save action may continue multiple times until the appropriate location is reached. The reader's movement resembles the back-and-forth action of shoe polish. Excessive shoe polish slows controller response time, wears down the belt and drive, and shortens the life of both.
On and off operation. Data to be stored on tape is typically buffered before being transmitted to tape. If the buffers are not full, the tape can be stopped and positioned for the next delivery of data from the buffers. This reduces the overall processing efficiency of the disk.