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What are Tape Drives and where are tape drives used ?

Earlier I spoke about Tape Libraries and its usage, today I’ll speak a bit about Tape drives and where they are use.

Tape drive is a data storage device which is used to read and write data that is stored on a magnetic tape. Tape drives are also known as ‘streamers’. Typically, Tape Drives are used for archival storage of data stored on hard drives.

The data capacities on these tape drives ranges from a few megabytes to several gigabytes. Their transfer speeds also vary considerably. Today you can find Fast tape drives in the market which can transfer as much as 20MB per second.

Tape drives come with sequential-access of data, which makes it slower to read/write data. ie..A tape drive spends significant amount of time winding tape between reels to read any piece of data on the drive. The advantage of hard disk drives over tape drives are that they allow random-access to data. ie..the read/write head moves to any random part of disk platters in a jiff. Thus rendering tape drives slow in the average seek time. however, regardless of slow seek time, they can stream data to tape very quickly.

The interfaces used to connect tape drives to a computer are SCSI, IDE, SATA, USB, FireWire to name a few. Tape drives assist autoloaders and tape libraries in loading, unloading and storing multiple tapes to increase their archiving capacity. So i guess its safe to say that tape drives have certain uses and are not outdated in some respects.

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What is ATA (AT Attachment)?

Talking about the performance of computer systems, its been increasing with fast processors, better memory and video cards.

Hard drive was the only component which had been neglected when talked about performance. Lot of work has been done to better the performance, such as developing faster spindle speeds, larger caches, better reliability, and increased data transmission speeds.

ATA (AT Attachment), also called as IDE(Integrated Drive Electronics) connects storage to computer systems.
Computers can use ATA hard drives without a specific controller to support the drive. The motherboard must still support an ATA connection, but a separate card (such as a SCSI card for a SCSI hard drive) is not needed.

Due to its features, it has replaced earlier technologies such as MFM, RLL and ESDI and is currently competing with SCSI.

Parallel ATA Cables:
This cable had 40 wires initially and with the introduction of ATA-5 the wires increased to 80. This is because 40 wires carried signals and the other 40 were grounded for each signal wire, enabling the system to operate at higher speeds with greater reliability.

The Master and slave are the storage devices the ATA bus supports, and to decide and configure the master and slave device we have two methods:

Drive jumpers and cable select.

In Drive jumpers method you decide on the drive positions. The IDE devices must be configured either as master or slave. The settings are mentioned on the drive.

In Cable selector, the master and slave can be determined by knowing which connector on the cable is attached. One of the connector  has pin #28 connected through a cable (master connector), but the other (slave connector) has an open circuit on that pin (no connection).

Many versions of ATA was brought but the latest standard now is ATA-7. This has the UltraDMA mode 6 which includes with data transfer rates 133MBps. Serail ATA was introduced in ATA-7 unlike the previous standards which had parallel ATA.

The difference in the drive cables is the change in Serial ATA. Higher throughput up to 300MB/s for storage systems, Revised power connector, Longer data cables and Support for external drives(eSata) are its other features.