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What Advantages Do Tape Drives Have Over Hard Disk Drives?
- By James Walsh
- Published 04/1/2008
- Hardware
- Unrated
The device the computers need for storing data should offer non-volatile storage, be capable of giving trouble-free service for thousands of hours, be reasonably rugged and reliable, offer a very high capacity and, most of all, be able to access data randomly. There is only one storage device that fits the bill – hard disks. Fifty years after their invention, they are still ruling the roost as the primary storage devices for desktops, laptops and servers.
However, while hard disks are great as primary storage devices, they cannot be used for archival storage of data due to their high cost. This is where tape drives come in. Hard drives and tape drives have been two prominent devices for data storage purposes for many decades now. Both have many differences and similarities.
Tape Drives
Tape drives have two parts – the drive and the cassette. The latter is a small case made of tough plastic inside which exists a very long length of narrow plastic tape wound around a couple of spools. Each cassette can have a capacity of 20 GB or above. Typically, a drive is used with a set of dozens of cassettes which combined offer a huge storage capacity to the user.
Once the cassette is inserted into the tape drive, a motor starts spinning the tape from one spool to another at the rate of about two inches per second. The tape moves forward or backward brushing past a stationary read / write head. The latter has an electromagnet that changes the orientation of the magnetic particles on the tape to record or delete data.
Hard Drives
Hard drives come in the shape of a small rectangular aluminium box inside which are located a number of platters arranged as a vertical tower. The platters, made of glass or metal, sit on a spindle motor that spins them at an incredible speed of 5,400 or 7,200 RPM. There is a separate read / write head for each platter. As the platters move, the head hovers above them and transfers data to the CPU. Hard drives have huge capacities that can go up to a whopping 500 GB. They offer random access, that is, the head can pick up any data file located anywhere on the platter surface instantly without any delay.
Similarities
Hard disks
and tape drives have many similarities. Both use magnetic properties to store data. The platters of a disk as well as the tape of a cassette are coated with a thin layer of magnetic paint. This forms the actual data recording surface. In both cases, the surface is accessed and modified by a head that contains an electro magnet. Both the devices are prone to data damage due to strong magnetic fields. Both have been around for decades and are considered quite cheap and reliable storage media. They have huge capacities that are much higher compared to other popular storage devices such as USB drives and optical disks (compact disks and digital video disks).
Differences
The hard disk, true to its name, uses hard metal or glass platters coated with magnetic paint as the data-recording media. The tape drives, on the other hand, use a thin and narrow ream of plastic tape for the purpose. While a hard disk may lose data due to a head crash, the biggest worry in a tape drive is that the tape may get stuck in the head and snap.
A hard disk offers random data access to the computer. This is because the head as well as the platter both are mobile. This enables very fast data access speeds. A tape drive in contrast can only offer sequential data access. The read / write head is stationary and cannot move. The entire tape has to move back and forth in front of it until the desired file is found. This can take a lot of time. In tape drives, the recording media makes physical contact with the head, unlike hard disks where the head floats over the platters.
Tape drives make excellent media for archival and long-term storage of information because they afford very low cost per MB of data stored. The hard disks are devices which are meant for use as primary storage media for computers because of their random access but high cost. They are not practical for storing data for a number of years. The hard disks have a competitor on the horizon – high-capacity USB drives – which offer much better performance while hardly using any power. Tape drives though have no competition currently for low-cost, high-capacity archival data storage.
James Walsh is a freelance writer and copy editor. If you are concerned about data loss and would like more information on Data Recovery see
http://www.fields-data-recovery.co.uk
However, while hard disks are great as primary storage devices, they cannot be used for archival storage of data due to their high cost. This is where tape drives come in. Hard drives and tape drives have been two prominent devices for data storage purposes for many decades now. Both have many differences and similarities.
Tape Drives
Tape drives have two parts – the drive and the cassette. The latter is a small case made of tough plastic inside which exists a very long length of narrow plastic tape wound around a couple of spools. Each cassette can have a capacity of 20 GB or above. Typically, a drive is used with a set of dozens of cassettes which combined offer a huge storage capacity to the user.
Once the cassette is inserted into the tape drive, a motor starts spinning the tape from one spool to another at the rate of about two inches per second. The tape moves forward or backward brushing past a stationary read / write head. The latter has an electromagnet that changes the orientation of the magnetic particles on the tape to record or delete data.
Hard Drives
Hard drives come in the shape of a small rectangular aluminium box inside which are located a number of platters arranged as a vertical tower. The platters, made of glass or metal, sit on a spindle motor that spins them at an incredible speed of 5,400 or 7,200 RPM. There is a separate read / write head for each platter. As the platters move, the head hovers above them and transfers data to the CPU. Hard drives have huge capacities that can go up to a whopping 500 GB. They offer random access, that is, the head can pick up any data file located anywhere on the platter surface instantly without any delay.
Similarities
Hard disks
Differences
The hard disk, true to its name, uses hard metal or glass platters coated with magnetic paint as the data-recording media. The tape drives, on the other hand, use a thin and narrow ream of plastic tape for the purpose. While a hard disk may lose data due to a head crash, the biggest worry in a tape drive is that the tape may get stuck in the head and snap.
A hard disk offers random data access to the computer. This is because the head as well as the platter both are mobile. This enables very fast data access speeds. A tape drive in contrast can only offer sequential data access. The read / write head is stationary and cannot move. The entire tape has to move back and forth in front of it until the desired file is found. This can take a lot of time. In tape drives, the recording media makes physical contact with the head, unlike hard disks where the head floats over the platters.
Tape drives make excellent media for archival and long-term storage of information because they afford very low cost per MB of data stored. The hard disks are devices which are meant for use as primary storage media for computers because of their random access but high cost. They are not practical for storing data for a number of years. The hard disks have a competitor on the horizon – high-capacity USB drives – which offer much better performance while hardly using any power. Tape drives though have no competition currently for low-cost, high-capacity archival data storage.
James Walsh is a freelance writer and copy editor. If you are concerned about data loss and would like more information on Data Recovery see
http://www.fields-data-recovery.co.uk