* Certain areas on the magnetic disk
drive head are allowed to have a wide tolerance of surface roughness.
Layers are composed of magnetic disk
, optical discs in library devices, and shelf storage.
Choose to store your archive data on rewritable magnetic disk
and you may have an equally difficult time demonstrating that it has not been altered.
A drive with removable, high-capacity, magnetic disk
media potentially meets these criteria.
In the first section Saffady compares optical disk and magnetic disk
drives and media, and in the second he compares optical disk and magnetic tape technology.
A set of transactional or database records that need to be readily accessible should be stored on a high-performance magnetic disk
, while other data that is ready to be archived should be stored to a less costly tape cartridge.
Optical, tape and even magnetic disk
storage has a place in the archive equation.
The other product, eFIRST Archive, is an archive system that includes a magnetic disk
, optical jukeboxes and tape and offers web access to archived information using either traditional index keys or by parts of its content.
"The parametric limit for magnetic disk
drive technology is about 16,000 Mbits/|cm.sup.2~, which gives us a lot of room for improvements," says Scranton.
The reference databases can be configured on CD-ROM or on high-performance magnetic disk
Tape is being used to fulfill this important data storage requirement for two reasons: tape capacities have continued to double every 2-3 years and outpace magnetic disk
capacity using compression; and the cost advantage of tape over magnetic disk
solutions is tremendous.
In contrast, information on a magnetic disk
is retrieved bit by bit by spinning the disk.