Requirements for removable media
storage devices (RMSDs) used with personal computers have changed significantly
since the introduction of the floppy disk in 1971. At one time, desktop
computers depended on floppy disks for all of their storage requirements. Even
with the advent of multigigabyte hard drives, floppy disks and other RMSDs are
still an integral part of most computer systems, providing.
Transport between computers for data files and software
Backup to preserve data from the hard dive
A way to load the operating system software in the event of a hard
failure.
Data
storage devices currently come in a variety of different capacities, access
time, data transfer rate and cost per Gigabyte. The best overall performance
figures are currently achieved using hard disk drives (HDD), which can be
integrated into RAID systems (reliable arrays of inexpensive drives) at costs
of $10 per GByte (1999). Optical disc drives (ODD) and tapes can be configured
in the form of jukeboxes and tape libraries, with cost of a few dollars per
GByte for the removable media. However, the complex mechanical library
mechanism serves to limit data access time to several seconds and affects the
reliability adversely.
Most
information is still stored in non-electronic form, with very slow access and
excessive costs (e.g., text on paper, at a cost of $10 000 per GByte).
Some
RMSD options available today are approaching the performance, capacity, and
cost of hard-disk drives. Considerations for selecting an RMSD include
capacity, speed, convenience, durability, data availability, and
backward-compatibility. Technology options used to read and write data include.
Magnetic formats that use magnetic
particles and magnetic fields.
Optical formats that use laser light
and optical sensors.
Magneto-optical
and magneto-optical hybrids that use a combination of magnetic and optical
properties to increase storage capacity.
The
introduction of the Fluorescent Multi-layer Disc (FMD) smashes the barriers of
existing data storage formats. Depending on the application and the market
requirements, the first generation of 120mm (CD Sized) FMD ROM discs will hold
20 - 100 GigaBytes of pre -recorded data on 12 — 30 data layers with a total
thickness of under 2mm.In comparison, a standard DVD disc holds just 4.7
gigabytes. With C3D’s (Constellation 3D) proprietary parallel reading and
writing technology, data transfer speeds can exceed 1 gigabit per second, again
depending on the application and market need.