Data Backup Glossary (Letter M)

Magnetic drum
A direct-access, or random-access, storage device. A magnetic drum, also referred to as drum, is a metal cylinder coated with magnetic iron-oxide material on which data and programs can be stored. Magnetic drums were once used as a primary storage device but have since been implemented as auxiliary storage devices.

Magneto-optical (MO) is a type of data storage technology that combines magnetic disk technologies with optical technologies, such as those used in CD-ROMs. Like magnetic disks, MO disks can be read and written to. And like floppy disks, they are removable. However, their storage capacity can be more than 200 megabytes, much greater than magnetic floppies. In terms of data access speed, Mo disks are faster than floppies but not as fast as hard disk drives.

Mass storage
The various techniques and devices for storing large amounts of data. Modern mass storage devices include all types of disk drives and tape drives. Mass storage is distinct from memory, which refers to temporary storage areas within the computer. Unlike main memory, mass storage devices retain data even when the computer is turned off.

Massive array of idle disks
In storage terminology a massive array of idle disks (MAID) is a technology that uses a large group of hard disk drives (hundreds or even thousands), with only those drives that are needed actively spinning at any given time. MAID is a storage system solution that reduces both wear on the drives and also reduces power consumption. Because only specific disks spin at a given time, what is not in use is literally a massive array of idle disks, which also means the system produces less heat than other large storage systems.

Mean time to repair
In data storage, mean time to repair (MTTR) is the average time before an electronic component can be expected to require repair.

Mean time until data loss
In data storage, mean time until data loss (MTDL) is the average time until a component failure can be expected to cause data loss.

Plural of medium.

Objects on which data can be stored. These include hard disks, floppy disks, CD-ROMs, and tapes.

In computer networks, media refers to the cables linking workstations together. There are many different types of transmission media, the most popular being twisted-pair wire (normal electrical wire), coaxial cable (the type of cable used for cable television), and fiber optic cable (cables made out of glass).

The form and technology used to communicate information. Multimedia presentations, for example, combine sound, pictures, and videos, all of which are different types of media.

Metadata catalog service
Metadata catalog service (MCS) is a mechanism for storing and accessing descriptive metadata and allows users to query for data items based on desired attributes. MCS may be used for storing and accessing metadata about logical files.

Mixed platform environment
A heterogeneous environment that includes multiple platform types.

In the network file system (NFS), a protocol and set of procedures to specify a remote host and file system or directory to be accessed, and their location in the local directory hierarchy.

ms, MS
When spelled ms, short for millisecond, one thousandth of a second. Access times of mass storage devices are often measured in milliseconds.
When spelled MS, short for Microsoft or mobile subscribers.

See heterogeneous environment.

Geographically dispersed; having more than one location.