Appendix A: Glossary of Terms

 < Day Day Up > 


Access Time

A combination of seek time plus rotational latency. This gives the time it takes to access a cluster. Sometimes, people use the term seek time interchangeably with access time.

ATA(Advanced Technology Attachment) Drives

First used for the IBM PC/AT computer; AT, short for Advanced Technology, was a term originally used by IBM in 1984.


In general English usage, the concept of backup means a reserve or substitute; something extra. When used in computing it can mean a copy of data on various types of storage media or a copy of data kept for safety or emergency purposes.

Basic Disks

The partitions or logical drives that were creatable on Windows NT. Later operating systems such as Windows 2000 Professional and Windows 2000 Server automatically default to basic disks unless set otherwise.


To store data temporarily to improve access speed or the location where such data is stored. A way to speed up disk operations is to store the most recently accessed data in memory; therefore, drives now come with several megabytes of cache.

Catastrophic Failure

Fires, floods, earthquakes, explosions, hurricanes, terrorist acts, and more are catastrophic disasters that can destroy an entire organization or a portion or branch of it overnight. This type of occurrence requires offsite facilities and data storage to ensure continuance of business activities.


The smallest unit of storage that the operating system can manage, usually composed of several sectors. The size of the cluster depends on the size of the disk. On small disks of less than 2 MB, the cluster size is 512 bytes, 1 KB, or 2KB depending on the disk size. On hard disks greater than 2 GB, the NTFS default cluster size is 4 KB. As far as the operating system is concerned, all the sectors in the cluster are a single unit.


Existing in many pieces but with all pieces touching, as opposed to split into many pieces.

Contingency Plan (CP)

A plan that addresses non-catastrophic failures that may occur within the organization resulting in some kind of data loss or downtime.


An electronic circuit board or system in a computer that allows the computer to use various peripheral devices. In addition to the logic board contained in the drive itself, today's disks have controllers. These can come as a controller card or as an integrated controller on the motherboard.


Modern-day platters currently contain in excess of 30,000 tracks. On drives that contain multiple platters, all the tracks on all the platters that are at the same distance from the center are referred to as a cylinder. The data from all the tracks in the cylinder can be read by simply switching between the different heads, which is much faster than physically moving the head between different tracks on a single disk.


The process of reorganizing the disk by putting files into contiguous order. This combats the tendency of the operating system to store new data wherever space is available, which results in files being splintered into hundreds or even thousands of pieces. Defragmentation consolidates files into one or more pieces, thereby greatly improving access times.

Desktop Management Interface (DMI)

A management system that can monitor hardware and software components from a central console. Agents are used to gather data once queries are made.

Directory Quotas

A quota given that controls the amount of data that may be stored in a directory or volume regardless of user.

See also Disk Quota.

Disaster Recovery Plan (DRP)

A plan to deal with the operations, technical, and organizational issues that must be addressed to recover rapidly from a disaster of some kind.

Disk Duplexing

Involves using two disks operated by separate controllers and simultaneously recording the data to both disks for reliability and performance. When one disk goes down, the other can still be used for failover. A performance boost can be gotten by setting it up so that a seek operation will be sent to whichever disk offers the quickest turnaround at that time.

Disk Formatting

The creation of the storage layout (file system) on a disk. This is done after the disk is initialized. Without a file system installed on the partition, data cannot be written to it.

See also Formatting.

Disk Initialization

To initialize means to start anew. For hard disks, initialization is necessary to prepare the disk so it is ready for use. This means that the disk is separated into different partitions. A disk can be partitioned into a maximum of four partitions, each of which is assigned a drive letter. Once initialized (or partitioned), the disk is ready to accept the file system and data.

Disk Management Console

The tool used on Windows 2000 to configure disk arrangements. It is a snap-in that is part of the Computer Management function and can be found within the Administrative Tools folder. The Disk Management Console indicates the layout and type of every partition or volume, the file system, the status of the volume, its drive letter, its capacity, any fault tolerant features, amount of available free space, and more.

Disk Optimization (File Optimization)

Said to reduce the time it takes to recover data from disks as well as the time it takes to defragment. Disk optimization involves the intelligent placement of files on a disk in order to minimize head movement and process read/writes faster.

Disk Quota

A quota is an assignment limit or amount for something. In regard to disk space, the quota indicates the maximum amount of space assigned to a user or a directory. Disk quotas, then, control space consumption and prevent one greedy individual, for example, from consuming everyone else's space, leading to system crashes and other unfortunate situations.

Dynamic Disk

A physical disk that can contain dynamic volumes created with Volume Manager. A dynamic volume organizes space on one or more physical disks by using a specific type of volume layout. The five types of dynamic volumes are simple, spanned, mirrored, striped, and RAID-5.

 < Day Day Up > 

Server Disk Management in a Windows Enviornment
Server Disk Management in a Windows Enviornment
Year: 2003
Pages: 197 © 2008-2017.
If you may any questions please contact us: