Glossary

ACL

Access control list.

Administrator

Any user whose login name is listed in the BACKUP.UNET operator table with administrator privileges. Grants users privileges for installing and configuring BACKUP.UNET on the network system, and authorization to set up the various parameters for backing up and restoring files.

Algorithm

A special way of solving a certain kind of mathematical problem; a mechanical or recursive computational procedure.

ANSI

An ANSI X3.27-compatible format that allows file splitting and the backup of device-special devices.

Argument

Information supplied to a program to modify or control the program' s behavior.

Background task

A continually running process or program that is not associated with a user's terminal. Also called a detached process.

Backup

A single backup operation that copies specified files or file systems to removable media. A backup may extend over several backup volumes and constitutes either a full or an incremental backup. Also referred to as a dump.

Backup control processor

Acts as a parent process for all backup processes.

Backup control volume

The last volume in a multi-volume backup, or the only volume in a single volume backup. The backup control volume is crucial in performing a full system restore. It contains information about the backup cycle as a whole.

Backup cycle

A full backup and all its associated incremental backups, up to, but not including, the next full backup.

Backup format

The physical layout of data on a backup media volume.

Backup/restore processor

A host that performs backup and restore operations; maintains system backup data information, performs full and incremental backups, and responds to requests for file restores.

Backup segment

A full or an incremental backup stored on a multiple-backup media volume.

Backup volume

A unit of backup media (for example, a cartridge tape, or a tape reel).

BACKUP.UNET home directory

The BACKUP.UNET working directory. It can be specified by the "$NBK" environment variable.

BCP

See Backup control processor.

BCV

See Backup control volume.

Binary directory

Created during installation; includes programs for the GUI and command line interfaces.

Block

A set of bytes defined as a unit. Most UNIX systems define a block as 512 bytes.

Block size

The number of bytes per block allocated for data stored on backup volumes (for example, 512 bytes per block).

BRP

See Backup/restore processor.

BRP daemon

A background task that performs backup and restore services.

Buffer

Internal temporary storage.

Catalog

Contains multiple tables and is used by BACKUP.UNET to control and maintain the networked backup environment. Also see data tables.

Compress

Reducing the size, and therefore the storage requirements, of a data file, by applying a compaction algorithm to remove redundancy in the data.

Cpio

A UNIX backup and restore program. Stands for copy file archives in and out. Allows device special files and raw disk partitions to be backed up.

Cpio -c

The same as cpio; writes header format in ASCII form and is more portable, allowing you to move tapes from one cpio machine to another. This is the BACKUP.UNET default format.

Crash

A critical failure of the UNIX system hardware or software requiring a complete system rebuild (for example, disk head crash).

Cron

A UNIX utility that automatically executes a shell script or program at specified times.

Daemon

A permanent background task, that is, one that is always running.

Data tables

Database tables used to record pertinent information about BACKUP.UNET environment including users, devices, pools, providers, and host information.

DDS

See Device driver server.

Decrypt

To restore encrypted data, by use of a special algorithm, to its original form.

Detached processing

See background task.

Device

A piece of peripheral equipment (for example, hard disk, printer, terminal, or tape drive) logically or physically attached to a machine.

Device driver

System software that interprets device I/O calls for a specific device and controls the operation of that device.

Device driver server

Formats the data according to the backup format and sends the data to the IOD.

Device reselection

Feature of BACKUP.UNET that allows a group of devices to be used during backup operation. The operator can load free volumes in all of the devices acting as providers for a single pool, and during backup processing, when another volume is requested, BACKUP.UNET selects the "best" available device and the backup continues. This feature allows backups to run unattended overnight

Directory

A special file that contains information about other files and subdirectories.

Distributed file system

Software on a local computer that makes files on other (that is, remote) machines appear to be part of the local file system.

Dump

See Backup.

Encrypt

Alter the appearance of data and information by use of a special algorithm to prevent unauthorized people from reading and/or using the data, before transmitting it over the network or writing it to backup media.

Environment

Collection of variable conditions that control the performance of programs and processes. See environment variable.

Environment variable

A symbol, typically created when a person logs on to the computer, or created from the command line, that can be used by shell scripts and by programs. The collection of environment variables constitutes the environment.

Escape processing

The ability of BACKUP.UNET programs to run special shell scripts (processing escapes) to perform additional tasks during backup and restore operations, for example, sending an operator request to mount a tape.

Exit code

The single numerical value (normally 0) returned when a program or shell script completes.

File

(1) Ordinary files contain data/information placed there by a user or application, that is, text files, database records, shell scripts, and binary files. (2) Special files, such as directories and system device files.

File descriptors

Unique file identifiers used to read and write files.

File reader process

Opens, locks, and reads files to be backed up, and passes file data to NWP.

File system

Logical layout of data files on a hard disk.

Foreground task

Processing that prevents the associated terminal from being used for other activity until the current process is complete. Same as an interactive process.

Format

Physical layout of data on media, for example, cpio format.

FRP

See File reader process.

Full backup

Type of backup run when all the files specified in the worklist are backed up; a complete backup.

GUI

Graphical User Interface. An intuitive interface to the BACKUP.UNET software.

Hard link

Two or more identical files linked.

Home directory

Created during installation; includes the online catalog and the log file.

Host/Host system

Computer or computer system; machine within a network.

Incremental backup

Type of backup run when only files in the worklist that have modified or added since the last backup (which may have been full or incremental) are backed up; a partial backup.

Input/output driver

Sends data to tape drives.

Input/output provider

A host with I/O devices, used remotely or locally by BACKUP.UNET components. Responds to requests from BRPs for tape mounts and read or write operations. \

Interactive process

See Foreground task.

Interrupt

I/O specific, asynchronous event sent by device driver or operating system to a currently running program.

Invoke

Initiate a process.

IOD

See Input/output driver.

IOP

See Input/output provider.

IOP daemon

Background task that performs I/O related processes.

Keyword

A special or reserved word.

Link

One of the names by which a file is called. See also, hard link and symbolic link.

Linked files

See Symbolic link.

Local area network (LAN)

A data communication network connecting computers, printers, terminals, workstations, storage devices, and other devices, usually in a limited geographical area.

Local machine

The host machine on which a command is invoked or executed.

Media

The type of storage material used to store backed up data and information (for example, 9-track tapes, cartridge tapes, 8mm tapes, floppy disks, or optical disks).

Media format

The format used to store data and information on a storage volume, for example, tar, and cpio. Backup format to be used for backup and restore processes.

Media pool

A collection of volumes, such as 8mm tapes, that are managed by an IOP.

Media volume

A unit of backup storage media; see also backup volume.

Named backup

Backup explicitly named by the user, rather than automatically (for example, a full backup created for archive purposes). Backups of this type are never recycled automatically.

Named dump

Same as named backup.

Network

A collection of interconnected computer systems that share information, and hardware and software resources.

Network protocols

Rules that control how the machines on a network communicate with each other.

Network writer process

Takes data from FRPs and sends them to the IOP processes to be written to tape.

NFS

Network File System.

NWP

See Network writer process.

ODS

See Original device selection.

Offline

Removes the data portion of a backup from the system. The index portion (with volume information) is still resident on the system.

Online

The data portion and the index portion of a backup is resident on the system.

Operator

Any user whose login name is listed in the BACKUP.UNET operator table, with operator permission. Identifies users who may perform BACKUP.UNET operations, such as mounting and dismounting tapes, and responding to requests initiated by BACKUP.UNET.

Ordinary files

Files that contain data; may be in text, binary, or other data form.

Original device selection (ODS)

A backup option. This is the opposite of Intelligen Device Selection. BACKUP.UNET broadcasts a request to each provider of a pool and selects the first device that responds to the device request. This device is used for the entire backup job. In a multi-volume backup, an operator must be present to mount each volume on the device.

Parallel backup

A BACKUP.UNET feature that uses multiple streams to back up a single host to multiple tape devices simultaneously.

Parameter

A constant, with variable values, used to control a program's behavior.

Participating host/participation system

Computer host system that provides and/or uses BACKUP.UNET services.

Partition

A section of the hard disk.

Partitions file

A special file that contains the full pathname of device special files (one per line) along with the number of data blocks to be backed up.

Pathname

A way in which a file is identified, by the arrangement of directories used to access it (also written "path name").

Pool

A collection of media volumes used to store backed up data and information.

Poolmaster

BACKUP.UNET host assigned to manage the use of a specified pool by BACKUP.UNET hosts.

Processing escape

Potentially suspends processing of a BACKUP.UNET program to invoke another program (for example, a shell script). Once the sub-process has terminated (normally or otherwise), the BACKUP.UNET program resumes execution.

Process

A running program.

Processor

Same as process, but operating on specific data.

Protocol

The procedure used by programs to transfer data to another program or location.

Raw partition

A section of a disk that is not managed by the operating system.

Record

A single entry in a database table containing information about one type of data, for example, a volume record in the volume table or a host record in a host table.

Recycle

The process of making old volumes available for re-use and deleting associated catalog information.

Recycle script

A BACKUP.UNET text file that contains specialized control statements. These statements specify how long to keep backup volumes before recycling them, and automatically freeing them for re-use; when to offline catalog data and information; and to automatically update the online catalog.

Recycled volume

A media storage volume that contains data that is no longer needed or is outdated, and therefore, is available for re-use.

Removable media

Any media (that is, 9-track tape, cartridge tape, or 4mm DAT) that, after removal from the backup device, can be stored on- or off-site.

Restore

The ability to copy files and/or directories from backup volumes onto the hard disk/machine.

Root directory

The primary directory on a computer operating system; has no parent directory.

Root privileges

See root user ID; provides superuser capabilities.

Root userid

Provides permission to access and use all functions and processes on a UNIX operating system; no restrictions.

RPC

Remote Procedure Call.

Script

A plain text file containing instructions to a program.

Semaphore

A locking mechanism.

Shared memory

System memory that is simultaneously available to two or more processes.

Shell

A command interpreter; for example, Bourne shell or C shell.

Socket

A UNIX kernel interprocess communication (IPC) facility.

Spawn

Run (a program or a process).

Special files

Files that do not contain data; may contain references to devices; usually located in the "/dev" directory, but may exist anywhere (for example, disk or device special files).

Special incremental backup

Type of backup run when only files in the worklist that have modified or added since the last backup (which may have been full or special incremental) are backed up; a partial backup. Differs from incremental because the catalogs are not scanned during the backup procedure, thus enabling the backup processing to complete sooner. Skipping the catalog step, however, disables the restore process from recognizing files as deleted.

Storage capacity

The amount of data that BACKUP.UNET stored on a media volume, in blocksize and number of blocks.

Stream

A subset of the files and directories on a host that are backed up to a tape device. Streams are identified in the worklist by a STREAM keyword. Multiple streams can be backed up simultaneously to different devices.

SU/Superuser

See root userid.

Symbolic link

A reference to another file.

Syncro-server

A host responsible for maintaining the BACKUP.UNET global tables (Sys, SysPool, and Pool).

System administrator

See administrator.

System time

Time kept by the computer system, used to track system date dependent processes.

Table

A database file containing specific types of data.

Tar

A UNIX backup and restore format. Stands for tape archive.

User

Any person with the ability to log in to the BACKUP.UNET system.

Utility

A program.

Standard UNIX text editor.

Volume

A single unit of storage media.

Volume label

The electronic label placed at the front of the media.

Volume table update

Daemon that updates the volume table after a backup completes.

VTUP

See Volume table update.

Worklist

A script containing a structured list of file and directory names to be backed up or excluded from backup operations. The worklist also defines backup streams.

Worklist interpreter

Syntactically parses the worklist identifying the files to be backed up.