Glossary

A

API

An application programming interface (API) is a particular set of rules and specifications that a software program can follow to access and make use of the services and resources provided by another software program that implements the interface.

B

BSD

Berkeley Software Distribution (BSD) is the name of any of the series of UNIX specifications or implementations distributed by the University of California Berkeley. The abbreviation "BSD" is usually followed by a number to specify the particular version of UNIX that was distributed (for example, BSD 4.3). Many vendors use BSD specifications as standards for their UNIX products.

C

cache

Cache is a component that stores data so that future requests for that data can be served faster. If requested data is contained in cache memory, this request can be served by simply reading from the cache. This process can be significantly faster than recomputing or fetching data from its original storage location.

cartridge magazine

The cartridge magazine is the removable storage slots of a tape library. It enables the addition or removal of multiple tape carriages at one time.

command line

A command line is a user interface that is navigated by typing commands at prompts. This text-only interface contrasts with the use of a mouse pointer with a graphical user interface to click on options or menus.

D

dcache

See metadata storage.

dentry

Used to keep file or directory attributes, including the file or directory path name, logical size, physical size, time stamps, file UID, extended attributes, and a list of extents. The metadata storage keeps all dentries for the files and directories under the mount point.

dentry cache

See metadata storage.

E

EOD

End of data (EOD) is a dataset on a tape cartridge that denotes the end of user data.

export

A term used in the IBM Storage Archive environment to describe the act of removing a cartridge from the I/O station. To export a cartridge, the medium must be in the I/O station. It cannot be exported from the I/O station, unless the -m ieslot option along with the remove command is specified.

F

FUSE

FUSE

Filesystem in Userspace (FUSE) is a loadable kernel module for Unix-like computer operating systems. It allows non-privileged users to create their own file systems without editing the kernel code. The file system code runs in user space. IBM® Storage Archive runs in this user space.

H

HBA

The host bus adapter is any electronic adapter providing connectivity between a device and its host. There are many types of connection protocol, including Fibre Channel (FC), Serial Attached SCSI (SAS), IP SCSI (iSCSI), serial advanced technology attachment (SATA), Enterprise System CONnection (ESCON), or Fibre Connectivity (FICON®). FICON is the IBM proprietary name for the ANSI FC-SB-3.

I

I/O station

The input/output (I/O) station is a kind of customer accessible storage slot in the cartridge magazine. In order to import or export a cartridge into or from the library, the user opens an I/O station and imports or exports a cartridge into or from the I/O station. The cartridge in the I/O station is moved to one of the empty storage slot for future use.

IBM Storage Archive

IBM Storage Archive is a family of products that enable long-term storage of low activity data (archive): IBM Storage Archive Enterprise Edition; IBM Storage Archive Library Edition; IBM Storage Archive Single Drive Edition.

IBM Storage Archive Library Edition

IBM Storage Archive Library Edition is an application that allows tape media for TS1140, LTO 5 or later generation tape drives to be accessed as file systems on disk drive. The Storage Archive file system program (ltfs) is the main program of Storage Archive Library Edition.

ICU

The International Components for Unicode (ICU) is a mature, portable set of C/C++ and Java™ libraries for Unicode support, software internationalization (I18N) and globalization (G11N), giving applications the same results on all platforms.

import

A term used in the IBM Storage Archive environment to describe the act of inserting a cartridge into the I/O station.

ITDT

The IBM Tape Diagnostic Tool offers multiple functional capabilities that simplify the task of updating tape and library firmware. The tool also provides support for the legacy LTO tape products. It is available for most major platforms and requires no special device drivers.

L

Linear Tape File System

See LTFS.

LFV

The IBM LTFS Format Verifier (LFV) utility is a software application designed to verify media hardware and data compatibility with the LTFS format specification. This is achieved by performing a variety of short and extended checks on LTO cartridges.

lfv

The lfv command is used by the LTFS Format Verifier utility to verify media compatibility.

library operator panel

In a tape library, the operator panel is the built-in display that is equipped with buttons or a keyboard, and located on the front panel or side panel of the tape library.

loopback device

In a Linux® system, a device that can be used as a block device, such as a hard drive, to access files. The IBM Storage Archive Library Edition utilizes the loopback device to store the index of the medium on disk when disk cache is enabled.

ltfs

This is the IBM Storage Archive Library Edition file system program. When ltfs is launched from the command line, IBM Storage Archive attempts to mount a tape medium as a file system using FUSE functions. If the tape medium is formatted for LTFS and is consistent, IBM Storage Archive completes the mount operation successfully.

LTFS

LTFS (Linear Tape File System) is a file system specification that allows Linear Tape-Open (LTO) storage technology to be indexed. Also, the IBM Storage Archive family of products were formerly named IBM Linear Tape File System (LTFS); see IBM Storage Archive. Also contrast with LTFS format.

LTFS format

The LTFS format is a self-describing media format that contains a header prescribing the format for the remainder of the file. The header includes instructions for data arrays, file elements and attributes, and the use of metadata.

LTFS volume

The LTFS volume is composed of the data and index partitions that contain a logical set of files and directories.

ltfscp

An executable program that is used by the IBM LTFS Copy Tool. The LTFS Copy Tool optimizes performance of data transfers through multithreaded operations, memory or disk buffering, and multifile reads from tape that are ordered by location on the tape.

LTO

Linear Tape-Open (or LTO) is a magnetic tape data storage technology originally developed in the late 1990s as an open standards alternative to the proprietary magnetic tape formats that were available at the time.

LTO cartridge memory (CM)

Cartridge memory is built into every data cartridge. It helps to enhance functionality and media reliability by storing access history and media performance information for use by the tape drive every time the cartridge is accessed. Cartridge memory contains the medium auxiliary memory (MAM).

M

MAM

Medium auxiliary memory (MAM) is used to store data that describes the medium and its contents. The data is accessible using READ_ATTRIBUTE/WRITE_ATTRIBUTE commands.

metadata storage

Keeps all dentries under the mount point. Any file or directory under the IBM Storage Archive mount point has a dentry that contains metadata including the file or directory path name, logical size, physical size, time stamps, file UID, extended attributes, and a list of extents. Also referred to as dentry cache. There are two types of metadata storage; on-disk metadata storage (dcache) and memory-based metadata storage.

mount/unmount operation

The mount command is typically used to mount a device or medium to the mount point in a file system. In IBM Storage Archive, the FUSE-based file system mounts a device or medium to the mount point of the file system by using the ltfs command.

The unmount command is used to unmount a device or medium from the file system. In IBM Storage Archive, the FUSE-based file system uses the umountor fusermount command.

O

octal

The base-8 numbering system using digits 0 though 7.

OSF

Open Software Foundation. A nonprofit research and development organization with these goals: to develop specifications and software for use in an open software environment, and to make the specifications and software available to information technology vendors under fair and equitable licensing terms.

R

RAM

Random access memory. A type of memory that provides direct access to any byte on the chip. This "byte addressing" means that the contents of any byte can be read or written without regard to the bytes before or after it. In addition, read and write speeds are symmetrical. It takes no longer to write a byte than it does to read one. In contrast, to write to non-RAM memories such as flash takes considerably longer than reading.

root mount point (library folder)

The directory where the library is mounted. No file or directory can be created by the user below the root mount point. Only read and execute operations are allowed. The root mount point is also referred as a library folder.

S

SAS

Serial attached SCSI. Moves data to and from computer storage devices such as hard drives and tape drives. SAS depends on a point-to-point serial protocol that replaces parallel SCSI bus technology, and it uses the standard SCSI command set. SAS offers backwards-compatibility with second-generation Serial Advanced Technology Attachment (SATA) drives. SATA 3 Gbit/s drives may be connected to SAS backplanes, but SAS drives may not be connected to SATA backplanes.

storage slot

Houses cartridges in the library. When a new cartridge is imported to the library from the I/O station, the cartridge is moved to one of the empty storage slot. When the cartridge is necessary to access the cartridge is moved from the storage slot to a tape drive. If a cartridge in the storage slot is not necessary in the library, the cartridge is moved to one of the I/O station and the user can remove the cartridge from the I/O station.

T

U

utility program

A program used for general support of computer processes, for example, a diagnostic program. It differs from an application primarily in terms of size, complexity, and function.

V

VOLSER

Volume serial number. An identification number that is assigned when a volume is prepared for use on the system. Within a tape library, the VOLSER is usually identical with the physical bar code label on the cartridge.