HP 3000 Manuals HP 3000 Manuals
GLOSSARY
access
The process of obtaining data from files or acquiring the use of a
device. Access implies an input/output (I/O) operation, and is used as a
synonym for I/O.
archiving
Storing infrequently used or out-of-date files onto tape and permanently
removing them from the system disks at the same time.
backreference
The technique of using an asterisk (*) before a formal file designator to
indicate that it has been previously defined during the current session
or job with the FILE command.
backup
The process that duplicates computer data to offline media, such as a
magnetic tape. Backups protect data if a system problem should occur.
backup devices
System peripherals that allow you to write information to, and read
information from, backup media.
batch processing
A method of submitting a job for processing. A job, which is submitted
as a single entity, can consist of multiple commands such as program
compilation and execution, file manipulation, or utility functions. Once
submitted, no further interaction between the user and the job is
necessary.
byte
A combination of eight consecutive bits treated as a unit. A byte
represents one letter or number within the computer. The size of memory
and disk storage is measured in bytes.
character
A letter, number , or symbol represented by one byte of data.
character set
A series of characters to substitute for a single character to name a
group of files.
command
A system-reserved word that directs the operating system, a subsystem, or
a utility program to perform a specific operation.
command file
1) A file a user creates to execute multiple commands. To execute a
command file, enter the command file name at the system prompt.
2) A set of one or more SQL or ISQL commands in a file that can be
executed with the ISQL START command.
compatibility mode(CM)
Compatibility mode provides object code compatibility between MPE
V/E-based systems and the 900 Series HP 3000. Compatibility mode allows
current Hewlett-Packard customers to move applications and data to the
900 Series HP 3000 without changes or recompilation.
computer
A device that accepts information, processes it, and supplies an output.
A computer usually contains memory, a control unit, arithmetic and
logical manipulations, and a means for input and output.
concurrent backup devices
A set of multiple, concurrently accessible backup devices to which you
are able to store information simultaneously.
consecutive backup devices
A set of multiple backup devices used for a given tapeset to which you
are able to store information sequentially.
console
See system console.
cursor
A flashing rectangle or blinking underline character on a display screen
that marks the position where text or data can be entered, changed, or
deleted.
DAT
Digital Audio Tape. A data storage media used by the HP 1300H DDS-format
device.
database
An integrated collection of logically related data files and the
structural information about the data.
data compression
The use of data compression algorithms on the host system to reduce the
amount of data transferred to the output device.
DDS
Digital Data Storage. A format for storing computer data on DAT
cassettes.
default
A predefined value or condition that is assumed by the operating system
if no other value or condition is specified.
device
See peripheral.
device class
A collection of devices that have some user-defined relation. The MPE XL
file system supports a means of maintaining collections of devices but is
cognizant of the relation only for certain MPE device class names.
device pool
A series of identical backup devices.
device type
Device types are defined by a number. For example, 0 represents a
moving-head disk and 16 is the class type number assigned to line
printers.
disk
A circular plate of magnetically coated material used to store computer
data. A disk may be fixed, removable, hard, or flexible.
dynamic backup
Dynamic backup means that the STORE file set and structures are
accessible for any access while the backup is taking place. Any
modifications made to the STORE file set during the backup are logged and
saved along with the data on the backup medium. On RESTORE, the data and
log file are used to recover the data to a consistent state.
error messages
Messages describing errors occurring during either an interactive session
or a batch job. The messages are reported to the standard list device,
which is usually a terminal (for a session) or a line printer (for a
job).
execute
When a command is entered, the computer carries out the instructions or
performs the routine indicated.
file
A group of related records that represents ASCII text (text files) or
binary data (such as executable code). Every file must have a file name
so that the user can access the file's contents.
file equation
A method of equating a file name to a device or another file. The MPE XL
FILE command is used to establish the relationship of the file to the
device. Generally used to direct the input to or output from a program,
job, or session to a particular device by referencing the device class,
such as TAPE or LP.
file name
On an MPE system, a string of up to eight characters used to identify a
file. The file name is assigned to the file when it is saved. The first
character must be an alphabetic character; the others may be alphanumeric
characters.
fixed disk
A large capacity disk that is fixed inside a disk drive. Unlike flexible
disks, a fixed disk cannot be removed.
flexible disk
A random access storage device, also called a diskette or floppy disk.
Data may be written to or read from one or both sides with a special disk
drive intended only for diskettes. Flexible disks are often used with
personal computers.
fully-qualified file name
A complete file description, including the file name, the group to which
the file belongs, and the account name. The fully qualified file name of
the LETTER file in the PUB group of the SYS account is expressed as
LETTER.PUB.SYS.
hard disk
A device used to store information. A hard disk has more storage than a
floppy disk without being susceptible to the same hazards (for example,
being bent or having the media corrupted by physical handling).
hardware
All the physical components and devices of the computer, including the
CPU cabinet, tape drives, disk drives, terminals, and other peripherals.
independent files
Files which require only single file consistency.
indirect file
A text file containing the parameters for a STORE or RESTORE command that
you execute regularly.
initialize
To set the known default values.
input
The data to be processed, or the process of transferring data from
external storage to the computer.
input/output (I/O)
The process of, or equipment used in, transmitting information to or from
the computer.
interleave
A method of writing data to a disk device for the purpose of improving
data access speed.
I/O error
A data transmission error between a computer and peripheral. Examples of
I/O errors are baud rate or parity mismatch, and incorrect syntax in
device-control instructions.
job
A single file, submitted by a user, containing operating system and
utility commands and references to the files to be manipulated.
media
Devices capable of storing data, such as disks or magnetic tape.
media name
The name of the media set to make available for use by TurboSTORE/XL II.
The media name is the name assigned during the STORE operation.
media sub-name
The name of the surface within the media set to use. The media sub-name
is the sub-name assigned during the STORE operation.
message
A unit of information sent from one device or computer to another in a
form that is understandable to the receiving device.
mounting
The act of making a data storage device accessible. To physically mount
the device, you load the media onto the device. To logically mount the
device, you tell the operating system which device you want to use, and
it allows you access to that device.
MPE XL
Multi-programming executive with extended large addressing: The
operating system for 900 Series HP 3000 computers. MPE XL manages all
system resources and coordinates the execution of all programs running on
the system.
native mode (NM)
The native run-time environment of MPE XL. In native mode, source code
has been compiled into the native instruction set of the 900 Series HP
3000.
online backup
Online backup means that the STORE file set and structures are accessible
for any access while the backup is taking place. Any modifications made
to the STORE file set during the backup are logged and saved along with
the data on the backup medium. On RESTORE, the data and log file are
used to recover the data to a consistent state.
operating system
The software that operates the computer. It consists of programs such as
basic file and I/O manipulators. All subsystems run upon the operating
system.
output
Data transferred from internal to secondary (external) storage in a
computer. Also, the process of transferring information from the
computer to a peripheral device.
parallel devices
A set of backup devices to which you are able to store information
simultaneously.
parameter
A value in a list of values that is passed to a procedure. The parameter
is used on calculations or operations in the procedure.
password
A string of ASCII characters used to verify the identity of a user.
Passwords are associated with users, groups, and accounts.
peripheral
A hardware device attached to and controlled by a computer, such as a
terminal, a tape or disk drive, or a printer.
program
A sequence of instructions that tells the computer how to perform a
specific task.
PUB group
A group, created when an account is created, whose files are usually
accessible to all users within the account.
PUB.SYS
The public group of the system account. This is where programs and
applications available to all users of the system reside.
purge
To delete a permanent file from the system with the PURGE command. The
PURGE command is also used to delete an account structure entry such as a
user name, a group name, or an account.
required parameter
A parameter that is required when entering a command or calling an
intrinsic. In reference manuals, required parameters are surrounded by
braces ({}).
restore
The process of retrieving user files from SYSGEN (MPE XL), SYSDUMP (MPE
V/E), and STORE tapes or serial disk and writing them to disk. Restoring
is executed with the RESTORE command.
scratch tapes
Used tapes containing information that is no longer needed.
sequential
A manner in which information may be read from or written to a device.
Sequentially accessed files are stored in such a way that the logical
order of the file's record is identical to their physical layout on disk
or tape.
session
A mode in which the HP 3000 is used interactively by entering commands
and data through a terminal's keyboard and receiving immediate responses
to input. A session is initiated with the HELLO command. A session is
ended with the BYE command, or a second HELLO command that logs the user
off the first session and onto another session.
shadow logging
A method of saving the "before" images of file blocks when the records in
the file block are modified during online backup. The before images are
stored on tape and are used by RESTORE to reconstruct the original
contents of the file.
single file consistency
Single file consistency is the preservation of the internal state of a
file. The backup system ensures that a file is in a logically consistent
state before it stores the file.
static backup
Backup is static when the files and structures are inaccessible during
the time that they are being stored. That is, they are locked
exclusively by the backup subsystem.
storage device
A device (such as a disk pack, a disk cartridge, a flexible disk,
magnetic tape, or cartridge tape), onto which data can be stored and
subsequently retrieved.
store
1)The process of saving files to tape or serial disk. Storing is
executed by using the STORE command.
2)A machine instruction that tells the CPU to take information from a
register and put it into memory.
SYS account
A special account, included with the system when it is first installed.
It contains all MPE files, supported subsystems, utility programs, and
compilers.
system
A group of one or more CPUs that communicate through buses without the
use of data communications software.
system console
1)A workstation given a unique status by the operating system. It is
used by the operator to execute specific commands for the purpose of
managing sessions, jobs, and system resources. It is associated with all
boot or system loader error messages, system error messages, and certain
system status messages.
2)The terminal, usually logical device 20, that the system operator uses
to monitor system activity, respond to resource requests, and send
messages to user's terminals. The console (and its associated privileges
and responsibilities) may be transferred to another logical device with
the CONSOLE command.
system file directory
A directory maintained by MPE that records the name, group, and account
of each permanent file on the system. The directory contains the size of
each file, its location on the disk, who may access it, and other
information.
system manager
The person who manages the computer installation, responsible for
creating accounts and assigning capabilities and resource-use limits to
each.
tape request
A printed message at the console asking for a backup device to be
assigned to a user.
transport backup
Transport refers to the movement of files between MPE V/E and MPE XL
systems using backup media. MPE XL backup and recovery provides a
compatibility option with which an MPE V/E-compatible tape may be created
or read.
user
Anyone logged on to a session, using a local or remote terminal to
interact with the computer. Each user is identified by a user and
account name, and can access files in the logon group.
utility program
An operating system program that performs specific functions such as file
copying, sorting and merging, memory dump analysis, or monitoring
available disk space.
volume
A volume is one-disk pack. Each volume is a member of a volume set and
contains a volume label, a label table, and a free space map.
volume class
Volume classes are used for the allocation and restriction of disk space.
A volume class is a logical subset or partition within a volume set and
can bridge any number of physical member volumes of a volume set.
volume set
A volume set is a group of from 1 to 255 related disk packs. One volume
of the volume set must be designated as the master volume for the set.
Each volume set is assigned a name by which it is identified and
referenced.
wildcard
A symbol that is used to replace a character or set of characters. In
MPE, the "at sign" (@), the "pound sign"(#), and the question mark (?)
are used as wildcard characters. Other subsystems may use different
symbols.
write-enable
To remove a disk's write-protection, allowing the disk to be written
upon.
write-protect
To protect stored data so that it cannot be overwritten.
write ring
A plastic ring that fits onto the inner groove of a reel-to-reel tape,
enabling you to write information onto the tape.