This glossary provides short definitions of some of the terms used in this manual.
Access Control List (ACL)
File protection with an ACL (Access Control List) has not been supported since SECOS V4.0. The ACL file attribute is still contained in the catalog entry but usually contains the value NO (no ACL protection).
In case a file is ACL protected (might be possible for very old data), file access is not possible. In this case, the owner can protect the file with GUARDS. The protection with GUARDS “overwrites” the ACL protection and thus makes the file accessible again.
access method
A conventional data management technique which defines, for the user, the data organization and the method of data transfer between I/O devices and the main memory of the system.
Access methods supported by DMS are:
EAM = Evanescent Access Method
SAM = Sequential Access Method
ISAM = Indexed-Sequential Access Method
UPAM = User Primary Access Method
BTAM = Basic Tape Access Method
Alias Catalog Service (ACS)
Files and job variables can be addressed by means of alias names and stored in special catalogs, the alias catalogs, together with their assignment to the real file/JV. The Alias Catalog Service (ACS) incorporates three basic functions: Alias name definition, catid insertion for temporary spool files and prefix insertion.
alphanumeric
The alphanumeric characters consist of alphabetic and numeric characters, i.e. the letters A-Z and the digits 0-9.
batch mode
An operating mode in which a job is started with an ENTER-JOB or ENTER-PROCEDURE command; in contrast to interactive mode, the sequence of operations is predefined and stored in an ENTER file (started with ENTER-JOB) or in a procedure file (started with ENTER-PROCEDURE).
batch processing
See batch mode.
batch processing
See batch mode.
block
See PAM page, data block.
blocked record
A record in a file in which each data block may contain several records.
BS2000 file
Is a file which is only created and processed by BS2000. BS2000 files on Net-Storage (FILE-TYPE=BS2000) have been supported since BS2000/OSD-BC V9.0. They are located directly on a Net-Storage volume. Open systems may only access them in read mode.
buffer
A contiguous area in main memory into which data is written and from whichdata is read.
CALL procedure
Sequence of commands/statements executed within a job and called by means of the CALL-PROCEDURE command (see the “Commands” manual [3]).
catalog ID
The identifier of a pubset (see pubset Id); it is specified in a full file name or path name in the form :catid:.
class 1 memory
That part of virtual user memory which is occupied by the main memory-resident modules of the Executive. All class 1 pages are marked as privileged and non-pageable. The pages are not mapped on paging memory. The pages remain in main memory throughout the session.
class 5 memory
That part of virtual user memory which contains the pageable areas allocated dynamically by the Executive when needed for a user job.
class 6 memory
That part of virtual user memory containing the user programs; space is allocated dynamically by the Executive.
data block
A block which contains one or more records of a file.
double tape mark
Two directly adjacent tape marks which indicate the logical end-of-tape. Two adjacent tape marks may also occur if the tape contains an empty file or an empty file section; in this case, they are not regarded as a double tape mark, but as two single tape marks.
“Empty” in this sense means that there are no data blocks between the tape marks before the file header labels and after the trailer labels.
Related records are grouped together in a named entity called a file. Typical examples of files are: conventional input and output data of programs; load modules and object module libraries; text information which is created and processed with a file editor.
file control block (FCB)
A file control block contains all the necessary information about a file.
file link name
A name with up to 8 characters which establishes the link between the file control block and the file via the task file table.
file section
That part of a file which is stored on a single tape.
file set
A set of files recorded sequentially on one or more tapes. There must be no sections of other files between the sections of a file.
first in – first out (FIFO)
Queue structure according to which information is processed in the order in which it is input (in contrast to last in – first out, LIFO).
foreign file
A foreign file is a file on a private volume or on a Net-Storage volume which is not cataloged on a pubset.
interactive mode
The operating mode in which a job is initiated at a (remote) terminal and executed; the sequence of processing is not predefined.
job
The totality of all operational sequences between the commands SET-LOGON-PARAMETERS or LOGON and EXIT-JOB or LOGOFF. For this definition, it is immaterial whether the job is already fully defined when it is submitted (batch mode) or whether the individual steps are defined in the course of execution (dialog mode).
label
A record at the beginning or end of a file or tape which is used to identify, describe and/or delimit the tape or file. A label is not regarded as part of the file.Each label is recorded separately in its own block (label block).
label group
An uninterrupted sequence of label sets which delimit a tape, a file section or a file.
A series of statements for the processing of labels.
label identifier
A three-character word which is recorded as part of the label and identifies this label.
label set
An uninterrupted sequence of labels with the same label identifier.
last-byte pointer (LBP)
Pointer to the last valid byte of the last logical block of a PAM file.
last-page pointer (LPP)
Pointer to the last PAM page occupied by a file. In the catalog entry corresponds to the highest-used page.
locate mode
In locate mode, the user requests the address of the current record, which is stored in a buffer area. The user is responsible for the data transfer from and to the buffer.
locate mode
In locate mode, the user requests the address of the current record, which is stored in a buffer area. The user is responsible for the data transfer from and to the buffer.
logical block number (LBN)
(Sequence) numbering of the PAM pages in a file.
move mode
In move mode, the user specifies the position of the record in his/her program. The system is responsible for data transfer from and to the buffer.
move mode
In move mode, the user specifies the position of the record in his program. The system is responsible for data transfer from and to the buffer.
Net client
Implements access to Net-Storage for the operating system using it.
In BS2000 the net client, together with the BS2000 subsystem ONETSTOR, transforms the BS2000 file accesses to corresponding UNIX file accesses and executes them on the net server using NFS.
The net client for SUs /390 and S servers is the HNC, and for SUs x86 and SQ servers the X2000 carrier system.
net server
A file server in the worldwide computer network which provides storage space (Network Attached Storage, NAS) for use by other servers and offers corresponding file server services.
Storage space provided by a net server in the computer network and storage space released for use by foreign servers. Net-Storage can be a file system or also just a node in the net server’s file system.
Net-Storage file
Is a file which is created on a Net-Storage volume. On Net-Storage a distinction is made between the two file types BS2000 file and node file.
Net-Storage volume
Net-Storage volumes represent Net-Storage in BS2000 which provides systems support as an enhancement of data pubsets.
Net-Storage volumes are addressed by means of their Volume Serial Number (VSN) and the volume type NETSTOR. In the released file system of the net server the VSN of the Net-Storage volume corresponds to the directory
containing the user files and metadata.
NFS (Network File System)
BS2000 software product which enables distributed data storage in a heterogeneous computer network. The user can access remote files as if they were present on his/her local computer.
NFS thus supports connectivity between systems. In addition, NFS enables files to be saved automatically and reliably by BS2000.
node file
Is a Net-Storage file (FILE-TYPE=NODE-FILE) which can be created and processed by both BS2000 and open systems. Node files are supported in BS2000 OSD/BC V10.0 and higher. They are located on a Net-Storage volume in a userspecific directory (name of the user ID), and the file names comply with the BS2000 naming conventions.
null file
A file which is logically empty, i.e. a file which is cataloged and to which the systemhas allocated space, but contains no data.
PAM page
Contiguous storage space of 2048 bytes, beginning at an address divisible by 2048 ́.
privileged mode/program
All parts of the operating system that are not executed in the nonprivileged processing state.
procedure/procedure file
A file which contains a predefined sequence of commands or statements used for program input. Procedures are started with CALL-PROCEDURE or ENTER-PROCEDURE. Only if the file contains an ENTER job will it be started with ENTER-JOB. For detailed information on procedures, see the "Commands" manual [3]).
Term previously used for: pubset; see Glossary (BS2000 V21.0A DMS Intro 2021-06, #334)
pubset
A set of disks designated as public. MPVS systems work with several mutually independent pubsets.
pubset Id
The pubset identifier. If the volume serial number of a public volume begins with the three characters “PUB”, the pubset Id is the fourth character; if the volume serial number contains a period, the pubset Id is formed by the characters preceding the period. In the path name the pubset Id is specified in the format :catid: (see catalog ID).
PVS Id
See pubset Id.
record
A group of data items which are treated as a logical unit.
fixed-length record:
A record in a file in which all records are declared as having the same length; no record length information is needed within the file.
variable-length record:
A record in a file in which the records may have different lengths. The record length must be specified in the first word in each record. This record length field is included in the length of the record; it is 4 bytes long and contains the record length left-aligned in decimal or hexadecimal.
record format
The definition of the length and segmentation of records for a file.
Record format V:
if a format V tape is written with non-EBCDIC code, the length is specified in hexadecimal notation.
Record format D:
if a format D tape is written with ISO 7-bit code, the length is specified as a four-digit decimal number.
shareable file
A file which is cataloged with the USER-ACCESS=ALL-USERS. A shareable file can be accessed from all user IDs provided the other protection attributes (e.g. file passwords) of the file permit this.
spoolout
Automatic spoolout: automatic output of the contents of system file SYSLST to a printer or by sending it by email when a job terminates (EXIT-JOB or LOGOFF)
See system files; the SYSFILE environment consists of all the system files assigned to a job.
system files
System input/output files that are assigned to a job.
The (default) file names SYSDTA, SYSSTMT, SYSCMD, SYSIPT, SYSLST, SYSLST01, SYSLST02, ..., SYSLST99, SYSOPT and SYSOUT refer to the (system) files for data and command input to the operating system or for data output by the operating system. Each of these files is created by the task and specifies predefined I/O areas.
The user can cancel the primary assignment and assign the (default) file names to his/her own cataloged files or compound S variables (when the software product SDFG-P is used).
For detailed information on system files, see the "Commands" manual [3].
tape (volume)
An exchangeable unit of the data storage medium magnetic tape or magnetic tape cartridge. A tape may contain all or part of one file, several files and/or one or more file sections.
tape mark
A tape block which marks the boundary between data blocks and the tape label groups and also between certain label groups. The format of the tape mark is defined in the related standards for magnetic tapes.
tape set table (TST)
A table which shows the tapes requested for a job (together with the TFT).
task file table (TFT)
A table created using the LINK-NAME operand of the ADD-FILE-LINK command and from which the file and processing attributes are taken and entered in the file control block when a file is opened.
task sequence number (TSN)
The sequential number assigned by the system to the task (or job) with which the user can identify a task in some commands.
TSN (= task sequence number)
See task sequence number (TSN).
unblocked record
A record in a file in which each data block may contain only one record.
volume sequence number (VSEQ)
The number of a file section in a multivolume file.
volume serial number (VSN)
A six-character string assigned to the volume when it is initialized (VOLIN or INIT). It is kept in the standard volume label and is used to identify the volume.
volume set
The tape or tapes on which the files of a file set are stored.
volume table of contents (VTOC)
Directory in the F1 label of a private disk or on a Net-Storage volume.