IBM OS/390 User Manual
V
verification test. A test of a system to prove that it
meets all its specified requirements at a particular
stage of its development.
meets all its specified requirements at a particular
stage of its development.
virtual address. The address of a location in virtual
storage. A virtual address must be translated into a
real address in order to process the data in processor
storage.
storage. A virtual address must be translated into a
real address in order to process the data in processor
storage.
virtual address space. (1) In virtual storage systems,
the virtual storage assigned to a batched or terminal
job, a system task, or a task initiated by a command.
(2) In VSE, a subdivision of the virtual address area
available to the user for the allocation of private,
nonshared partitions.
the virtual storage assigned to a batched or terminal
job, a system task, or a task initiated by a command.
(2) In VSE, a subdivision of the virtual address area
available to the user for the allocation of private,
nonshared partitions.
virtual device. A device that appears to the user as a
separate entity, but is actually a shared portion of a
real device; for example, several virtual terminals can
exist simultaneously, but only one is active at any
given time.
separate entity, but is actually a shared portion of a
real device; for example, several virtual terminals can
exist simultaneously, but only one is active at any
given time.
virtual disk. (1) Main storage used as if it were a disk
device. (2) In VM, a physical disk storage device, or a
logical subdivision of a physical disk storage device,
that has its own address, consecutive storage space
for data, and index or description of stored data so
that the data can be accessed.
device. (2) In VM, a physical disk storage device, or a
logical subdivision of a physical disk storage device,
that has its own address, consecutive storage space
for data, and index or description of stored data so
that the data can be accessed.
virtual machine (VM). A virtual data processing
system that appears to be at the exclusive disposal of
a particular user, but whose functions are
accomplished by sharing the resources of a real data
processing system.
system that appears to be at the exclusive disposal of
a particular user, but whose functions are
accomplished by sharing the resources of a real data
processing system.
virtual storage. The storage space that may be
regarded as addressable main storage by the user of
a computer system in which virtual addresses are
mapped into real addresses. The size of virtual
storage is limited by the addressing scheme of the
computer system and by the amount of auxiliary
storage available, not by the actual number of main
storage locations.
regarded as addressable main storage by the user of
a computer system in which virtual addresses are
mapped into real addresses. The size of virtual
storage is limited by the addressing scheme of the
computer system and by the amount of auxiliary
storage available, not by the actual number of main
storage locations.
Virtual Storage Access Method (VSAM). An access
method for indexed or sequential processing of fixed
and variable-length records on direct access devices.
method for indexed or sequential processing of fixed
and variable-length records on direct access devices.
volume label. An area on a standard label tape used
to identify the tape volume and its owner. This area is
the first 80 bytes and contains VOL 1 in the first four
positions.
to identify the tape volume and its owner. This area is
the first 80 bytes and contains VOL 1 in the first four
positions.
volume serial number. A number in a volume label
assigned when a volume is prepared for use in a
system.
assigned when a volume is prepared for use in a
system.
VSAM managed space. A user-defined space on disk
that is under the control of VSAM.
that is under the control of VSAM.
VSE (Virtual Storage Extended). Any of the VSE
operating systems and environments.
operating systems and environments.
W
warm start. (1) A restart that allows reuse of
previously initialized input and output work queues.
(2) In VM, the result of an initial program load (IPL)
that does not erase previous system data.
previously initialized input and output work queues.
(2) In VM, the result of an initial program load (IPL)
that does not erase previous system data.
work file. (1) A file used for temporary storage of
data being processed. (2) In sorting, an intermediate
file used for temporary storage of data between
phases.
data being processed. (2) In sorting, an intermediate
file used for temporary storage of data between
phases.
work space. That portion of main storage that is
used by a computer program for temporary storage of
data. Synonymous with working space.
used by a computer program for temporary storage of
data. Synonymous with working space.
write access. In computer security, permission to
write to an object.
write to an object.
Y
Year2000 challenge. The potential problems and its
variations that might be encountered in any level of
computer hardware or software from microcode to
application programs, files, and databases that need
to correctly interpret year-date data represented in
2-digit-year format caused by the transition to the
year 2000.
variations that might be encountered in any level of
computer hardware or software from microcode to
application programs, files, and databases that need
to correctly interpret year-date data represented in
2-digit-year format caused by the transition to the
year 2000.
Year2000 ready. The capability of a Product, when
used in accordance with its associated
documentation, to correctly process, provide and/or
receive date data within and between the 20th and
21st centuries, provided that all products (for
example, hardware, software, and firmware) used with
the Product properly exchange accurate date data
with it.
used in accordance with its associated
documentation, to correctly process, provide and/or
receive date data within and between the 20th and
21st centuries, provided that all products (for
example, hardware, software, and firmware) used with
the Product properly exchange accurate date data
with it.
Year2000 support. The ability to provide Year2000
readiness.
readiness.
Year2000 transition. The process of revising systems
and databases) to correctly process date data both
within and between the 20th and 21st centuries.
and databases) to correctly process date data both
within and between the 20th and 21st centuries.
YY format. Synonymous with 2-digit-year format.
YYYY format. Synonymous with 4-digit-year format
and a subset of CCYY format.
and a subset of CCYY format.
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VSE to OS/390 Migration Workbook