Chapter 3. Operating NetView FTP V2.2.1 MVS - IBM

data set control block. A control block containing
specifications for data sets that are to be created.
data transfer message unit. The message unit used
to send the data object.
DCB parameters. Data control block parameters.
decompression. A technique for converting compressed
data back into its original form. Contrast with
compression.
default first qualifier. Server initialization parameter.
Sometimes referred to as the GID initialization parameter.
The server uses this parameter as the first qualifier
when it creates a name for the data set.
default value. The value that is assigned to a parameter
by a program if no value is specified by a user.
deferred request. A waiting request that is temporarily
trapped in the queue. CSA storage was obtained for
NetView FTP, but not enough for the queue handler to
pass the request to a server for processing. The
request is processed later, when more CSA storage is
available to NetView FTP.
delay time. The amount of time a finished request
stays in the request queue before rebuilding the request
queue causes it to be deleted automatically.
direct transfer. Transfer of data from one file to
another file without first storing the data in an intermediate
file.
direct-access storage device. A storage device for
which access time is effectively independent of the
location of the data being accessed.
directory file. In the AIX operating system, a file that
contains information the system needs to access all
types of files.
distribution-service component. A component of
NetView FTP VM that handles communication with the
queue handler (such as retrieving requests to be processed),
and with the network (such as establishing conversations
and transferring files). In NetView FTP VM,
each server consists of one distribution-service component
and up to 32 file-service components.
distribution-service machine. With NetView FTP VM,
a virtual machine in which a distribution-service component
runs.
DSCB. Data set control block.
DTMU. Data transfer message unit.
dynamic allocation. The allocation of a file when it is
needed, not in advance. Contrast with job allocation.
268 NetView FTP V2 MVS Installation, Operation, and Administration
encrypt. To scramble data or convert data to a secret
code that masks the meaning of the data to any unauthorized
recipient.
entry sequence. The order in which records are physically
arranged in auxiliary storage.
entry-sequenced data set. A data set whose records
are loaded without respect to their contents, and whose
relative byte addresses cannot change.
ESDS. Entry-sequenced data set.
ESTAE. Extended specify task abnormal exit.
exceptional checkpointing. To take a checkpoint
when certain types of errors occur.
exchange identification. The ID that is exchanged
with the remote physical unit when an attachment is first
established.
exclude members. To choose those members of a
PDS that are not to be transferred. Contrast with select
members.
exit. A point in a program at which control is passed to
another program.
exit routine. A routine that receives control when a
specified event occurs.
Exit(n) Message Unit. The message unit used to
convey information provided by the Post-Transfer User
Exit routine n (where n is 1 or 2) of the sender to the
receiver.
extended specify task abnormal exit. A macroinstruction
that allows a user to intercept a scheduled
abnormal termination.
FAT. File allocation table.
FBA. Feedback area.
feedback area. An area of storage containing information
related to a queue handler command. For
example, an FBA can contain a request control block, a
query data area, or a server data area.
file allocation table. A table used by DOS and OS/2
to allocate space on a disk for a file and to locate and
chain together parts of the file that may be scattered on
different sectors so that the file can be used in a
random or sequential manner.
file group. One or more files that reside on one
system. For example, all files that are stored in the
same directory or whose file names consist of partly
matching character strings are considered a file group.