HP TACL Programming Manual page 220

Glossary
Glossary–8
request. A message formatted and sent to a server by a requester. Requests also
include status messages such as CPU up and CPU down messages, which are placed
on the intended recipient's process message queue ($RECEIVE file) by the operating
system. Contrast with reply.
requester. A process that initiates interprocess communication by sending a request to
another process. Contrast with server.
response. See reply.
retryable error. An error condition returned by the file system that can be corrected by
repeating the operation that caused the error. Sometimes operator intervention is
required before the retry; for example, to put paper into an empty printer. Contrast
with nonretryable error.
secondary extent. A contiguous area of disk storage allocated to a file. A file is made up
of one or more extents; the first extent is the primary extent, and other extents are
secondary extents. The secondary extents are all the same size for a specific file; the
primary extent can be a different size. See also primary extent.
segment. A unit of storage consisting of up to 64 pages of 1,024 words each.
segment file. As used by TACL, a file accessible by TACL that can contain TACL code
and data.
server. The process that receives, acts upon, and replies to messages from requesters.
Contrast with requester.
shared data segment. An extended data segment that can be accessed by more than one
process.
simple data item. A STRUCT item that contains a single value of a specific type.
space-separated list. A list whose entries are separated from each other by a space.
Several built-in functions accept space-separated lists of values.
startup sequence. A convention for sending and receiving certain messages while
starting a new process. By convention, the new process receives an Open message,
followed by a startup message, an assign message for each ASSIGN in effect, a param
message if there are any PARAMs in effect, and then a Close message.
string. A type of argument that some commands and functions accept in place of a
variable. A string can be the name of a variable, text enclosed in quotation marks, or a
concatenation of such entities. The concatenation operator is '+' (the single quotes are
part of the operator). Under control of the QUOTED input format, a quoted string can
contain TACL metacharacters.
STRUCT. A variable that is structured into individual components that can be accessed
individually. Items within a STRUCT can be simple data items, arrays (which can be
further broken down into individual elements), or substructures.
STRUCT item. An element of a structure that can be individually accessed by a name of
the form structure-name:item-name.
substructure. A STRUCT item that is itself a STRUCT.
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