Distributed Name Service (DNS) Management Programming Manual

Glossary
46958 Tandem Computers Incorporated Glossary–15
SPI control code. A special token code, passed to one of the SPI procedures, that directs
SPI to perform a specified action on the buffer (such as a positioning operation). The
ZSPI-TKN-DATAFLUSH, ZSPI-TKN-DELETE, and ZSPI-TKN-CLEARERR token
codes for SSPUT are examples of SPI control codes. An SPI control code is a kind of
special operation. See also Special operation.
SPI definitions. See also SPI standard definitions.
SPI error number. A number that indicates whether a call to an SPI procedure completed
successfully, or why it failed. This number is returned in the status parameter on calls
to the SPI procedures. The SPI error number does not reflect the success or failure of a
command; it applies only to errors in the building and decoding of a message in an SPI
buffer.
SPI message. A message specially formatted by SPI procedures for communication
between a management application and a subsystem, or between one subsystem and
another. An SPI message consists of a collection of tokens. To retrieve a token from
the message, the application passes a token code to SPI, which scans for the
appropriate token and returns its value to the application. Note that an SPI message is
a single block of information sent at one time (using one file-system procedure call, if
the file system is used). The complete transmittal of a command and the receipt of the
response to it can consist of several exchanges of command and response messages.
SPI message header. The initial part of an SPI message. The first word of this header
always contains the value -28; the remainder of the header contains descriptive
information about the SPI message, most of which is accessible as header tokens. The
tokens in an SPI message header differ according to the header type: the header of a
message that contains a command or response—a standard command header—differs
somewhat from an event-message header. An application can use SSGET or EMSGET
calls to retrieve the values of header tokens, and can use SSPUT calls to change the
values of some. However, there are certain basic differences between header tokens
and other tokens. See also Header token.
SPI procedures. The set of Guardian 90 procedures used to build and decode buffers for
use in system and network management and in certain other applications. These
procedures are SSINIT, SSNULL, SSPUT, SSPUTTKN, SSGET, SSGETTKN, SSMOVE,
and SSMOVETKN.
SPI standard definitions. The set of declarations available for use with SPI procedures
regardless of the subsystem. There is also a set of subsystem-specific declarations for
each subsystem, and some sets of declarations that apply to multiple subsystems. An
application using SPI needs the SPI standard definitions and also the subsystem
definitions for all subsystems with which it communicates. See also Definition files,
and compare with Subsystem definitions.
SS number. See also Subsystem number.
SSID. Abbreviation for the subsystem ID or subsystem descriptor. See those terms.
Standard command header. The header of an SPI message for a command or response. A
standard command header is one kind of SPI message header. Compare with Event-
message header.