Specifications

Glossary
Glossary-9
raw I/O
Movement of data directly between user address spaces and the device. Raw I/O is used
primarily for administrative functions where the speed of a specific operation is more
important than overall system performance.
raw mode
The method of transmitting data from a terminal to a user without processing. This mode
is defined in the line discipline modules.
read queue
The half of a STREAMS module or driver that passes messages upstream.
routines
A set of instructions that perform a specific task for a program. Driver code consists of
entry-point routines and subordinate routines. Subordinate routines are called by driver
entry-point routines. The entry-point routines are accessed through system tables.
SAP
Service Access Point, conceptually the “point” at which a layer in the OSI model make its
services available to the layer above it.
SBC
Single Board Computer - Motorola MVME1604 (PowerPC 604).
SCSI driver interface (SDI)
A collection of machine-independent input/output controls, functions, and data structures,
that provide a standard interface for writing Small Computer System Interface (SCSI)
drivers.
SDU
Service Data Unit
semantic processing
Semantic processing entails input validation of the characters received from a character
device.
sequential I/O
I/O operations to the same file descriptor that specify that the I/O should begin at the “cur-
rent” file offset.