PAM Programming Manual

Introduction
PAM Programming Manual—142482
1-3
The PAM Subsystem’s Role Within the System
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FESA (Fast Ethernet ServerNet Adapter) on page 1-5
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E4SA (Ethernet 4 ServerNet Adapter) on page 1-5
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TRSA (Token-Ring ServerNet Adapter) on page 1-5
PAM Clients
PAM clients are subsystems or user applications that access the port interface or the
LLC2 interface by using file-system or message-system calls. Examples of applications
include AppleTalk and Open System Interconnection (OSI) subsystems and customer
applications. The SNAX I/O process is a client that accesses the PAM LLC2 interface
using message-system calls.
File-System Interface
The file-system interface is a set of internal procedure calls that enables applications to
communicate with ports on the PAM process.
Message-System Interface
The message-system interface is a set of internal procedure calls that enables the
SNAX/XF and SNAX/APN products to communicate with the PAM process.
Management Interfaces
The PAM management interfaces consist of the Subsystem Control Facility (SCF) and
Subsystem Programmatic Interface (SPI). SCF provides an interactive interface for
control-and-inquiry and accesses the PAM subsystem through SPI.
SPI transfers SCF commands to the PAM subsystem and also provides an interface for
writing management applications that perform control-and-inquiry and event
management. For information about how to write management applications that use SPI,
see the PAM Management Programming Manual.
ServerNet LAN Systems Access (SLSA) Subsystem
PAM uses the SLSA subsystem to access the Ethernet and token-ring LANs attached to
the Himalaya S-series server. SLSA has a logical interface (LIF) which is the point-of-
connection to SLSA for I/O clients (such as PAM).
Logical Interface (LIF)
The LIF in the SLSA subsystem corresponds to the logical interface (LIF) on the
adapter, and thus to one of the Ethernet or token-ring LANs attached to the system.
QIO Shared Memory Segment
The QIO subsystem performs efficient I/O by allowing client processes to transfer data
directly to the QIO shared memory segment and to pass a pointer to the location so that
the actual data doesn’t need to be moved again.