HP 3000 Manuals HP 3000 Manuals
Introducing NCS Runtime
by Charles Knouse
Information Networks Division
The Network Computing System (NCS) is a set of software application tools
that provide multivendor computing in heterogeneous environments. By
using NCS, an application developer can develop client and server
software to run on a number of different vendor's systems. Originally
developed by HP Apollo for the Domain family of workstations, NCS is now
available on a wide variety of platforms which include:
* HP 3000 Series 900 (MPE)
* HP 9000 (HP-UX)
* DEC VAX (VMS and Ultrix)
* Sun workstations (SunOS)
* IBM workstations (AIX)
The NCS Runtime product (HP36961) provides the ability to run NCS-based
applications on an HP 3000 Series 900 system. It includes: the Remote
Procedur Call (RPC) facility, the Location Brokers, and diagnostic tools.
The NCS Runtime product is bundled with the MPE/iX operating system.
REMOTE PROCEDURE CALLS The main feature of NCS is the RPC facility. RPC
permits an application (the client) to execute one or more procedures on
other systems (the servers) in the network. For each remote call, NCS
sends input parameters from the client to an appropriate server, executes
the procedure in the server, and returns output parameters back to the
client. The client and server programs are established by defined remote
procedures run through the Network Interface Definition Language (NIDL)
compiler (not included with the NCS Runtime). NCS provides the linkage
between the client and server programs through the processing of those
defined remote procedures.
The NCS Runtime software controls the interaction between the client and
server. It packages the RPC parameters into network packets, transmits
the packets between the client and server, and recovers from network
errors (for example, lost or duplicated packets). In addition, if the
client and server systems use different data representations (for
example, an HP 3000 Series 900 and a DEC VAX), NCS automatically
translates data into the appropriate format. All of this is hidden from
the client and server. The application developer need not worry about
the network interface or different system data representations.
LOCATION BROKERS One key problem in client/server applications is how a
client finds the appropriate servers. The NCS Location Brokers solve
this problem. A Location Broker is a program that keeps track of the
locations of servers. A client can ask a Location Broker for the
location of the server for a particular set of procedures (called an
interface). NCS provides the client and server with intrinsics for
registering and finding information through the Location Brokers.
There are two types of Location Brokers. The first is a Local Location
Broker Daemon (LLBD) that runs on every system on the network. The LLBD
knows about the servers that are running on its own local system. The
second Location Broker is the Non-Replicated Global Location Broker
Daemon (NRGLBD) that runs on the network. It knows about all the servers
on the network that are globally registered.
NCS DIAGNOSTIC TOOLS NCS Runtime offers diagnostic tools that can be used
for managing and trouble-shooting NCS applications. The LBADMIN program
allows an administrator to view and modify the Location Broker databases.
The STCODE program maps status codes returned by NCS into error messages.
The NCSPRINT and the NCSMAN tools provide online NCS documentation
capability. The NCKTEST program verifies installation, configuration,
and provides diagnostic information if a problem is detected, and the
UUIDGEN utility generates Universal Unique Identifiers (UUIDs), which are
used in the development of NCS applications.
RELATED INFORMATION The NCS Runtime product provides the software to
execute NCS-based applications. An optional product, the NCS Network
Interface Definition Language (NIDL), provides the software for
developing NCS-based applications on MPE/iX.
For additional information on NCS refer to the following sources:
* Network Computing System Reference Manual (Prentice Hall, HP Part
No. 010200-A00).
* Managing NCS Software (Hewlett-Packard, Part No. 011895-A01).
* NCS Runtime Binary Release Document (installed as part of the NCS
Runtime product, file MANUAL.PUB.HPNCS)
* NCS Manual Pages (installed as part of NCS Runtime).