1    Introduction to Sharing Software

This chapter describes the concept of software sharing and the components that make up a software sharing environment.

1.1    What is Software Sharing?

A server is a computer system that provides another computer system with required or useful information or resources. The system that uses the information or resources from the server is called a client. A given server can serve one or many clients. Computers in a network can share disk space, lists of names, software kits, processing services, and other entities.

For sharing software using Remote Installation Services (RIS) and Dataless Management Services (DMS), the server supplies software, software kits, and disk space for clients to use.

The DMS and RIS services let you share software in the following ways:

• RIS sets up a system where one or more installable software kits are stored for installation across a local area network (LAN). With RIS, you can buy only one copy of a given software kit. One computer, the RIS server, stores the kit in a special area (called the RIS area) on its disk. Other computers, called RIS clients, can install the software onto their own disks by accessing it across the network instead of from locally mounted distribution media (such as CD-ROM).

• DMS sets up a system in which you can save disk space by sharing the actual operating system software between computers. Without DMS, each computer has a copy of its operating system software on its own disk. With DMS, one computer, acting as a DMS server, stores the software in a special area (called the DMS area) on its disk. Other computers, called DMS clients, run by accessing the software across the local area network (LAN) instead of from their local disks.

The DMS and RIS utilities share architectural similarities; the primary differences are in the contents of their respective server disk areas.

1.2    Benefits of Sharing Software

You can reduce your software and hardware costs by sharing software between computers.

• When you share software with RIS, you have a central location for all the software to install on your system. You do not have to take the software media to the client site, and can install the same software simultaneously on several clients.

• When you share software with DMS, several of the computers in your local area network (LAN) use a single copy of a given piece of software. This reduces the need for multiple copies of the same software, reduces the disk space required for software storage, and allows central administration of software resources.

You are not limited to sharing one piece of software; you can share virtually all of your operating system software.

1.3    Software Sharing Environment

The following components make up the environment for software sharing:

• A server

  The server's system administrator prepares the server for RIS or DMS by installing the operating system and ensuring that the server is connected to a LAN. A single server can serve both DMS and RIS clients, however a client cannot be registered to both DMS and RIS.

• A distribution device on the server

  For most servers, the distribution device is a CD-ROM optical disk driver or a software distribution copied directly to magnetic disk. You transfer or link the software subsets for one or more specific products and architectures from the distribution media to the RIS or DMS areas on the server. Registered clients can then access the software.

• A local area network (LAN)

  You must set up the server and all client processors as hosts on the LAN (using Ethernet, FDDI, or Token Ring for RIS and Ethernet or FDDI for DMS). Clients use the LAN to access the server's DMS and RIS areas.

• Clients

  RIS clients are systems that can run the operating system for which the server provides kits; only these processors can install the base operating system from a server. Layered products can be installed after the client's operating system is running if the processor supports the setld utility.

  DMS clients must be capable of booting over Ethernet or FDDI using the bootp and tftp protocols. Most Alpha workstations and deskside servers have this capability, but some data center servers cannot be configured as DMS clients. Consult your system's user guide and related documentation to determine whether it supports bootp and tftp over Ethernet or FDDI.

  Note

  You cannot use RIS or DMS to install software on DEC 2000 series or DEC 7000 series workstations.