NODES

The computers, or nodes, in a network may be used for workstations, servers, or both. PCs need a network interface card (NIC) installed for networking capabilities.

The NICs mediate between the computer and the network by doing the necessary processing and translation to enable users to send or receive commands and data over the network. NICs are designed to support a particular network architecture, such as EthernetR or ARCnetR.

A server may be dedicated or nondedicated. Dedicated servers are used only as a server, not as a workstation. Nondedicated servers are used both as a server and a workstation. Networks with a dedicated server are known as server-based networks; those with nondedicated servers are known as peer-to peer networks.

DEDICATED SERVERS

Dedicated servers cannot be used for ordinary work. In fact, access to the server is often limited to prevent any access by unauthorized users.

Most of the high-end network packages assume you are using a dedicated server. If the network has a dedicated server, it is most likely a file server.

A dedicated fileserver runs the NOS software, and workstations run smaller programs whose function is to direct user commands to the workstation's operating system or to the server. Both servers and workstations need NICs to function on the network.

NONDEDICATED SERVERS

A nondedicated server can be used as a workstation as well as a server. Using a server as a workstation has several disadvantages and is not advisable for larger networks.

The following are disadvantages of nondedicated servers as compared to dedicated servers:

l Many of the NOSs that allow the nondedicated server to run with DOS make them extremely slow and clumsy. While most dedicated servers have software that replaces DOS, such systems may also require a separate non-DOS partition on the hard disk. This allows the NOS to arrange and deal with the contents of the partition in a way that optimizes performance.

l Running applications on a DOS machine while it is also supposed to be running a network can lead to a deadly performance degradation.

l Certain tasks will tie up a DOS machine, effectively stopping the network until the task is finished.

l Adequate security is more difficult to maintain on a nondedicated server.

SUMMARY

In this chapter we discussed the different types of network components and their functions. We described cabling and the connectors used to connect the network hardware. We covered the purpose of the server and the differences between a dedicated and a nondedicated server. Remember, the driving factor for the type of hardware and cabling used is the topology of the network.