ANALYZE CONFIGURATION

Analyzing the configuration of the network can be accomplished in two different ways. The first and simplest way happens when the computer is turned on; the operating system goes out and checks the configuration. The second way is accomplished by using an application to test whether a remote device is properly connected to the system. The use of an application is the best way to analyze the configuration.

The application tests the remote device by sending out a signal to each device and waiting for the signal to return. This process is called "pinging." The ping sent out is called an echo message, and the reply is called an echo reply message. The application sends out the echo message and, if the device is properly connected, it sends back an echo reply message. The receipt of this echo reply indicates that there is a viable connection. Some version of application software reports on how long it took to receive the echo reply and any lost replies. These reports provide information about the traffic and noise levels on the network.

SYSTEM RESOURCE LIMITS

The advantage of a network is it allows several people to share resources, both hardware and software. Hardware resources refer to printers, disk drives, CDrom drives, scanners, and modems. Software resources include operating system, drivers, applications (word processing, database, etc.), management software, and data files. To avoid problems, such as slow response time and unavailability of resources, you must know the limits of the system resources.

Hardware Limits

The limitation involved with hardware is going to be waiting. A particular piece of peripheral equipment can be accessed by one user at a time. Only one job can be printed at a time, and only one user can be using a single modem at a time. This small inconvenience of access outweighs the cost of several different pieces of the same type (i.e., several printers or modems).

Software Limits

No matter which software package, whether application, mail, or operating system, there is a limited number of users that can use the software at one time. It is far cheaper to buy one multi-user package that allows for 25 users than to purchase 25 individual copies. But, it might run just a bit slower than an individual copy.

NETWORK SOFTWARE

Networks require the interaction of software and hardware. The system software to operate and control the network must be specifically designed for network operation. The application software/programs to solve user problems must also be specially designed to run on a network. Between the system software and the application software/programs, two pieces of software are needed. One is the telecommunications access software. It provides application programs access to the network so they can send and receive data. The other is the teleprocessing monitor, which is the interface between the telecommunications access software and the application programs. It handles the details of integrating these two. To install the system software, as with any software, follow the installation instructions supplied with the software.

SYSTEM SOFTWARE

It takes special system software to handle the unique and dynamic workloads of a network. This special software is called network system software. The network system software is sometimes referred to as the network operating system (NOS). It is different from the type of system software you normally use on your stand-alone PC. Network system software must be able to handle multiple users, multiple peripherals, network security, and be able to share information and application software, just to name a few differences. Normally, network system software runs on the network server. It includes such things as the network's operating system software, communications software, and all the programs needed to manage the sharing of information and resources on the network. Without it, there would be no way to coordinate and manage the many components of a network into a functioning whole.

Network system software provides multitasking capabilities. If the network is to serve multiple users at the same time, then the server must be able to perform tasks so fast they appear to be processed simultaneously. An example of multitasking is to have the network server transfer a message (using a program called E-mail) from one PC to another, save a 50-page document to hard disk, and send a report to a printer, in rapid succession. Only systems with multiple processors, such as a system with two 386 or 486 microprocessors, can process information simultaneously.

Network system software provides utility programs, such as electronic mail (or e-mail). E-mail gives network users the ability to send messages to one another over the network. If for some reason you needed to send a message to all the network users, E-mail is capable of sending your message to multiple users. Other utility programs sort, merge, and print files.

Network system software also provides data protection. This includes data security/integrity and backing up of files. Data security is a must if you are to limit access to sensitive and classified information. Data integrity prevents files from being updated by more than one user at a time. There are a number of ways you can control access to information on the network. One way is to divide the shared hard disk into several different sections, similar to making logical partitions. Once the different areas have been established, you can specify how the user can access them. Generally, the different levels of access can be designated for either private, shared, or public use. They are defined as follows: 

. PRIVATE USE Only one user is allowed to access and make changes to the data in this area. For example, all of PO1 Smith's work is located in the area \SMITH. Only PO1 Smith has access to this area, and only she can make changes. 

. SHARED USE All users are allowed to access and make changes to the data in this area. For example, a shared area called \ADMIN could contain correspondence that can be updated by all the command's Yeomen. 

. PUBLIC USE All users are allowed to access this area; however, they cannot make any changes to the data. For example, the area called \DIRECTIV contains all command directives. You would want your users to be able to view the data but not be able to make any changes.

Security and data protection are provided by identification and password security. When the users log on the system, they must enter their correct identification numbers along with their passwords (as a double check) to gain access to information. Another reason why data must be made secure is to prevent unintentional damage that can result when more than one user accesses and changes the same information at the same time. In a case such as this, neither user would know what the other had done, and the result would be corrupted data. To prevent this, network software often provides you with some type of locking capability. This locking feature prevents others from accessing the file or record when you are working on it.

To ensure a well-managed (network), the data must not only be secure, it must also be backed upon a regular basis. Files must be backed up if all the information on the network server's hard disk is to be saved in the event of a hard disk failure, a sudden power surge, or loss of power. Tape backup systems are very effective in that not only the tapes but also the tape units themselves can be stored off-site, which provides for additional security.