As organizations become increasingly dependent on LANS, it likewise becomes vital that these networks be reliable and well-maintained. This article focuses on the issues involved with support and maintenance of a LAN in the library environment and will include tips on how to effectively manage CD-ROM products on a network. The overall intent of this article lies in providing ways that a network administrator can use preventative maintenance to catch problems, whenever possible, before they happen and to suggest ways to perform software changes and updates easily with the least possible interruption of access to the network by library users.
LANs involve both hardware and software, and the network administrator must attend to both of these components in order to have a stable network. This first section addresses concerns with the hardware, the network cabling system, the CD-ROM equipment, and the workstations.
Hardware maintenance: keys to network stability
Part of the process in setting up an effective preventive maintenance program should involve a new inspection of the network cabling, communications equipment, and workstations. Take this opportunity to search for weakness or vulnerabilities in the network and to take corrective measures. Once done, ongoing maintenance routines will be simpler and less time-consuming. Once the initial re-inspection and assessment of the network has been performed and all the corrective measures implemented, the organization might consider a regularly scheduled biweekly, or at least monthly, physical checkout of the network.
The network cabling accounts for one of the most susceptible points of failure on a network. It is critical that all network cables be properly installed and tested. Whether it be cables installed within the building structure or the attachment cables between the network interface card of the PC and the wall jack, these cables must be reliable. Since this article is about maintenance and not installation, we will concentrate on how to prevent cable failures with an existing cabling system.
Cable connections, no matter how well they are made during installation, will break if pulled often enough or with enough force. Cables left out in the open sooner or later will get caught on something and will eventually come apart. A rat's nest of network cables, power cords, monitor cables, and the like simply invites this kind of trouble. One effective measure in preventative maintenance lies in keeping all these cables orderly and out of harm's way.
Plastic cable ties should be used generously to hold all unnecessary slack cables into tidy bundles that are free from tangles and to hold all cables in place--and away from any areas that can be accidentally snagged by a foot, chair, vacuum cleaner, or such. Cables should be tied to the point of being neat, orderly and out of the way, but should have enough remaining slack so that the computers can be moved slightly without pulling any cables loose.
All cable attachments should be affixed in the most secure way possible, especially in any public-use portion of the network. Resist the temptation to simply push in monitor and printer cables without tightening the screws that hold them in place--the extra effort of finding a screwdriver will pay itself off in fewer return trips to reattach cables. Along the same lines, make sure that the clips on AUI cables lock into position, that all T-connectors on a thin-wire Ethernet are twisted and locked, and that all RJ-45 connectors in a 10OBASE-T network are pushed into their jacks all the way.
In general, make sure that any type of connector involved in your network takes full advantage of the mechanism that was designed to hold it in place. Any shortcuts taken here will surely cause problems later on.
Network cables should be clearly labeled whenever possible. In the event of a cable failure, the individual investigating the problem should be able to visually identify which cables belong to a given segment, or which attach to a particular repeater or other communications equipment.
CD-ROM drives, especially the older models, require special attention in a network environment. Several different configurations of CD-ROM drives are possible on a network. These drives may be standalone units that attach to individual workstations, multiple standalone drives daisychained to a single workstation, or multiple drives that may be installed into a single CD-ROM optical server tower. Regardless of the type of configuration of the CD-ROM drives, certain practices will improve their reliability.
Dust within a CD-ROM drive will cause errors in reading data from the disc. Older drives fall victim to this problem much more often than more recent drive models whose design includes multiple barriers against dust contamination. Not only do the more modem drives seal themselves more effectively than the older ones, but the tower enclosures currently offered from vendors such as CBIS and Meridian Data provide an additional layer of protection.
The amount of effort necessary to combat dust contamination will depend both on the types of CD-ROM drives installed on the network and also on the general level of dust in the building. With the computer equipment that I deal with, I can see a great deal of variation from one building to another.
One of the most important tools for dealing with dust in computer equipment in general, and CD-ROM drives in particular, is a good vacuum cleaner. You will need one that is portable enough to use easily, yet powerful enough to effectively remove dust from the equipment. A midsize unit with a shoulder strap and a narrow nozzle attachment should suffice. The hand-held, battery-powered units often advertised for cleaning computer equipment are not powerful enough to be effective.
How often you need to vacuum out your equipment will vary. Some of the CD-ROM towers that I deal with have the old-style Toshiba XM-3201B drives and reside in a building with a particularly bad dust problem. These drives develop disc read errors if we go more than two or three weeks between vacuuming. Drives in other buildings on campus require cleaning only once every two or three months.
The use of a CD cleaning disc can also reduce problems in reading data from CD-ROM discs. These cleaning discs are the same as ones used for audio compact discs, and can be purchased from most audio equipment dealers. The use of a cleaning disc every two weeks should help avoid data errors reading the discs.
Another concern with CD-ROM drives lies with the discs themselves. Excessive handling of the discs can lead to fingerprints and scratches on the data surface which will also cause data read errors. The discs should be cleaned periodically with a soft lint-free cloth and handled as little as possible. Some drives use caddies that protect the disc, but even these allow a certain amount of dust accumulation on the disc surface. The overall concern here is to design procedures for the operation of the CD-ROM network that involves as little shuffling of the discs as possible.
The preventative maintenance on microcomputers used as stations on a LAN does not differ greatly from those not on a network. I include here some general advice on microcomputer hardware maintenance, but concentrate on aspects that seem particularly important for CD-ROM network workstations.
Microcomputer hardware in general does not require a large amount of preventative maintenance. There are few mechanical parts that are subject to wear, and component failures are extremely difficult to predict in advance. It just is not possible to determine whether a particular board or drive may be about to fail and should be replaced before it does. Two of the most helpful maintenance procedures involve disk optimization and dust removal.
Microcomputers, like CD-ROM drives, need at least some protection from excessive dust contamination. Anytime you need to open a microcomputer case, whether it be to install a new card or make a simple repair, it is important to take the time to vacuum out the entire system unit. Dust accumulation inside a PC can lead to overheating and may eventually cause problems with connections on the system bus and can lead to problems with mechanical components such as disk drives. It is much better to take the time to remove all accumulated dust while the system is open anyway than to wait until symptoms develop. I do not necessarily recommend periodically taking systems apart just for vacuuming. The process of taking a system apart can itself occasionally trigger a failure.
There are some steps that any organization can take to ensure that the hard drives of CD-ROM network stations perform optimally. Fragmentation of files on a hard disk impedes the perceived performance of the system. This especially effects stations on a CD-ROM network where the search software loads from the local hard drive. Even on networks where the search software resides on a file server, the CD-ROM search application will write intermediate files to the local hard drive. The search software may also occasionally leave behind an improperly closed disk file, especially if one reboots the system before properly exiting the software.
In order to maintain optimal operating performance of a CD-ROM workstation, a good preventive maintenance procedure might include the use of a disk-optimizing tool that eliminates the fragmentation of disk files and removes all improperly closed files and cures other common disk problems. The Norton Utilities, distributed by Symantic and PC Tools from Central Point Software both include software for these functions.
Software Maintenance Tips
The management and maintenance of software on a CD-ROM network and the installation of updated CD-ROM data discs and associated software constitutes a major part of the upkeep of a CD-ROM network.
One key to efficient software management on a CD-ROM network lies in the ability to perform as much of the work as possible from a workstation other than the public CD-ROM workstations. This allows the process of installing and configuring new products on the network to be done behind the scenes without excessive interruption of access to the CD-ROM network to users.
Mounting Search Software
Whenever possible, the search software for CD-ROM products and the workstation's menu utilities should be loaded from a file server rather than on the hard disks of the workstations. This strategy greatly simplifies the process of installing new products and updates existing ones. Even while patrons continue to use the CD-ROM LAN, the network administrator can install a new version of the software onto the file server and make the necessary configuration adjustments. Once this process is complete, the menu utilities on the CD-ROM stations, which are also loaded and configured from the file server, can be adjusted so that the workstations load the new version rather than the old, and any new discs can be loaded into their respective drives.
As a general principle, as much of the workstation's software and configuration files should reside on the file server as possible. It is much easier to make changes and updates one time on the file server than it would be to have to update each workstation individually.
Most CD-ROM networks use some type of menu system from which the library users can select among multiple CD-ROM products or other software. It is important that the menu system be one that can be configured and changed via the network. A great deal of the work of maintaining a network lies in the process of making product changes and updates. This ability becomes increasing important to networks that sport a large number of workstations.
The file server should even have copies of files that must reside on the workstation such as the AUTOEXEC.BAT, CONFIG.SYS files, and all of the network and CD-ROM drivers. Even in the event of a total hard disk failure, all that the network administrator need do is to replace the drive, boot from a floppy disk with the network drivers, log into the network and copy the necessary files from the file server to the freshly formatted drive. Likewise, if changes become necessary to any of the files that reside on the workstations, they can be installed from the network file server instead of carrying a floppy disk to each workstation.
All important files should be protected against accidental modification or deletion. Network administrators should be careful to set all configuration files on the file server and on the workstation as read-only. Most network administrators will choose to prevent users from exiting the menu interface and accessing DOS. Most menu utilities have features that allow one to exit to DOS only after providing a password. Such a system allows convenient access to DOS to authorized staff for maintenance and troubleshooting, but keeps users away from the vulnerable configuration files.
Another chore that should be done as part of regular software maintenance lies in scanning the workstation's disk for stray files. Such files would include search requests that may have been downloaded to the hard drive instead of a floppy disk. Also, look for unneeded temporary files that often remain when one reboots the PC before exiting the search software.
Still another aspect of the care and maintenance of a CD-ROM network is establishing some protection against computer viruses. How aggressively you approach this problem may depend on your environment. If your site has a history of a number of computer virus infections, the network administrator may elect to purchase and install one of the commercial virus protection utilities, and regularly install the updates. For some sites, the threat of computer viruses is not as much of a consideration.
All software that resides on a file server must be protected against infection by computer viruses. Most network administrators know how vital it is that all software files on a file server should be flagged as "read-only" and to never allow a normal user to access a software directory with "write" access. Further, the entire file server should be scanned periodically for the presence of any known viruses. This applies to all software on the server, not just that associated with the CD-ROM network.
Computer viruses pose less of a threat to CD-ROM workstations than they might to other types of microcomputers. No unique data or software resides on these workstations. If a system becomes infected, it might be just as easy to re-format the drive and reinstall the software from the network than to take all the steps necessary to ensure that the virus has been removed. The danger lies much more in a CD-ROM station passing a virus along to other microcomputers in the library and beyond through disks used for downloading search results.
There are probably lots of other procedures that network administrators will discover that will make their network stable and reliable. It is important to take the time to assess the network and to anticipate problems before they happen, and to be prepared once they do.