LOCAL AREA NETWORKS (LANS) AND (2024)

This paper initially gives a basic introduction of Local Area Networks(LANs). The author does not provide a detailed discussion of this sectionsince it is not the scope of the paper and also because a detailed descriptioncould have taken a highly technical nature. Secondly, the paper deals withthe application of LANs in libraries with some examples from the applicationsin developed countries. Finally, the barriers which we, the developingcountries, encounter in the application of LANs in our libraries are outlined.

2. WHAT ARE LOCAL AREA NETWORKS

Although the term "Networks" can be interpreted in a number of ways,in our context we can interpret it as a collection of computers and peripheraldevices interconnected by a communication medium such as, coaxial cables,twisted pair wires and optical fibers. Three major categories of networkscan be identified, based on their geographical coverage, as follows:

• Wide Area Networks (WANs): Computers and peripherals which are interconnectedover a geographical area of 10 or more kilometers belong to this category.Usually they cover the entire country.

• Metropolitan Area Networks (MANs): This is the type which covers asingle metropo-litan area.

• Local Area Networks (LANs): "...are concerned with the interconnectionof items of computing equipment (office workstations, intelligent instrumentsetc.) which are distributed over a localized area such as a universitycampus or process plant. They are referred to, therefore as Local AreaNetworks". (Halsall, 1988).

LANs can be distinguished from other networks because of their shortdistance. The total coverage may be from 1 km to 10 kms. The data transmissionspeed of LANs is much higher than in other types of networks. When a WANsworks at a speed of 1 mbps, LANs can transmit data at a speed of 1 - 10mbps. The error rate in data transmission is slow because of the shorterdistance between the equipment. Since LANs are within a single buildingor a smaller area, they are owned by the specific organization. This localizedcontrol provides greater flexibility in LANs than other types of networks.

2.1. Evolution of LANs

In the 1960s, the computers predominantly used were mainframes and onlya few organizations were able to afford them because of their high cost.The concept of time sharing was popular during this period. Harnessinga dumb terminal to the mainframe by using a telephone line and leasingor sharing the computer time was the common practice. The major problemwas the slowness of the computing process.

With the advent of minicomputers in the 1970s, a solution for this problemwas found. It could accommodate several terminals and more and more peoplewere able to afford mini computers. Proliferation of minis led to the necessityof a communication between them in order to share the data stored in them.

Computer resources in the organizations further increased with the arrivalof microprocessors and the advanges of integrated circuit technology. (Halsall,1988). It soon became common to find a multiplicity of products by differentmanufacturers physically located within the same building. Although theycould act as autonomous computers, it was often required to establish acommunica-tion with each other. As microcomputers became more and morepowerful and less and less expensive, more people were using them and havingtheir own databases and exchanging data. The communication facility providedis referred to as a private Local Area Data Network. Therefore, it is clearthat only with the arrival of microcomputers that implementation of LANswere possible and necessary. (Schatt, 1987).

2.2. Components of a LAN

Each workstation of the LAN, which can be a microcomputer, a barcodereader or a word processor can work as an autonomous equipment, but theyare connected to a central controlling unit, through which they can communicate( exchange data, share software or hardware ) with other workstations ofthe network. Though each workstation can act independently, they are notcapable of controlling the activities of other stations of the network.To avoid corruption or collision of data during communication, severaltechniques like Career Sense Multiple Access/Collision Detection (CSMA/CD)and Career Sense Multiple Access/Collision Avoidance are used to controlthe transmission of data. Further information on these techniques willnot be given here since it lies outside the scope of this paper. Figure1 shows the basic components of a LAN (Collier, 1988).

• Communication medium: there is some kind of medium to connect allthe workstations and other equipment together.

• File server: a computer dedicated to providing shared access to amain storage device.

• Print server : a computer dedicated to providing shared printing facilities.

• Gateway : a computer providing access to other networks.

• Workstation: a user's computer or any other equipment.

2.6 Types of LANs

LANs can be divided in to two categories based on their topology andcommunication media. According to topology LANs can take several formsbut three core forms can be identified easily as follows:

• Star. Each workstation is connected to the control unit in the formof a star. Communication between two workstations has to be done throughthis central controller. A particular station which wants to communicatewith another station builds up a connection, through the central controllingcenter, with the destination. Once this connection is established datacan be communicated from one to the other station.

• Ring. This category has no central controller but devices are jointtogether in a form of a ring. Data has to pass some other workstationsto reach its destination. " A station wishing to trans-mit waits untilits turn and then places a data packet on to the ring. This circulatesaround until it reaches its destination where the node copies the datainto a local buffer. The packet then continues to circulate until arrivesback at its source. This then provides a form of acknowledgment." (Winfield,1984).

• Bus. This takes the form of a data highway connecting all equipmentto a linear communica-tion media. A transmission from any station can bereceived by any other station like in the ring type. Hence there is nosufficient data security in these types. " Obviously if all these devicesstarted transmitting at once there would be chaos, so only one device isallowed to 'talk' at any one time. A form of access control is enforcedto determine who can transmit next. The most commonly used medium accesscontrol is known as Career Sense Multiple Access with Collision Detection."(Winfield, 1988).

2.7 Communication Media

Based on the type of communication media used to connect the workstationsLANs can be divided into three groups.

• Twisted pair wires. This is the most common form of wiring and thecheapest. Consists of two identical insulated wires wrapped together ina double helix. Twisting the wires together reduces the noise - any noiseemanating from the environment or the communication medium, which is nota part of the message to be communicated.

• Coaxial cables. This is a copper conductor surrounded by one or morefoil or braided wire shields, each separated by the other by some kindof plastic insulator.

• Optical fibers. This is the latest form of communication medium whichconsists of thin strands of glass enclosed in an insulator. These are lightin weight, but the cost is still high. Needs expertise in installation,but the data security is very high, since any tapping of the lines canbe detected easily due to the disturbances of the light signals.

2.8 Advantages of LANs

LANs are used mainly for resource sharing. Expensive hardware like laserprinters and CD/ROM drives can be shared by several users when they areattached to a network. Further, purchasing a network version of softwarecuts the costs of purchasing them for each and every computer.

Central control of equipment and data provides easy administration,better data security and more flexibility in changing the system.

Instead of purchasing a multi-user system, the available equipment fromdifferent vendors can be connected together using a network.

3. APPLICATION OF LANS IN LIBRARIES

Although Local Area Networks have been in existence for some time, theiruse is fairly recent in the field of libraries. The initiative steps weretaken by the American and British libraries. By taking their applicationsas examples, we can make an attempt to adopt this interesting technologyin our libraries too. The following sections will describe how LANs canbe used in a library environment.

3.1 Housekeeping Applications

In several libraries LANs have been used to assist the housekeepingapplications or it would be more correct to say that test projects wereundertaken to experiment on this aspect. A good example is the Universityof Aston (UK) LAN installation project where they concentrated on acquisitions,cataloguing and circulation control. (Brindley, 1987).

• Acquisitions. The users of the library for e.g. the academic staffof the university depart-ments can directly send their book orders to theacquisitions department via the LAN, and also they can keep a track ofthe books received conveniently through the LAN. These orders could bedirected on-line to the book seller if a gateway is available to theirnetwork. Blackwell's PC ORDER system caters for this type of book ordering.Once a connection is established between the finance branch of the parentorganization and the library, a correct record of expenditure can be obtainedwithout delay, which will enable the proper utilization of funds.

• Cataloguing. The requirement of a union catalogue can be eliminatedwhen a LAN is avai-lable since each branch library can have their own cataloguesin site and provide access to other catalogues via the network. This savesthe time of the users by eliminating the requirement to visit each branchlibrary in search of books. Further, when cataloguing the material bookdetails can be obtained from the acquisitions department where most ofthe bibliographic details are available. The cataloguing staff will onlyhave to add what is not there.

• Circulation control. The facility of returning the books at any branchlibrary within the geographical coverage of the LAN could be provided inorder to save students time, but of course the books will have to be deliveredto the respective library at the end of the day. Checking details of delinquentborrowers could be easily traced when circulation data are attached toa network.

3.2 Educational Services

LANs can be utilized in the library for educational purposes too. AstonUniversity has made plans for two types of services. (Brindley, 1987).They were going to provide an on-line database advisory with trained stafffor users engaged in a remote database search and secondly they were havingplans to run tutorial classes in on-line searching simultaneously in differentlocations. In this manner there users will have a better understandingof the electronic media with which they have to interact in the library.Staff time and money will be saved by providing training for a larger groupof students simultaneously. Computer conferencing which uses several remotecomputers attached to a network to conduct a conference without the actualgathering of participants to a single venue, is another application ofLANs which could provide a sophisticated service for the future libraryusers. The LAN installation in the Department of Information, Universityof Strathclyde has been employed to carry out an experiment on computerconferencing and the author asserts that, despite the ergono-mic and technicalproblems, computer conferencing and electronic journal production haveconsi-derable potential and appeal (Baird, 1987).

3.3 Resource Sharing

Installing high cost hardware like CD/ROM drives and readers in a LANallows sharing of them by a multitude of library users. This in turn willreduce the cost of purchasing several of them for a single library. ThomasP. O'Neil Library of Boston College (USA) has installed Multiplatter whichis a CD/ROM Local Area Network designed by Silverplatter to allow multipleusers to access the same CD/ROM disc at the same time. (Grant, 1989). Wheresoftware is concerned, several copies have to be purchased if several computersare using them. But purchasing a network version of the software, (of courseat a higher price than a single version but lesser than several copies)tobe installed in the LAN makes things much easier. The principal reasonfor establishing the LAN at the R.H. Fogler Library of the University ofMaine, Ohio was to ease the burden of handling requests for software, whichincludes Dbase3 Plus, word processors, course specific discs etc. usedby the students. (Flower, 1988).

3.4 Office Administration

The library office could be connected to various other offices, forinstance personal, finance and welfare branches etc. To avoid wastage oftime used to obtain information manually from different branches, LANscan be employed to transfer data, with a certain amount of security, tothe library office. Using the concept of electronic mail library staffcould be contacted easily instead of calling for meetings, further electronicmail facility could be used to prepare news letters and memos to be circulatedamong the library and through a gateway among other libraries too. Howeverthe ASLIB/BLRDD LAN project says that this function was soon tailed off.(Copeland, 1986). It further says that NCC has established that everybodyshould have the discipline to check for the incoming mail for this to bea success. (Copeland, 1986).

4. CONSTRAINTS ENCOUNTERED IN APPLYING LANS IN THE LIBRARIES OF DEVELOPINGCOUNTRIES

We have been unable to reap the full benefits of LAN technology in ourlibraries, mainly because most of our libraries are not yet automated inits true sense. Automation is still limited to one or several microcomputersand a limited number of applications. Predominantly the application auto-matedis the library catalogue. In that also, a fully automated On-Line PublicAccess Catalogue is rare. Until computerization is in the full swing, orat least several of our library procedures are automated we cannot actuallyfeel the necessity of communication between the different workstationsin the library.

Secondly, the absence of qualified professionals in the field of libraryautomation, has contribu-ted immensely to this issue. It should be emphasizedhere the problems we encounter in training our librarians, especially providingthem with a training, so that they could be on par with their counter-partsfrom the developing countries. Hence the information of availability oftechnology does not reach our libraries adequately.

Thirdly, as a core cause of the two reasons shown above, the scarcityof financial resources could be pointed out. Procuring of electronic dataprocessing equipment, suitable software and establishing sophisticatedcommunication links which is essential for LAN applications, is impairedby the direction of national resources towards more basic need satisfaction.

5. SUMMARY

LANs can be defined as the interconnection of computers and peripheralswithin a limited geographical area, and they can be distinguished, basedon their topology and the communication media used to interconnect theequipment. Application of LANs in libraries were initiated in Americanand British libraries. Housekeeping applications, educational services,resource sharing, and office administration are the major areas in whichLANs can be applied in libraries. Yet, this technology is still not employedin the libraries of developing countries because of the computer applicationsare not yet wide spread to feel the necessity of networking, because ofthe lack of technical knowledge of the librarians and above all, becauseof the lack of financial resources to overcome the first to problems.

REFERENCES

Baird, Patricia M. & Borer, Beatrice. (June 1987). "An Experimentin Computer Conferencing Using a Local Area Network," Electronic Library,5 (3): 162-169.

Brindley, Lynn. (May 1987). "Planning for Library and Information ServicesOver a Campus Wide Network," Netlink, 3 (3): 4, 6-9.

Collier, Mel (ed.). (April 1988). "Telecommunications for InformationManagement and Transfer," Proceedings of the First International Conference,Leicester Polytechnic. London: Gower.

Copeland, Joyce. (March 86). "The ASLIB/BLRDD LAN Project," The ConclusionNetlink, 2 (2):

4-9.

Flower, Eric & Thulstrup, Lisa. (September 88). "Setting Up a PublicUse Local Area Network," Wilson Library Bulletin, 63 (1): 45-47.

Grant, Marilyn A. & John C. Stalker. (September 89). "The MuliplatterCD/ROM Network at Boston College. Laserdisc Professional 2 (5): 12-18.

Halsall, Fred. (1988). "Data Communication," In Computer Networksand OSI. 2nd ed. Wokingham: AddisonWesley.

Schatt, Stan. (1987). Understanding Local Area Networks. Indianapolis,Indiana: Howard W. Sams.

Winfield, Bob. (November 1985). "An Introduction to Local Networks,"Netlink,(1) 4-6.