Classic Computer Magazine Archive CREATIVE COMPUTING VOL. 11, NO. 10 / OCTOBER 1985 / PAGE 70

Local area networks; tying computers together: the productivity connection. Russ Lockwood.

Around the turn of the decade, the corporate world discovered the microcomputer. Emerging from a tradition of mainframe and minicomputer terminals, executives found that pairing this small, relatively inexpensive, stand-alone unit with a spreadsheet offered ease of use, convenience, and increased individual productivity. With the entry of venerable IBM into the market, they accelerated into the Information Age, expanding into word processing, databases, business graphics, and other software to boost the capabilities of their one-stop, desktop information centers.

However, information must be disseminated to be truly effective. A typical business report often requires the skills and data of many people. The problem is to connect these separate microcomputers together to share data. The solution proves to be the local area network (LAN).

An LAN is a collection of microcomputers and peripherals linked by a short-range, common communications path. It allows users to share files such as databases and spreadsheets and provides a cost effective method for sharing expensive peripherals such as hard disk drives and laser printers.

Boundaries of the LAN

Do not confuse LANs with multi-user systems. The distinction between the two is small, yet important. An LAN is a system that ties otherwise independent microcomputers together. A multiuser system uses a time-sharing scheme to link terminals. Once the exclusive province of mainframes and minicomputers, multiuser systems are fast being challenged by powerful microcomputers like the IBM PC AT, Tandy Model 16, and AT&T3B2 series.

In general, if a microcomputer (or workstation if you prefer mainframe terminology) executes programs with its own processor and in its own memory, it is part of an LAN. If a workstation uses only the processor and memory of a central computer, it is part of a multiuser system. In some cases, a microcomputer-based multiuser system can be more effective than an LAN. However, for overall flexibility, expandability, and performance, an LAN is preferable.

Private Branch Exchange (PBX) systems are often considered and used as LANs. They fit, albeit rather loosely, within the category of linking individual and independent processors and memory. However, PBXs are primarily phone systems that connect microcomputers via modems (see the May 1985 Creative Computing for an indepth look at modems).

Wiring costs are extremely low, for you are transmitting over phone wires that are already in place. It is terrific for voice mail--integrating voice with data--but sharing the interoffice telephone system with data-sending computers can cause problems. Reliability is the most critical factor in evaluating PBXs.

Transmission speed, even using special modems, is limited to around 64,000 bits per second (bps), although some PBXs allow up to 128,000 bps. By comparison, the Apple Talk LAN operates at 230,400 bps, and the IBM PC Network, at 2 million bps. The 3Com Ethernet series offers speeds up to 10 million bps. While the cost of installing a PBX is lower, an LAN generally offers superior performance.

The Year of the LAN

LANs are not a new development. Xerox developed Ethernet at its Palo Alto Research Center back in 1976 to link several single-user minicomputers. However, the early LANs were quite similar to the early microcomputers: expensive, technically complicated, and requiring specialists to install and maintain. As the concept and the systems evolved, LANs became less expensive, yet higher in quality; more flexible, yet easier to install; and more sophisticated, yet easier to use. And like the microcomputer market in general, LANs attracted the eye of industry giants.

Indeed, 1985 may well be remembered as the year of the LAN. Industry giants IBM and Apple, as well as aspiring giant AT&T, all introduced LANs this year. Meanwhile, the smaller, established LAN manufacturers are scrambling to make their systems compatible, especially with the IBM network.

Local area networking is still a fragmented field. According to Dataquest, a San Jose, CA, market research company, industry leaders 3Com and Corvus installed roughly 10,000 LANs each, connecting a total of about 150,000 microcomputers. Apple's much ballyhooed Apple Talk LAN, the Macintosh Office, is installed at 2500 sites linking approximately 7500 Macintoshes. Networked microcomputers, however, still represent a small percentage of the machines sold.

The lack of a true industry standard is keeping many corporations from installing LANs. However, several analysts are predicting that the entrance of IBM into the market with its IBM PC Network Program may help set an LAN standard just as IBM set an operating system standard with PC/MS-DOS.

Already, Microsoft has entered into agreements with 3Com and Ungermann-Bass that will make those two companies' products (EtherSeries and Net/One, respectively) compatible with the IBM PC Network.

Whether IBM sets a standard and dominates the market remains to be seen, but analysts do agree that the LAN market will experience tremendous growth. A Yankee Group study shows that 625,000 microcomputers were connected to one type of LAN or another in 1984. The company expects that number to grow to 7.7 million networked microcomputers in 1988. Dataquest predicts a 46% compounded annual growth rate for LANs and LAN products through 1988, which translates into roughly 7.1 million networked microcomputers.

Hardware LANmarks

In its simplest form, an LAN is a group of microcomputers or workstations connected by cables. The more sophisticated LANs include various peripherals, interconnections with other networks, and a host of specialized components. However, no matter how complex the LAN, it boils down to individual components performing specialized functions.

The term "server" is defined as a component that handles special tasks within an LAN. It can be either a microcomputer or a peripheral, and it caters to all the requests of the networked microcomputers.

A disk server is a hard disk drive that is available to all networked computers. Usually, it is partitioned so that each computer accesses a particular private storage area. For all intents and purposes, it acts like an extra disk drive.

Some disk servers allow certain storage areas, dubbed public volumes, to be accessed by all workstations. In many cases, access to a particular file is limited to one workstation at a time. Depending on the LAN and the sensitivity of the data, changing the information in public volumes can be performed by any network user or be restricted to authorized network supervisors.

A file server is a more sophisticated version of a disk server. The hardware remains much the same, except greater software control over the hard disk drive allows access to data by file name. The partitions may or may not be emplaced, and the software provides several layers of security to protect the integrity of the data. In more sophisticated LANs, two people at two separate workstations can access a file and update it interactively.

Disk and file servers can be either dedicated or non-dedicated. If dedicated, the server processes only network operations and is not used as a workstation. A non-dedicated server performs double duty: it processes network operations and offers the option of running applications like any other networked microcomputer. Since non-dedicated servers divide their microprocessing power with stand-alone applications, dedicated servers often perform network operations faster than non-dedicated servers.

Within a network, disk and file servers can be designated as centralized or distributed. A centralized server is like a mainframe setup: all cables, connections, and data lead directly to a single server. It generally handles many network requests simultaneously and offers increased security. The idsadvantage of a centralized server is that if it becomes inoperative, the entire LAN goes down. Also, should the hard disk drive be damaged without adequate backup, all files could be irretrievably lost.

Distributed servers make all networked microcomputers equal, allowing all workstations to function as disk or file servers. This type of network is more expensive, since each workstation is equipped with a server, however, loss of one server and workstation will not affect the rest of the network. Security may pose a greater problem in a distributed server network than in a centralized server network.

Key Components: Boards

Just about every LAN requires you to insert an expansion board inside your computer to connect to the network. The boards usually contain a microprocessor, a signal converter, and a network interface controller. In the case of the IBM PC Network, the Network Adapters include an Intel 80188 microprocessor, Intel 82586 communications controller with modem, and Sytek serial interface controller.

The major exception to this expansion board requirement is the Macintosh on the AppleTalk network. Cables hook directly into the serial port because Apple has included networking circuitry inside the Macintosh.

Some companies, notably The Software Link of Atlanta, GA, avoid boards by using the RS-232C port for networking communications. Its LANlink program places the logic that normally resides on the controller chip onto a disk and also in the server. The advantage, according to Gary Robertson, director of marketing for The Software Link, is shorter installation time and lower overall cost.

The "local" in LAN refers to geography. Unlike nationwide computer networks like Tymnet and Telenet, LANs are usually limited to a single building. However, networking distance can be stretched to connect to outside networks with various hardware components.

A repeater acts like an amplifier and retransmits signals down the line. A bridge also retransmits signals, but usually between two different LANs. A router is a more sophisticated signal retransmitter that takes longer to forward signals between LANs than a bridge, but determines where messages should be forwarded. A gateway connects networks that use different protocols and may also connect an LAN to a mainframe.

Media: The Aisles of LAN

In LAN lingo, the electronic pathways connecting the various components are called media. In most cases, the connections are made with twisted-pair wires or coaxial cable, although fiber optic technology is quickly encroaching on the traditional media, and infrared technology looms on the horizon.

Twisted-pair wires consist of two insulated and shielded copper wires wrapped around each other. They are much like telephone wires and carry both voice and data. Indeed, both AT&T and Apple use twisted-pair wiring for their respective StarLAN and AppleTalk LANs. This flexible wire is by far the easiest to install, move, and expand, and it costs much less than coaxial cable and fiber optics.

On the negative side, signals traveling through twisted-pair wires lose power with distance unless extended with repeaters. Signals maintain a reliable speed of up to only 1 million bps. Twisted-pair wiring is extremely susceptible to electromagnetic interference and radio frequency interference (EMI/RFI) and offers poor security unless installed within a specially protected (expensive) enclosure.

Coaxial cables are the same as those used by cable TV stations. An outer insulating layer surrounds a metallic sheath. Inside the sheath is an inner insulating layer that encloses a thick central wire. The sheath and central wire share the same curvature, hence the term coaxial cable.

Three types of coaxial cable are used: trunk, a high quality cable for long stretches; feeder, to come close to the microcomputer; and drop, the smallest and most flexible cable that hooks directly to the microcomputer. You might think of the cables as roads--trunks are county highways, feeders are residential roads, and drop cables are driveways. Any medium beyond the gateway is an interstate.

Coaxial cable costs more than twisted pair wiring, and installation is more difficult because of the relative inflexibility of the cable. However, coaxial cables allow signals to travel faster, provide greater resistance to EMI/RFI noise than twisted pair wiring, and can carry video signals in addition to data and voice. The IBM PC Network uses coaxial cable.

Fiber optics is a relatively new, yet promising technology for LAN media. While a twisted pair wire or coaxial cable LAN sends signals by shooting electrons along a wire, a fiber optic system changes electrical signals into pulses of light and transmits them along hair-thin lengths of glass.

AT&T, ITT, Corning Glass, GTE, and NEC all manufacture optical fibers. In essence, the manufacturing process involves withdrawing hair-thin fibers from a glass tube. A gas torch deposits various chemicals on the glass and alters the refractive index of the glass.

The resulting fiber consists of two parts: the core, which passes the light pulses (signals) along, and the cladding, an opaque layer surrounding the core, which prevents light from escaping.

The Telecommunications Products Division of Corning Glass Works displays a working fiber optic LAN at its Corning, NY, office. It connects about 30 DEC Rainbows and a handful of IBM PCs to a DEC VAX superminicomputer. It is not a commercial product, but a showpiece of fiber optic technology. See the sidebar for a sample fiber optic connection.

On a more practical front, companies like Ungermann-Bass of Santa Clara, CA; Siecor Fiberlan of Research Triangle Park, NC; Fibercom of Roanoke, VA; and Codenoll Technology of Yonkers, NY, are already marketing fiber optic components for LANs.

Unfortunately, fiber optics is such a new technology, the industry lacks a broad base of skilled technicians. The cost is much higher than either twisted pair of coaxial systems and optical fibers are generally point to point connections; they cannot be tapped into easily for expansion. Also, the capacity of a fiber optic system, at 3 billion bits per second, versus the transmission speed of a microcomputer, even at 19,200 bits per second, represents quite a bit of overkill.

On the other hand, fiber optic systems are virtually immune to EMI/RFI and serve best in a heavy industrial area. The speed of light is certainly a fast enough transmission speed, and signals remain strong over long distances. Optical fibers are thin and lightweight, provide high data security, and pose no fire hazard.

Still in its infancy, infrared technology may help end the cable clutter of LANs. Several companies are exploring this area. Becos Industries of Campbell, CA, has developed an infrared communications device that attaches to an RS-232 port. It permits up to 99 channels of simultaneous communication at a data transmission speed of 400,000 bps.

American Band Stand

In the LAN world, the debate over whether to use baseband or broadband media is as hot as whether Lite Beer from Miller is less filling or tastes great--and as important. To the end user, it matters little. To the technical wizards, it matters a lot.

In baseband, one signal occupies the transmission media, and all terminals receive the same frequency. In broadband, signals can be divided into different frequencies, so many signals can occupy the medium at once. Like a radio, you can tune into a specific frequency, in effect creating a mini-network within an LAN. While broadband requires more electronics, it also can transmit TV, security, and other signals.

The drawback is that broadband cables are usually unidirectional, which means you need two cables to connect each station. New techniques are being developed to use half the frequencies for outgoing signals and the other half for incoming signals. Of course, that reduces the number of frequencies available by half--and then some because you need a buffer between the outgoing and incoming signals.

Who will win the debate? It is hard to say. Baseband certainly deserves respect, especially because Apple and AT&T have thrown their weight behind it. But wait a minute. IBM has chosen broadband, and if any company has the potential to break down walls and influence the market, it is Big Blue. For now, the game remains tied.

The Lay of the LAN

The scheme of creating an LAN and linking all the components together is called a topology. In theory, three main topologies dominate the market: bus, star, and ring. However, in practice, some manufacturers are fusing two topologies together to increase performance.

The bus network (sometimes called a tree network) consists of a single cable with taps for each microcomputer and peripheral. As a result, expanding the system is exceptionally easy, and the LAN will continue to operate if a single workstation malfunctions. However, bus networks often require a minimum distance between taps to reduce noise. Furthermore, tracking down a suspected fault in the system means checking every component of the system, or at least every component between a pair of repeaters. A bus network is excellent for sending short messages.

A star network uses point-to-point paths between a centralized host and the microcomputers and peripherals. All communications funnel through the central host. Maintenance can be simple or catastrophic. If one of the workstations malfunctions, you can pinpoint trouble immediately. If the central host malfunctions, the entire LAN shuts down. A star network is good for shared databases, but is not well suited for simple message switching.

A ring network consists of a circle of microcomputers and peripherals. It offers a faster response time than the other two topologies, and all stations constantly monitor the system. While a ring network offers greater equipment reliability, loss of one station may shut down the entire system. It is difficult to service and even more difficult to expand.

Enter the Fast LANe

LAN manufacturers employ a variety of schemes to place signals into the LAN and keep them from getting crossed. For most people, the method does not matter as much as the performance, but subtle differences in the schemes affect performance.

Polling is most often used in the star topology. The master network server waits for a signal from one of the microcomputers and then processes it.

Reservation, another favorite for star topologies, permits the transmission of signals at preselected times. Note that reservations occur several times per second. If another signal has exceeded its reserved time, that signal has priority on the network and any new signals must wait for an opening.

Slotted ring, used in ring topologies, passes a master signal (called a frame) from station to station. This frame, a series of bit patterns, marks the beginning and end of a signal and holds its destination. The transmitting microcomputer grabs the frame, inserts a signal, and sends it into the network. The signal goes to its destination, where the receiving station replaces the signal with a verification code and sends the frame back to transmitting microcomputer. The transmitting microcomputer takes the code out, marks the frame empty, and passes the frame into the LAN, where the next station grabs it and the process begins anew. This is a most inefficient system, for it requires much reading and replacing.

A more efficient scheme is token passing. The token is much like the frame. However, once grabbed, the trasmitting microcomputer alters the bit patterns to indicate that a signal is coming and then inserts the signal. The receiving station takes out the signal and recreates the original bit patterns. The token then goes to the next microcomputer.

Contention schemes, popular on bus topologies and some star topologies, come in three types and follow the idea of first come, first served. Common Sense Multiple Access (CSMA) lets a microcomputer determine whether any other station is transmitting, and if not, starts transmitting itself. This scheme carries a real danger of two stations starting to transmit simultaneously, especially on an LAN with a long bus.

CSMA/Carrier Avoidance attempts to minimize crossing signals. When two stations do transmit at the same time, the signals are sent garbled, but the senders retransmit when they fail to receive an acknowledgement that the signal was received perfectly. The Apple Talk LAN uses this scheme.

CSMA/Collision Detection also attempts to minimize crossing signals. When two stations do transmit at the same time, they both immediately stop transmitting and wait a variable lenght of time before retransmitting. The Ethernet, AT&T StarLAN, and IBM PC Network LANs use this scheme.

Standard Woes

As we said before, the LAN market lacks a true standard. In a strict sense, this is not exactly true, for at least three organizations have put forward loose definitions of LAN standards. Please note than because two protocols are blessed by the same organization they cannot necessarily communicate with each other; witness the rush by LAN manufacturers to make their LANs compatible with the IBM PC Network.

The International Standards Organization (ISO) offers the Open System Interconnection (OSI) reference model. It consists of seven layers, each of which controls a particular LAN function or feature. The first three layers are concerned with data transmission and routing; the last three are geared to user applications; and the fourth provides an interface between them. The layers are:

* Physical: governs the electrical connections of the hardware.

* Datalink: activates, monitors, and controls hardware.

* Network: establishes, maintains, and terminates connections; routes and addresses data.

* Transport: interfaces between first and last three layers; selects data routes.

* Session: controls paths between stations; controls identification and authorization functions.

* Presentation: formats, encodes, decodes, and otherwise prepares data for top (application) layer.

* Applications: the programs with which the user works: database, word processing, electronic mail, etc.

Meanwhile, the Consultative committee for International Telephone and Telegraph (CCITT) adopted the X.25 protocol in 1976. The X.25 standardizes data transmission and routing (the physical, datalink, and network equivalents of the ISO/OSI standards).

In addition, the Institute of Electrical and Electronics Engineers (IEEE) is forming another set of standards, including 802.4, an emerging industrial networking standard, and 802.5, a token-ring standard.

To LAN or Not to LAN

So every business with a few computers needs an LAN, right? Wrong.

Remember that the main advantage of an LAN is the ability to share expensive peripheral devices and files. If you do not intend to purchase laser printers and huge capacity hard disk drives, you have a good reason not to purchase an LAN. If your files do not require constant updating by many different people, and LAN is probably unnecessary.

do alternatives that satisfy longrange computing needs exist? Most definitely.

If your company owns a mainframe or minicomputer with excess capacity, then hooking the microcomputer, either as a dumb terminal or as a smart terminal that can create, upload, and download data, may prove to be a solution.

In the same vein, if you own a small business and need to hook up only a few workstations, a multiuser microcomputer may be the best solution.

Telecommunications, that is, hooking up a modem to your computer and sending information over the telephone lines, can also be an inexpensive and fairly reliable solution. This can be the previously mentioned PBX system or a common, off-site network. Here at Creative Computing, columnists and some of our editors upload their files to CompuServe or MCI Mail. At our end, we download, edit, and format the file to our specifications--rather a neat and instantaneous solution.

Finally, if your computers and software are compatible, you can simply pass around the disks holding the relevant files.

However, sometimes none of these alternatives provides the flexibility, ease, and speed of an LAN. Perhaps you really do need to share a laser printer, hard disk drive, and files. And perhaps the electronic mail feature itself is worth its weight in gold. The array of choices available staggers the imagination, and the technical pitches by silver-tongued salesmen require the wisdom of Solomon to decipher and understand. The task is formidable, but not insurmountable, providing you consider certain aspects of LANs.


Of course, your networking requirements will differ from others. The nice thing about LANs is that they can be custom designed to fit your needs. However, before settling on a particular LAN, consider the following general areas.

An LAN must provide good performance for each type of application you intend to run. If you cannot run a database program correctly or efficiently, then an LAN is practically worthless.

It should include the option of installing gateways to outside networks, especially the System Network Architecture (SNA) "standard" from IBM. Althourhg it is not an LAN standard, more and more LANs are hooking up to SNA networks.

Make sure the LAN supports security functions. This is not meant to keep 15-year-old hackers out as much as to protect the integrity of the data from accidental change or erasure by LAN users. You also may want to allow only cetain people access to personnel and payroll files.

The network should be easy to maintain. This is probably the biggest bugaboo of LANs to date and a nebulous topic at best. Different topologies require different maintenance strategies. Different companies possess differing views about maintenance. New technologies offer more risk (and again) than old technologies. In general, when installing the LAN in the first place, provide quick identification of each component and easy access to them with adequate space around them. Let the idea that the system should be kept up and running and the down time minimal be your guiding light.

As a corollary to easy maintenance, an LAN should be easy to expand. This means both adding microcomputers and peripherals and replacing and upgrading those already on the network.

Finally, the LAN must be available. Instead of releasing a complete network at once, companies are marketing bits and pieces. IBM released the networking hardware and then made us wait for the software. The AT&T StarLAN network will not be close to completion before mid-1986. You have a choice between waiting for a "new," improved LAN and purchasing and gaining the benefits of an "old" LAN immediately.

These general guidelines are fine for the strategic overview, but certain, specific recommendations will help your tactical decisions.

Electronic mail is a feature that should be on every LAN. The ease and speed of sending an electronic memo without wasting paper and time should not be overlooked. You should be able to store, edit, discard, forward, reply, and send multiple copies of electronic messages to recognizable addresses. An added feature is the ability to set up an interactive link to send real time messages (similar to telephoning a person). These messages are not stored, but are good for coordinating activities.

An efficient and capacious print spooler is a must for those sharing a printer. In many LANs, print spooling means one person sends output to the common printer and the rest are denied access and forced to transmit output at a later time. Sitting around waiting for the printer to become available is neither pleasant nor efficient. In such situations, a print spooler with a large buffer is a must.

Make sure the LAN you buy supports the microcomputers you intend to connect. The IBN PC Network is designed to support the IBM PC family. If you own Compaqs, Zeniths, Leading Edges, or other compatibles, the PC Network may not support your clone. On the other hand, a non-IBM LAN will generally support IBM compatibles as if they were IBM PCs.

This idea extends to linking different brands of microcomputers. Although all can share the network, dividing the hard disk into separate sections for dissimilar operating systems (as most LANs do) limits file compatibility. In effect, only like computers can use like files. This gets back to the discussion of disk sharing versus file sharing. Sharing just a disk decreases cost, but sharing files increase productivity and communication.

Centram Systems West of Berkeley, CA, claims its Tops LAN accommodates Macintoshes; IBM PCs and compatibles; Tandy TRS-80 Modesl 4, 12, 16, and 2000; CP/M; and Unix machines to share files. If so, and if Tops does so speedily, Centram may be offering the solution to the incompatibility problem.

Finally, consider the installation itself. For example, what are you going to do with all those cables? Leaving them lying around turns the office into Dr. Frankenstein's laboratory--not to mention creating an accident-prone area and a fire hazard. Do you place them in unaesthetic cable trays or hide them in a dropped ceiling? Or a raised floor? How about a cellular floor with a spiderweb of conduits under the floor--expensive, but it provides maximum coverage. As you can see, just creating the layout of an LAN, the cables, microcomputers, and peripherals, requires careful planning. Even then, you must allow for expansion.


So much for the hardware considerations. However, like a microcomputer, an LAN is but a lifeless interconnection of equipment and calbes without networking software. Unlike a microcomputer, your choice of network software is limited to the network you purhcase. This condition may not last long after IBM releases its Network Program and Microsoft releases its highly compatible MS Network Software.

In general, the software should be simple enough for a novice to negotiate without becoming tedious for the experienced user. It should include a logical environment in which operations are executed in a straightforward manner. Working within certain parameters, it should be interactive enough to let you know where you are, what you are doing, and how to accomplish a particular task.

Often, vendors advertise that their software operates with all types of microcomputers and operating systems. While this is technically true, be sure to verify this claim with an actual demonstration. Quite often, the conversion utilities supplied with the system are dreadfully slow, which can cause a bottleneck in LAN operation.

Pricing LANguage

The cost of an LAN varies with the number of stations. The more microcomputers you add to an LAN, the lower the cost per station.

In general, media costs will be a few cents per foot of twisted-pair wire, a dollar or two per foot for coaxial cable, and roughly $10 per foot for fiber optics. Equipment connections will run $5, $40, and $50, respectively. Network adapter expansion boards run in the $500 to $700 range.

The other parts of the system are less uniform in price. Perhaps the best way to start pricing LANs is to look at a configuration for a specified number of stations--four, eight, twelve, or whatever you intend to install.

Installation costs are often shadowy figures. With most vendors quoting on uninstalled systems, your final total can be substantially higher than the sum of the components. And finding out about hidden costs--for example, using tefloncoated cable to comply with the codes--can be close to impossible.

fortunately, some vendors are trying to help potential customers evaluate their costs. Quadram offers first-time prospective purchasers a free program called Selectnet, which asks pertinent questions about your proposed LAN. It then goes on to pitch Quadram's offerings, but the sales spiel is subordinate to the educationsl value. Ungermann-Bass fields an entire network design team that provides prospective customers with quotations on newtwork design and material needs.

Unlike a microcomputer applications program, which carries one price because it operates on one machine, networking versions carry different price structures. So far, two pricing policies are emerging as winners: per window and per user.

Per widow means that the software allows a maximum number of windows to be opened on the network at once. Sorcium/IUS charges for the program itself and then charges a variable fee for a master network software manager. For example, $395 allows up to four windows on the system, while $595 lets you open eight windows. A single user could open all windows at one station, or, could close one or two to allow another user on.

Per user means that the software price is related to the number of stations. For example, MultiMate charges $595 for one user to use its word processor on an LAN, $1195 for two users, and $295 per user thereafter. Cosmos charges $950 for one user, $1495 for up to four users, $2995 for up to 10 users, and $4995 for up to 32 users of its Revelation detabase management systems.

Charting New LANs

With all those LANs available, and an even greater number of LAN vendors, it is a buyer's market. The LAN Comparison Chart accompanying this article was taken from PC Communications, a three-volume montly updated reference service available from Data Decisions, 20 Brace Rd., Cherry Hill, NJ 08034, (609) 429-7100.

The best way to obtain information from manufacturers and vendors is to write directly to the vice president of marketing, mention you read about their product in Creative, and request an information kit. In the case of Quadram, you may also want to ask for the free program Selectnet. The more information you have at your fingertips, the more prepared you will be to select the LAN that best fits your needs.


Buying and installing an LAN represents a significant investment in both time and money, especially when you consider the cost of training people to use it. However, that is only one part of the process. You must evaluate your needs, assess future growth, consider the size and cost, and devise an overall plan. Once you figure out what you want your LAN to do, you start the research phase and investigate the plethora of products, multitude of manufacturers, and variety of vendors.

The task is formidable, but not insurmountable. Networked microcomputers improve the flow of information, save money on peripherals, and propel us into a new era of the Information Age. Networks are the brave new world of office communications, and the productivity riches waiting in the promised LANd more than offset the effort it takes to get there.