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Is Unix in accountants' future?

Its natural network connectivity and crash resistance make it an operating system to consider.

Most personal computers (PCs) run on the traditional disk operating system (MS-DOS), a decades-old program designed to handle only one computer and one application at a time. (For definitions of the technical terms used in this article, see the color-coded comments in the margins.) Thus, when users want to network their computers to share data and application programs, special networking software has to be loaded on top of DOS. While the networking software solves many of DOS's limitations, configuring a DOS-based network can be like building a skyscraper on a foundation designed for a summer cottage.

Enter Unix, a highly flexible operating system that can replace both DOS and network software, handling any mix of mainframes and stand-alone PCs or computers and terminals on a network. This article explores the advantages of Unix and helps accountants determine whether they should consider switching to this operating system.

It should be said up front that Unix probably is not the best candidate for a small accounting firm. A network with fewer than about 20 computers works reasonably well with DOS. And while Unix could do the job somewhat more effectively, its installation cost is much higher and therefore it is not as cost-effective. But for larger networks, especially those with many different kinds of computer and terminal configurations, Unix could be a boon--running the system faster and more reliably; in addition, such systems cost less than those based on DOS.


Unix was developed in the 1960s by a group of Bell Laboratories' software engineers dissatisfied with the limitations of mainframe operating systems. Their initial goal was to design a powerful operating system for themselves--not for the commercial marketplace. They wanted a system that, unlike existing proprietary operating systems, would not be tied to the hardware characteristics of any particular brand of computer.

Early versions of the PC could not handle large, powerful operating systems such as Unix. The older version of DOS, which was compact and fast but had limited functionality, was a good fit for the embryonic PCs. After the introduction of more powerful PCs, a compact version of Unix, called Xenix, was marketed to support multiple users on PCs. Xenix performed quite adequately but generally was shunned because it was difficult to use. After all, it was designed by and for engineers and scientists; user-friendliness was not a design consideration.

In the years since, however, Unix was reengineered and made more user-friendly. With the recent sale of Unix System Laboratory by AT&T to Novell, Inc., the network software specialist, and marketing efforts by dozens of Unix software developers, the system is poised to become a standard in many computing areas. It's already been adopted by most mainframe and some PC vendors. Moreover, the federal government's decision to make Unix its standard operating system has given it considerable impetus and credibility.

Should accountants consider switching to Unix? When weighing that decision, they should consider two principal factors:

1. The number of users that will be on the network at any one time. A network of Unix computers can handle more users than a network of DOS computers.

2. The type of software used. Unix shared processors can handle record-oriented software (accounting applications) more effectively than DOS networks can. Each type of application software makes a different demand on an operating system. For example, accounting software usually requires less computing power than productivity software, such as word processing, spreadsheets and graphics. Therefore, if the mix of applications includes heavy use of accounting programs, Unix again may be the system of choice.

A question that comes up early in any assessment of DOS and Unix is, How easy is it to switch from one system to the other? From both the user's and the computer technician's point of view the migration path form DOS to Unix is easy. For example, in most cases there is no need even to switch from DOS application software to software specifically written for Unix. To make migration easier, Unix developers incorporated in their software the ability to work with DOS (for a list of Unix vendors, see exhibit 1, page 74). Thus, if DOS is overlaid on Unix, most DOS-based programs--from word processing to spreadsheet and accounting products--work fine. In addition, making migration even easier, an increasing number of software vendors are preparing Unix versions of their products. For a list of accounting software vendors that offer Unix versions, see exhibit 2, page 78.

What are the advantages of Unix on a network? In brief, they are reliability, flexibility, speed and, in some cases, economy.

* Reliability. Because it has fewer technical limitations than DOS, applications running under Unix are more fault-tolerant. For the same reason, Unix offers enhanced data integrity. That's why Unix tends to be the system of choice in mission-critical applications such as point-of-sale and on-line order entry.

* Flexibility. In a simple Unix configuration, one Unix-based computer (called a host) can serve multiple "dumb" terminals. The Unix host also can double as a workstation; in other words it can serve the needs of the terminals or computers on the network and still be used to calculate, input or retrieve data. In a typical DOS-based network, on the other hand, the host computer (called a server in DOS terminology) cannot function as a workstation; it must be dedicated to administering the needs of the computers on the network. In addition, unlike the Unix setup, DOS network workstations all must be computers; none can be a terminal. In general, managing a Unix shared-processor system is a simpler process than managing a DOS-based network.

* Speed. Accounting programs and other record-oriented software run most effectively in a shared-processing environment; that's because accounting programs make minimal demands on a computer's ability to calculate, requiring instead that large volumes of data be retrieved and manipulated in relatively simple ways. Thus, a single CPU can accommodate large numbers of users simultaneously. In contrast, data retrieval and transmission are the primary network bottlenecks.

For example, if a terminal user on a Unix system directs the computer to print a listing of all locations exceeding budgeted sales by 10%, only that command must be transmitted to the computer. The remainder of the task is performed by the host computer at a high speed. On DOS networks, the server transmits the accounting program over the network to the workstation computer. The program then requests one or several records from the server and, on their receipt, selects the relevant records, formats the applicable portion of the report and transmits it back to the server, where it is placed in a print file. The program may continue to request, format and transmit more records for addition to the print file until all records have been processed, when the report can be printed by the server. All of the data are transmitted over communication channels at speeds far slower than the computer's internal speed. Thus, accounting tasks typically execute far faster on shared processors than on networks.

* Cost. In addition to processing efficiency, shared-processor systems (those using dumb terminals rather than computers) typically are 40% to 50% less costly than networked systems. While the initial license fees for each Unix software package may be somewhat higher than those for a comparable DOS program, the per-user license fee often is lower.


Exhibit 3, page 79, compares the costs of configuring four types of multiuser computing environments: a VM/386 DOS-based shared-processor system (see the sidebar titled "A Gaggle of Operating Systems," below), a Unix shared processor, a LANtastic DOS-based peer-to-peer network and a Novell DOS-based dedicated-server local area network (LAN). One table shows the costs of 10-user systems, while the other details the costs of 20-user systems.

The four multiuser computing environments' hardware and software configurations were selected to match typical computer environments as closely as possible. While they are subjectively based hardware and software mixes and there may be other solutions, the relative cost differences between these configurations are based on the assumption new hardware and software must be purchased. Prices were obtained from hardware and software vendors offering competitive prices. The accounting software used is representative of many high-quality PC-based products, and it includes general ledger, accounts payable, accounts receivable, inventory and payroll modules.

From least expensive to most expensive, respectively, the results are: VM-386, Unix, LANtastic and Novell's LAN. Obviously, cost is not the only factor when considering different connectivity solutions. Other, perhaps more salient, factors are the numner of anticipated users and the nature of computing tasks, which affect system performance.


From a productivity point of view, one of the biggest advantages of Unix is its ability to multitask--that is, do more than one computer job at a time. For example, many Unix installations run a communications program in the background that is capable of receiving faxes and other electronic messages even while the user is working on another computer application. Thus, while a fax is coming in, for instance, a user may direct the computer to calculate and print aging of accounts receivables, to recalculate a spreadsheet and to perform both tasks in background mode. Simultaneously, the operator may begin composing a client letter using word processing software.

Communications capabilities built in the Unix operating system permit any Unix system to serve any other system. Thus, a single Unix-based computer simultaneously can support several terminals and serve several other Unix computers. Users are not limited to a simple shared-processing environment; it's possible to configure any computing mix that is justified by business needs. In a typicalsetup, three Unix computers can be connected to several user terminals with one serving as a workstation. Since the three computers are networked, any user--whether working at a terminal or at a computer--can run tasks on any of the three computers. These computers and their users may be in one location or situated anywhere in the world.


Unix is no slug when it comes to the graphical user interface (GUI). GUI is rapidly becoming an essential element of all software. In a GUI setup, a user triggers icons with the click of a mouse or a keystroke instead of typing long commands. While the Macintosh was the first computer system to achieve a significant market presence with GUI, Microsoft's Windows, which runs on DOS, popularized the technology. In fact, one of Unix's vendors, the Santa Cruz Operation, advanced the Unix operating system with its Open Desktop (ODT) program, which uses GUI technology. As a fillip, ODT is capable of displaying several active DOS windows simultaneously on the user's screen, a capability not yet matched by Windows. While Unix currently cannot support Microsoft Windows applications, a compatible version is promised soon.

Picking the best connectivity solution for various computer and terminal mixes is no easy task. Exhibit 4, above, shows the best solutions considering the nature of the tasks involved and the number of anticipated users. To be sure, making the selection is subjective and reflects both processing power and cost. For small installations (those with 2 to 20 users), a multiuser DOS-based shared-processor system is clearly the best choice when accounting tasks dominate. When other tasks predominate or when there is a mix of accounting and CPU-intensive tasks, a DOS-based peer-to-peer network may perform best.

For medium-sized installations (those with 21 to 50 users), Unix shared processor is recommended for predominantly accounting environments, a DOS-based dedicated-server network may perform best when there is a mix of tasks and a DOS-based peer-to-peer network may work best when CPU-intensive tasks dominate.

Large installations (those with 51 to 200 users) may be well served by a Unix shared-processor system if accounting is the major application. A network of Unix shared processors is likely to perform better with a mix of accounting and CPU-intensive software. A dedicated-server network might perform best for high-intensity tasks.

Finally, for very large installations (those with over 200 users), a network of Unix shared processors is recommended under any circumstance.

DOS was designed to work effectively on what is now an aging computer architecture. It was made to fit the limited hardware of early PCs and consequently has limited functionality. While it likely will be used for years to come, most business users who want to exploit the capabilities of new generations of computer hardware can do so only by selecting faster, more flexible operating systems. While Unix may not be in the cards for all accounting offices now, it's prudent to examine the system for the future.
COPYRIGHT 1993 American Institute of CPA's
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1993, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

Article Details
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Title Annotation:includes related article on other operating systems
Author:Hunton, James E.
Publication:Journal of Accountancy
Date:Nov 1, 1993
Previous Article:Taming the wild client.
Next Article:Accounting for multiyear RRCs and sales and lease-backs of assets leased to other parties.

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