Which PC to buy in '93?

YOUR BOSS calls, says he needs a computer for his clinic, and wants to know what he should buy.

Your technician cousin asks you about a computer that can do things.

A lab supervisor wants your recommendation on whether to buy new or to upgrade.

All these people probably think that a computer will solve all their problems while making them efficient. They also think that buying a computer is like buying a refrigerator: Computers are all more or less the same; you buy one and forget about it until it breaks down, then you call in a repairman.

The first thing they should know is that a computer will not organize their lives; chaos and disorganization in an office will reflect itself as chaos and disorganization in the computer. They will lose files, enter the same data multiple times, and may risk losing months or even years of effort because of incomplete backups, poor training, and inadequate maintenance.

Computers require care and attention. Computer maintenance is a daily task for each user. A scheme is needed to organize subdirectories and file names. Users have to keep records of file names and contents, computer configurations, software modifications, and daily backups. Almost every software program has "bugs" that may affect the way the programs are used. There are also manuals and disks to be read and loose pieces of paper that update the manuals. Almost every year there's a new software version that corrects previous errors while bringing along new ones.

* Typical computer uses. To type and prepare documents, you use word processors. Calculations of data that are presented in tables are best done with either spreadsheets or statistical analyses software. Use word processors for storage and retrieval of small files and random thoughts; spreadsheets to store well-organized and not very large data sets; and databases for most information storage and retrieval purposes. Communications with other computers and electronic mail are accomplished using electronic mail software.

There is a wide range of graphics programs for charts and drawings. Each of these programs can be adapted to the specific needs of the individual, and each has different hardware requirements.

You can buy a PC from $200 to $20,000. More expensive models feature faster operations (referred to as MHz); a math coprocessor for mathematical calculations and drawings; a faster display driver to "draw" things on your monitor; bigger monitors that are easier on your eyes and make work easier; larger hard drives to store more information; more computer memory, which makes everything work faster; software with more features (which you may never use); and a wide range of accessories. The latter include input devices, such as scanners, video-adaptors, and digitizers to input shapes and graphics data, such as tissues and cells; storage/retrieval devices, such as CD disks with a large capacity for pictures; and output devices, such as printers, plotters, sound, and video.

Most people perform only word processing. Simple word processing can be done on a computer with two floppy drives and a monitor, which can be obtained secondhand for about $200. A slightly easier-to-use version, an XT model with a hard drive, costs $200 to $400 (no color). More sophisticated word processors demand more memory and computer speed. DOS-based word processors, spreadsheets, and many software packages can run quite well on an 80286 PC with 2 Mb RAM and a 40 Mb hard drive, available for under $500, sometimes with an EGA or VGA color monitor.

A 386SX/16 MHz with VGA monitor, 60-80 Mb hard drive, and 2 Mb RAM for about $700 is an excellent system for DOS and for Windows applications that you do not use frequently (Windows runs slowly). The next system adequate for most Windows applications is a 386/25 MHz or a 486SX. These systems sell for around $1,300 (with 100 Mb hard disk and 4 Mb RAM). I recommend a 486DX/66 MHz with a "Local Bus" (current standard is known as VESA) for graphics/calculation-intensive applications, such as large spreadsheets, statistics, pattern recognition, plots, and graphics with many drawings rather than only words. A 66 MHz computer is about twice as fast as a 33 MHz computer. A Local Bus allows the video card, and sometimes the disk-controller card, to operate at speeds that are close to the processor, usually 33 to 50 MHz or more. (Most non-local buses or motherboards operate at 8 to 16 MHz.) In addition, video cards optimized for Windows can display data 5 to 10 times faster than regular video cards. A fast Local Bus computer and fast video card may give you more than 20 times the speed of a 386/16 MHz computer.

* Software programs. Word processors and occasional graphics running under Windows 3.1 (Microsoft Corp., Redmond, Wash.) work on a fast 80286 PC with 2 Mb memory and a 40 Mb hard drive. However, this system is rarely enough for complex Windows applications because it is very slow and has insufficient storage. Modern software demands large storage space. Depending on features used, Windows 3.1 may require 5 to 10 Mb; a word processor under Windows such as Word for Windows 2.0 (Microsoft), 15 Mb; a spreadsheet such as Excel 4.0 (Microsoft), another 10+ Mb; a database, 5 to 15 Mb; and a utility program such as PCTools (Central Point Software, Inc., Beaverton, Ore.), 7+ Mb. Thus a basic installation under Windows with a word processor, a spreadsheet, a database, and a utility program to manage the computer will require over 60 Mb. You can manage with a smaller hard disk, but you'll have to use simpler software--often quite adequate for most tasks.

Communications programs do not take much space, but graphics programs can use all the space you've got. Statistical programs, such as SPSS (either DOS or Windows versions, SPSS Inc., Chicago, Ill.), require between 5 and 20 Mb. Programs to draw scientific curves, such as SigmaPlot 5.0 (Jandel Scientific, San Rafael, Calif.), require more than 3 Mb. Excellent comprehensive graphics programs for curves, drawings, presentation slides, and word charts, such as Freelance for Windows (Lotus Development Corp., Cambridge, Mass.), require at least 10 Mb. Designer 3.1 (Micrografx Inc., Richardson, Tex.), one of the best drawing programs--though not adequate for scientific plots or word charts--requires more than 4 Mb plus space for clip-art drawings. All graphics programs can take millions of bytes to store pictures or drawings that you can use to create other drawings. For example, Corel 3.0 (Corel Corp., Ottawa, Canada) comes in a compact disk with over 100 Mb of pictures and software.

Graphics-intensive applications, such as chromatography or cell recognition, benefit the most from the fastest processor available (486 in 1992, 586 in 1993) and fast display drivers. As a general rule, it is cheaper to buy a larger hard drive initially than to update later on. At this writing, the 200 Mb drives are the most cost-effective. You have other options, however. (The prices that follow in parentheses are for one drive/one disk). You can purchase either 20 Mb or 125 Mb removable optical floppy drives ($400/$30 and $1,500/$60, respectively)--perhaps too slow for software but fine for storing archival data that may have to be accessed on occasion; or 44/88-90 Mb removable disks ($700/$150).

Identify your current and foreseeable needs. Then buy the best configuration for those needs according to market prices. In general, your computer works faster with more RAM memory than with a faster processor. Get at least 4 Mb RAM. Disk-intensive applications such as databases benefit more from a faster drive and cache memory (memory used to speed up disk applications) than from a faster processor.

Faster processors cost more and require faster, more expensive components. Buy the largest hard drive that will accommodate all your software and data files and leave at least 10 Mb free. Programs need at least twice the amount of space of one file to operate because they create intermediate copies. You can often delete unneeded parts of software or use data compression programs, such as Stacker (Stac Electronics, Carlsbad, Calif.) and SuperStor (Addstor, Inc., Menlo Park, Calif.), to just about double your disk capacity.

Nobody likes to spend time switching floppy disks to make two or three backups each day (your usual minimum). Thus you should get a 120/250 Mb tape backup. You should make three backups every time you install software since installation is so time consuming. You also should make two to three backups every day as files are changed. It is usually sufficient to back up data, but often program control features get changed.

* Guidelines to select a PC. If your computer will be used exclusively to control one instrument, identify the smallest computer that will fit the job and get something slightly bigger to accommodate future improvements. I don't recommend Windows for those people who do only word processing. Instead, I suggest a word processor under DOS 5.0, such as Microsoft Word 5.0 or Word Perfect 5.1. An AT 286/12 MHz with 40 Mb drive, 2 Mb RAM, and monochrome monitor is sufficient, and costs about $600. If you want to standardize, purchase 386SX/16-25 MHz with 80-120 Mb hard drive and 4 Mb RAM, monochrome VGA for $900 to $1,200. You can save more than $100 on a lower-resolution VGA, primarily used to control other equipment.

If you need a mathematics coprocessor, it is less expensive to buy a 486 that has one than to buy a 386 and add the coprocessor. Don't buy the SX version, which is a DX model without the mathematics coprocessor. Math coprocessors are necessary whenever you run graphics-intensive or statistical applications, such as chromatography, pattern recognition software, or statistical analyses. You should have one computer in the laboratory dedicated to these purposes.

In general, computer hardware costs are small compared with personnel costs. Training and maintenance costs are often far greater than initial hardware costs. Waiting time can be very expensive. An inexpensive printer for $200 costs 3 cents a page but may take a minute to print one page, which comes to about 25 cents in labor. A laser printer may cost 8 cents a page but only 6 cents in labor.

Buy the faster computer for tasks that require frequent operator assistance to make decisions, such as manual peak integration and identification or pattern recognition. The cost of additional computer speed is compensated by labor savings.

* Upgrade or replace? Sometimes you have to decide whether to upgrade what you have or to entirely replace it. Upgrade if you have plenty of useful parts and the cost of the upgrade--parts and labor--is below the cost of a new PC. As a general rule, making a PC from scratch does not make sense.

RAM is sold in units of 256 K, 1 Mb, 4 Mb, 16 Mb, or 64 Mb (with increases by a factor of four). Most computers have four slots for memory on the board. If you purchase 4 Mb, you usually purchase 4 x 1 Mb chips. When you want to upgrade, you will have to discard the 4 x 1 Mb chips and buy other chips.

Determine your needs because memory prices drop on an annual basis. If you think that you will need more memory within 6 to 12 months, you will save money and time if you buy it now. For instrument control, 1-2 Mb is often enough. For mathematical calculations involving area integration (e.g., chromatography) or pattern recognition (e.g., hematology), you may need 8-16 Mb. It may be cheaper to buy one 16 Mb chip than 2 x 4 Mb chips now and get two more later down the road.

For technological reasons, it appears that the fastest 486 computers will be either the 50 MHz or the DX2/66 MHz (which is a 33 MHz working at 66 MHz internally and at 33 MHz for external communications). Faster 486s will not be made. The next generation will be the 586. When buying a 486, consider the following additional factors:

* The 486SX and several hybrid 486-386s manufactured by companies other than Intel do not include a math coprocessor.

* The 486DX includes a math coprocessor. (Most lab operations work faster with a math coprocessor, but computers used only for instrument control or administrative tasks often do not need one.)

* Many portable computers that use battery-saving features usually do not include a math coprocessor.

* It is wise to buy a Local Bus feature that allows both a video card and a disk controller to run as fast as the processor rather than the usual 8 or 16 MHz speed.

* Video cards change specifications every few months, so brand comparisons can be misleading if a "new" card is compared with the competition's "old" card. Look for the actual number of items processed, measured as either "WinMarks" for Windows speed, "text" or "Bitbits" for general graphics. A top video card rates more than 10,000,000 WinMarks compared with less than 1,000,000 for an old VGA card.

* Some disk drives can read and write 2.88 Mb rather than just 1.44 Mb.

* Some companies allow their BIOS (the basic instructions recorded on a chip to start the computer) to be upgraded via software. Although this is a useful feature, you may never need it, particularly when using a PC to control instruments. If you upgrade the BIOS, be aware that the instrument control software may not work.

* Some companies provide an extra slot to insert a future upgrade of the main processor. Because this feature is becoming standard, its cost is difficult to quantify.

* Consider including either an internal or external tape backup if you generate huge amounts of data and need backup.

* Consider a CD-ROM drive if you plan to use software or training material on CDs.

Many companies that market instruments to laboratories include a PC with the sale. Generally it is a good brand, but the lab pays more for it than comparable products on the market, particularly in the case of portable PCs and printers. Although the company may imply that its software will only work with its PC, such is rarely the case.

The author is a senior scientist in the clinical nutrition unit at University Hospital, Boston University Medical Center, Boston, Mass.