Classic Computer Magazine Archive COMPUTE! ISSUE 54 / NOVEMBER 1984 / PAGE 151


Bill Wilkinson

Comparing Printers

After disk drives, probably the most frequently purchased peripheral for personal computer systems is a printer. But buying a printer is a lot harder than buying a disk drive. Usually your choice of drives is limited to the computer manufacturer's own unit plus a few produced by third-party companies. And despite some slight differences, they all deliver similar performance.

But printers are another story. There are hundreds of printers on the market for personal computers. Most of them can be made to work with your Atari. And they vary widely in terms of price, performance, features, and compatibility.

One of the main differences between printers is their printing speed. Usually this is measured in characters per second, abbreviated cps. By comparing the speed ratings, you can decide whether a certain printer is fast enough for your applications. But recently I discovered how misleading those speed ratings can sometimes be. It all started when those of us at Optimized Systems Software (OSS) began looking around for a new printer.

To begin, let me tell you that we have a rather unique requirement for a printer: We needed a good, fast, reliable printer which we could hook up to any of several computers. And, of course, it had to be compatible with all our software: several languages, four different operating systems, and a couple of word processors.

It is also time for a bit of history. For the last couple of years, our mainstay printer has been a venerable DEC LA-120 Decwriter. This is actually a printing terminal (remember, from the days of mainframe timesharing?) which operates via a serial RS-232-C connection at 120 cps. As reliable as this beast has proven to be, it has a few problems: Its print quality is marginal at best, without even descenders on lowercase letters; because it uses a serial instead of the more standard parallel interface, much software simply will not work with it; although it is rated at 120 cps, it is actually capable of only about 105 to 110 cps when printing typical documents.

At the time, the only other printers we had (or had significant experience with) were a Diablo daisywheel (also serial, at 30 cps), an Atari 825 (rated at 60 cps), and a C. Itoh Prowriter (rated at 120 cps). All had performed adequately (or, in the case of the Prowriter, more than adequately), but all were too slow for our purposes.

And, of course, software compatibility was another big issue. Our primary problem in the past had been that some of our computers transmitted a linefeed after a carriage return (for example, the CP/M based machines), while others (our Atari computers) did not. We were well aware, also, that more problems would be coming as we acquired more software and wanted more capabilities.

Instantaneous Vs. Continuous Speed

For the sake of compatibility then, the first printer that came to mind was the Epson MX-80. Why? Simply because it is used on so many machines with so much software. Yet we immediately rejected the MX-80. Rated at only 80 cps, it is simply way too slow for our applications.

So we started looking for a fast printer which would be largely compatible with the MX-80. To make a long story short, we bought an Epson FX-100, a wide-carriage version of the FX-80. Imagine our surprise when this printer, rated at 160 cps, was only marginally faster than the Prowriter and actually slower than the Decwriter!

It turns out that with few exceptions, the printer speeds published by manufacturers and often faithfully reported by magazines are the maximum instantaneous speeds of which a machine is capable. This instantaneous speed rarely correlates to the actual number of lines a printer will produce in a minute.

What's more, even those companies which do admit that speed ratings are maximum values employ other claims to suggest that their printer is faster than the competition. For example, many claim that because their printers are bidirectional or logic-seeking, they are faster than the old-fashioned machines which print in only one direction (unidirectional).

Let me describe how the FX-100, for example, prints a typical program listing. First, it receives and prints a line (say, 50 characters), moving the print head from left to right, stopping at the end of the line. Then, it receives the command to print the next line (say, 70 characters). It moves the print head to the seventieth column, stops, advances the paper to the next line, and prints backward from right to left. If the next line is indented (mine often are), it goes through the same sequence of stopping, moving the head, and advancing the paper once again.

But stopping, starting, moving paper, and starting again all take time. A lot of time compared to the actual printing time. Printers like the Prowriter, on the other hand, contain an internal buffer which they use intelligently. After printing a 50-character line, it checks to see where the right end of the next line needs to be and automatically continues to move the head to that position. One stop-and-start sequence eliminated. The results? See for yourself in the following chart, which records the time it took for three different printers to print the same moderate-length program listing:

PrinterRated Speed (cps)Time RequiredApprox. Actual Speed (cps)
Dewriter1206 min 30 secs110
Prowriter1207 min 45 secs90
FX-1001607 min 30 secs95

Oh, yes. Did I forget to mention that the Decwriter has no logic-seeking and prints unidirectionally only? That's a lot of stopping and starting. Sometimes raw power can accomplish what "logic" can't.

Throughput: True Speed

Well, I would like to report that we ran out and bought 30 or 40 different printers and tested them, too, just so I could bring you a full comparison chart. But our budget at OSS won't stretch that far.

I did, however, go to several dealers and informally time the speed of various printers. Since I had a couple of reference points (the speeds of the Prowriter and FX-100), it wasn't too hard to get a fair idea of true throughput figures: the printing speeds they could actually sustain.

Then I discovered another trick used by a few manufacturers. Many printers are capable of two or three (or more) character widths or fonts (typically 10, 12, and 17 characters per inch). It seems to me that at least a few printers are rated only for their smallest (and hardest to read) fonts.

Luckily we had an understanding dealer who allowed us to "trade up" our FX-100. And what printer did we then buy? Actually, we ended up buying two.

Because of our need for a printer capable of using the vast library of MX-80-compatible software, we got an Epson MX-100 (simply a wide-carriage MX-80). We have been very happy with it, though I am sure any of several MX-80-compatible printers would have done as well. True, the MX-80 is slow. But its throughput rate seems to be around 50 to 60 cps, which is respectable compared to its rated speed.

Because we needed speed, though, we disregarded MX-80 compatibility for our other new printer, an Okidata 2350 (the model number seems to reflect its retail price). It is rated at over 300 cps and surprised us by performing our little speed test in 1 minute 55 seconds, for a throughput rate of over 360 cps. However, sometimes it gets too hot while printing long listings and stops to wait for the head to cool off. Even so, it probably has a throughput rate of 300 cps or more.

So, did you learn anything from our experiences? I sincerely hope so.

When shopping for a printer, ask to see a demonstration of its speed. Many printers perform better with uniform-length lines (such as those produced by a word processor), so ask to see a program listing also. And make your own time trials.

Judge the print quality for yourself. Ask about replacement ribbon costs. (We found one printer that worked only with carbon ribbons. $$$$! But if you need good print quality, it might be worth it.)

Above all, be certain a particular printer is compatible with your computer and software. Few things are worse than saving $50 on a printer only to find out you have to spend another $100 because your current word processor isn't compatible with your new printer.

Of Memory And Machines

We've received a few letters recently on seemingly different subjects, but which all relate to what is obviously some confusion and uncertainty about the Atari XL computers. Let's address these letters and, at the same time, shed some light on the workings of these little gems.

First, Jacqueline Patton of San Antonio, Texas, asks whether she is "stuck with a problem computer [1200XL] and an unreliable disk drive [Atari 1050]." We'll discuss the 1200XL's compatibility problems in a moment. First, a few words about the 1050.

I have not personally observed the 1050 to be any more or less reliable than any other drive on the market. Disk drives, in general, tend to be like automobiles: Sometimes you get one which goes 100,000 miles with no maintenance, and sometimes you get a lemon, but most often you get one which will last a reasonable time with reasonable care and regular checkups. This is not surprising: Disk drives and cars are both mechanical nightmares, subject to extremely close manufacturing tolerances and acute material stresses.

If the 1050 has a problem, it may be simply that it cannot read all of the more strangely protected software disks that are flooding the market. There are antipiracy measures in use today that try the limits of many drives and their controllers. Yet most programs will load fine on any good Atari-compatible drive, including the 1050.

My objections to the 1050 are centered around only one point: Although every other Atari-compatible drive manufacturer has complied with the Percom-standard double-density format (derived in turn from Atari's defunct double-density 815 drive), only Atari chose to be different. Further, Atari's method gives you a maximum of 128K bytes per disk. The others get 18OK bytes. There is no excuse for this. It results from Atari's typical blindness when it comes to outside vendors.

All this does not mean the 1050 is no good. It just means that, on a bytes per dollar basis, it is overpriced.

Use Your Options

Another letter, from Shahid Ahmal of London, England, was actually a complaint to OSS about the fact that some programs (including our disk-based MAC/65) would not load and run properly on his 800XL. The problem is that these programs require you to remove the BASIC cartridge before booting up—impossible on the 800XL and 600XL, since the BASIC "cartridge" is built into the newer computers as a standard feature. His solution was to write a program which switched off the built-in BASIC, changed RAMTOP, and closed and reopened the screen driver.

Whew! I am impressed. Doing all that in the proper order is not easy. But there really is a much simpler way.

This discussion applies only to disks containing programs which do not use Atari BASIC. Obviously, such things as assemblers, compilers, and utility programs fit this category. Not so obviously, many game disks will not run if Atari BASIC is present. In any case, if you own an 800XL (or, I assume, a 600XL with expanded memory), and the directions for a disk or program tell you to remove your BASIC cartridge, try this:

Turn on power to all devices except the computer. Insert the disk you wish to boot. Push and hold down the OPTION button. Turn on the computer's power. When the disk starts to load, you can release the OPTION button.

This has the effect of disabling the built-in BASIC. Atari's manuals tell you all this. But they don't emphasize enough that you should try this with any disk/program if it otherwise doesn't work. And they don't tell you about the OPTION button when used with the Translator Disk. "What's that?" Glad you asked…

I have mentioned the Atari Translator Disks before in this column, but only part of what I'll add is repetition.

If you own an Atari 1200XL, 800XL, or expanded 600 XL with a disk drive, run—do not walk—to your nearest Atari users' group and purchase (usually for about $10) the pair of Atari Translator Disks. (You may still be able to get them from Atari directly.)

The instructions tell you to boot the version A disk first, wait for it to give you a message, insert your otherwise unbootable disk, and push the SELECT key. If that doesn't work, you are supposed to try the version B disk. (Both disks actually load an old Atari 800-style operating system into your XL machine's memory, thus hopefully assuring compatibility with programs that rely on the older operating system.)

What the instructions don't say is that you may also need to hold down the OPTION button. Why? Because otherwise, good old Atari BASIC is still there, messing up the memory address space.

Six Ways To Boot

There are, then, no less than six ways to try booting a disk on an XL machine: with or without holding down the OPTION button alone or in combination with either of the two Translator Disks. This sounds like a real pain, but once you find the method that works with a given disk, you can write it down for future reference.

I should note that all of these methods still result in compatibility with only about 97 percent of all software (85 percent of heavily protected software). Is there anything you can do if your favorite piece of software won't boot using any of these methods? Yes, two things.

First, you can write, phone, telex, or otherwise cajole and threaten the software manufacturer. I have said before, and I am sure I will go hoarse saying again, that I believe the responsibility for the lack of compatibility does not rest with Atari. No other manufacturer has ever produced a series of computers with as many changes and improvements as the XL line and yet maintained as much compatibility as has Atari.

Second, you can try one of the commercial translator programs. I am aware of two at this time: XL BOSS from Allen Macroware and XL FIX from Computer Software Services. I have used neither, so I cannot comment on them. However, I recommend that to avoid unnecessary expense you should certainly seek verification from these manufacturers that the particular software package you want to use will work correctly with their product.

And More Memory

The commercial translator programs do have one interesting bonus: They give your XL computer an extra 4K of memory. Let's see why.

The original Atari 400 and 800 computers had a 10K operating system and a 2K input/output space. Since the maximum RAM they supported was 48K, that left 4K unused in the total address space of 64K (unless you bought a third-party RAM board—such as those from Mosaic—which placed RAM in this unused space). The empty 4K was located at address $C000 (49152), just above the normal 48K RAM.

When the XL computers arrived, they sported more graphics modes, device downloaders, parallel bus support, self- diagnostics, and more, all of which pushed the size of the operating system up to 14K. Guess where Atari got the extra 4K from? Yep. No more "unused" space.

However, the commercial translators effectively emulate the original 10K operating system, leaving that 4K free again. But since an XL machine has 64K of RAM, the unused space becomes free RAM. If you are using a cartridge-based program (even the built-in Atari BASIC), this isn't a real big help. The 4K of RAM is still at address $C000, above the cartridge address space. You could install machine language routines here, use it as a buffer for disk I/O or player/missile graphics, or even use it for any graphics screen up to the size of that of GRAPHICS 7. But the average beginner will have a hard time using this space.

On the other hand, programs which don't use a cartridge don't have this restriction. For example, if you use one of these translators to load VisiCalc into an XL machine, you'll gain 4K of valuable spreadsheet space. Try it sometime. It's easy.

And one more comment before we pause until next month: Since the Atari Translator Disks work much like the commercial translators, it may just be possible to modify them and gain the same 4K of RAM. I have not had the time to investigate this, but if any COMPUTE! readers discover anything in this regard, we'd be happy to hear about it.