Disk drive daze
Welcome to this month's episode in a continuing saga of life in computerdom's fast lane. If you haven't been following the story, here's a quick recap of what you've missed: In "Nightmare Mission," we explained our assignment, which was to develop a full-fledged aircraft simulation game in a very short amount of time. To complete this project on schedule, we had to use the fastest and best tools available, as well as some pretty wild techniques. We've been talking about these tools and techniques in order to save you, the advanced programmer, time -- your most valuable, and most expensive asset.
In "Nightmare Mission" and "Mission Accomplished," we covered the assembler, MAC/65, and the revolutionary debugging tools we used for the project. This month, we will talk about disk drives. Briefly, as a professional programmer, what sort of disk drive do you need? Which one is best? After all, there are numerous models available for use with the Atari.
First, let's group the available drives into two classes: slow and fast. The slow group includes the Atari 810, Percom, ATR-8000, and Rana. The fast group includes the Corvus hard disk, RAM-DISK, LE Systems drive, and (to a lesser extent) the Happy moditication to the Atari 810.
The fast group is four to eight times speedier than the slow group. Speed comes right out of your time, so think seriously before purchasing a slow drive. Consider how much time you spend waiting on the disk drive; you have to:
- wait for DOS to boot
- wait to load MAC/65 (or AMAC)
- wait to load your program
- wait to save your program
- wait for your object code and print file to be written to disk
- wait for the DOS menu
And so on and so on.
As owners of the RAMDISK discovered long ago, getting rid of such delays greatly increases productivity. That's why Atari recently purchased and installed a number of RAMDISKs for their in-house development labs. At the time, it was the speediest device available.
Ask yourself this question: in a typicai six-month game development cycle, how much of your valuable time is spent waiting on the disk? Multiply this by what you hope to earn per hour. Perhaps the added cost of a fast disk drive is not unjustified.
We'll cover the slow drives first, but bear in mind that we recommend these drives only if you cannot afford something faster.
To "begin by summarizing," our basic procedure is to stick with a product that has been around for awhile and has had its bugs worked out. Don't buy a brand new product and become the beta-test site for that new product's develoger! This applies to both slow and fast drives.
1. Atari 810. This product has been a never-ending slow-motion disaster for Atari from the beginning. First, it was designed without a data separator, a real no-no. This was eventually patched. Next, it was discovered that the RPM on the drive varied widely. Again, a fix was eventually developed. The interleave pattern was also incorrectly laid out; this was corrected in the "C" ROM. Finally, Atari switched mechanisms from MPI to Tandon; this was okay except for the fact that Tandons are very good at offcentering floppy disks. The solution? Only put in a floppy when the drive is spinning. Flip it off and on if you have to, but make sure that the motor is running before you insert a disk and close the door. (On the new 80-track drives from Nearly Anyone the act of inserting a disk kicks the motor on for two or three seconds, so the motor is running when you close the door. There is a very good reason for this; 80-track drives are extremely sensitive to proper centering. It would be nice if Atari, or Happy, added this feature into a new disk ROM.)
We hate to say it, but we cannot recommend even the new Atari 810's to professional programmers. There are less expensive, and far more reliable, alternatives on the market. If you are a beginner on the Atari, perhaps the 810 is a good thing for you; it is quite straightforward to hook up and use, especially compared to some of the alternatives. But if you have been around the Atari for awhile, the 810 is out: it wastes too much of your time and is too expensive.
2. Percom drive. For awhile, the Percom was considered the "drive of choice" among the slower drives. This is because at the time it was introduced anything was better than an 810! Once again, however, the user base has become a beta-test site. The horror story we have heard is that no matter how a disk performs during formatting on a Percom drive, the Percom will always tell the Atari that everything is okay. You could put a paper plate into the Percom, tell the drive to format, and the unit would tell the Atari that the plate was a perfectly good disk.
Replacement ROMs are available, however, if you push hard enough, and if someone who knows what's going on happens to be in Percom's office.
Finally, Percom corporate is quickly losing interest in the Atari, a point that was most evident during my last visit there.
My conclusion: Percom is a drive whose time has passed.
3. ATR-8000. We could rave about the ATR for the rest of this column, but there are other things to discuss. Very simply, we highly recommend this unit to nearly anyone who wants an Atari disk drive; the only exception would be someone who is completely unable to handle disk drive interconnections and drive selection.
This is a well-thought-out and well-executed unit. We took a look at the source code to the ROM and CP/M BIOS and knew in ten seconds that we had seen the work of a far better programmer than ourselves, one Russell Smith of BigBoard and Xerox 820 fame. The ATR-8000 has sheer class in terms of disk-handling power, far more than we have seen in any other system.
The base ATR-8000 is a fine disk controller and printer spooler, and if you ever want to upgrade the unit's memory you'll get CP/M-80 in the bargain. (CP/M is an operating system that gives you access to a huge library of practical software.)
We should note that we have an ATR-8000 (serial #4) and continue to use it and like it; we're writing this article using CP/M's "Wordstar" on the ATR-8000 with two eight-inch disks. Eight-inch disks can be used with the Atari 800 via MYDOS, which allows all 2002 sectors of a standard 8" to be accessed. That's 241K per disk. No more disk swapping!
The ATR has had its bugs, and we're up to revision 3.1 on the ROM, but most of the bugs seem to be out. Support has been outstanding. Summary: A great but.
4. Rana Elite. This is a brand new drive. It seemed to work quite well when I tried it out last week. However, remember that companies like Atari, Percom and SWP (ATR-8000) couldn't get it right the first time, or the second, or the third ... We think some bugs can reasonably be expected. Our advice would be to wait and see how it works out.
Also worthy of consideration is double density. Double density is a mixed blessing for you, the software developer. In many ways it is convenient. But Atari has never supported double density officially, and there are problems involved in its Operating System's dealings with 256-byte sectors. New DOS'S (like MYDOS, from SWP) solve a lot othese problems, but cannot be used with any copy-protected (or a lot of other software. Also, be very wary of AMAC/MEDIT with double density; real "Twilight Zone" stuff seems to happen occasionally with it. Our advice? Double density is fine for software development, but forget about it for a lot of other uses. An investment in MYDOS would do you well, however; this is the first DOS we have seen that lets you access the Percom standard DD/SD commands (supported by Percom and SWP) directly.
So much for the slow drives. Now let's talk about the faster alternatives.
1. Corvus hard disk. Sure, it costs over$2,000. But it's very fast and gives you a lot of storage. If you do quite a bit of software development, it will pay for itself quickly.
The smallest (5Mb) Corvus contains the equivalent of 59 single-density floppy diskettes in storage. The largest (20Mb) contains the equivalent of 192 floppies. Corvus also supports networking and multiple-Atari systems hooked to one drive. Software houses take note: you can run several Ataris off one Corvus at highspeed, and gain programmer productivity.
The only "problem" with the Corvus is that the operating system is customized for the machine. While the OS works correctly, you cannot use anything that is copy protected or anything with a custom DOS, like valFORTH. Other than that, we recommend the unit highly. We have one, love it, and use it for any software development we do on the Atari; these days we only use floppies for interchanging data with other systems.
2. RAMDISK (now called RAMPOWER-128). This unit is a fine, inexpensive alternative to the Corvus; it can be had for $200. The unit is a memory board, containing 128K, which plugs into the middle slot of the ATari; 92K is assigned to emulate a single-density drive. It does so at an incredibly fast speed; the RAMDISK is the fastest "disk drive" you can get for the Atari. It speeds up assembly times, loading the DOS menu, and so forth tremendously. However, the RAMDISK requires a special DOS, which makes it incompatible with a large amount of software. Keep in mind, for example, that you are not going to be able to sort your Visicalc spreadsheets with the RAMDISK; Visicalc is copy-protected.
Another major problem is that the RAMDISK loses its data when the Atari is turned off, or during a system crash. Because you can expect to crash many times during the development of your software, a RAMDISK may prove to be more frustrating than useful. However, if you are involved in an application in which you frequently re-assemble code, don't crash a lot, and can use the RAMDISK more than once per session, we highly recommend the unit.
3. LE Systems disk drive. Since we own part of LE Systems, we really should not do more than mention the name. This is a very expensive and fast floppy drive, suited only to software developers and those who need fast diskette duplication in massive quantities. A single drive unit starts at $1,150.
4. Happy 810. The Happy board is a real success story. Richard Adams, the brother of Scott Adams of Adventure International, designed a new board for the Atari 810 that makes it capable of a great number of things. To begin with, disk accesses on the Happy 810 are track-buffered, so you can get to data on the disk much more quickly. Also, the quirky bugs in the 810 are fixed in this version.
The speed of this unit is considerably faster than that of a plain 810. If you already have an 810, and want to make a minimal investment, making a Happy modification to your present drive would be an exciting and excellent idea.
Summary: This is a very good system.
Now for a brief look "on the horizon."
The Atari serial bus is the primary reason that the slow drives are slow. Recently, however, an interesting method for dealing with the serial bus has been receiving more and more attention. The new method involves clocking the bus from a slower frequency. This change enables more data to be transferred across the bus in less time; the typical speedup averages around four times the previous speed.
Happy's new Warp DOS seems to use this modification, although we cannot be sure of this. (Happy does not provide the source code to their system), and Percom's new hard disk for the Atari seems to be destined to use this system as well. Be forewarned, howvever: the system requires a custom DOS on the system end to replace the serial I/O drives in ROM. Note the different sound of the Warp DOS in operation: is it the serial bus being clocked at a different frequency?
Percom's hard disk is still up in the air. When we visited the company, there was a definite lack of interest in Atari; with the IBM PC taking over much of the market, Percom is putting most of its efforts in that direction. Consequently, the decision to produce the hard disk for the Atari has not been made, and is still tied up in office politics at the moment. We will see. Preliminary discussions with the designer of the prototype, though, indicate that the reclocked serial bus will be used, along with a new tree-structured DOS from OSS - if the product ever makes it out of the decision committee.
As software designers, we have been intensely aware of the Atari disk drive and its problems, and have tried many alternatives. That's why we have an ATR-8000, RAMDISK, LE Systems disk drive, and a Corvus; each of these has a special application in which it is the best unit available.
Unfortunately the RAMDISK and Corvus have problems in their operating systems that make them incompatible with much of the software on the market. There is a product that solves these problems, however. It's the Integrater board, and it makes the RAM- DISK and Corvus coexist with anyone's DOS. It even lets you start up directly from the Corvus, not from an 810 as with Corvus DOS. However, we are again in the position of highlighting a product that we helped design, so we shouldn't say anything more.
We hope you have enjoyed this discussion of disk drives. During the development of our aircraft simulation game, we started out using LE systems drives, and later switched to a Corvus; this was a major reason we completed the product on schedule.
Be sure to tune in next month when we cover a hot new topic: the secrets of bank selection.
The list below shows which of the disk drives we have recommended are available in a given price range:
$ 200-$ 300: RAMDISK or Happy disk drive modification
$ 300-$ 600: ATR-800 with five inch floppies
$ 600-$1000:ATR-8000 with eigh-inch floppies and MYDOS
$1000-$2000: LE Systems disk drive
$2000 and up: Corvus (5, 10, and 20 Mbyte units)
LIST OF MANUFACTURERS
(you cannot order directly from Atari)
Axlon Inc. (RAMDISK)
70 Daggett Dr.
San Jose, CA 95131
San Jose, CA 95050
P.O. Box 32331
San Jose, CA 95152
13010 Research #220
Austin, TX 78759
Percom Data Corp.
11220 Pagemill Road
Dallas, TX 7542311
21300 Superior St.
Chatsworth, CA 91311
SWP, Inc. (ATR-8000)
2500 E. Randol Mill Road, Ste. 125
Arlington, TX 76011
David and Sandy Small are proffessional programmers who work extensively with Atari computers and Atari-compatible peripherals and software to produce commercial software for the Ataris. In System Guide, they share discoveries, insights, experiences and secrets of professional programming that should be of interest to others at or near their level of practice. Questions or suggestions can be addressed to the Smalls care of ANTIC. Responses are not guaranteed, but may be made individually (if a self-addressed, stamped evelope is provided) or publicly in this department.