Meanwhile, Back at the Ranch...
    Welcome back. When last you visited I had just placed my order for the U1traSpeed+ OS, a replacement operating system for the XL/XE series from Computer Software Services. I figured since I was placing the order anyway, I might as well get some other items at the same time, such as a couple of extra SIO cables. My attitude is that you can never have too many. Why do I mention the lowly SIO cables? Have patience.
    After a wait of less than two weeks my order arrived intact. I can only attribute the short delay and the undamaged state of the package to the fact that Canada Customs must have had a trainee on the job that week; one who had not yet acquired the skills which make Customs agents much reviled by us ordinary folks.
    When I opened the package I was met with a large chunk of epoxy with two rows of pins protruding out one side (the US+ module), as well as a small double-throw toggle switch and a 16-pin chip, both of which were connected to the US+ by several wires. I grabbed the manual and immediately moved to the installation instructions. The instructions and accompanying diagrams were very clear and simple to follow. Fortunately for me, since my "hacker special" 800XL resides in a PC case, I was able to skip those steps which detail how to remove the motherboard from the case and go directly to Step 5. I removed the existing OS chip from the board (I love socketed chips) and plugged in the US+ module. One wire from the module connects to a chip near the cartridge port and the 16-pin chip included with the US+ gets piggybacked to a 16-pin chip on the motherboard. So I fired up the soldering iron and made all the necessary connections. Then I hit a minor glitch.
    The 16-pin chip has two wires attached to it which connect to two of the pins on the ANTIC chip. Normally, that would be no problem for me. However, the wires coming off the chip were too short and wouldn't reach all the way to the ANTIC. Seeing no quick and painless way around this, I grabbed a couple of lengths of scrap wire, removed the existing wires from the chip, and soldered two longer pieces (about three inches longer) in their place. The rest of the installation was a snap. I put everything back together, plugged it all in, powered up and put the US+ through its paces.

Testing... Testing...
    Since most of my familiarity with 8-bit machines lies with the original 800, I decided to first check the module in XL-FIX Plus mode. The XL-FIX Plus OS is a 400/800 OS clone; in other words, when this OS is selected your software thinks it's being run on an original 400 or 800. Two software packages I have which don't work with the XL/XE OS are Apple Panic (from Broderbund) and Story Machine (from Spinnaker Software). So I figured a good check of the compatibility of the XL-Fix Plus was to try these programs with it. Both of them worked great. Okay, I hear you saying, "Big deal. I can do the same thing with a translator disk, which I can download from just about anywhere for next to nothing." The advantage of this module over a translator disk is that the translator only works with disk-based software. Since Story Machine comes on a cartridge, it can't be run at all on an XL/XE. Unless you have a US+ module running in XLFIX Plus mode.
    To test the compatibility of the module in both standard XL/XE mode and in US+ mode, I ran the module through a battery of tests. The tests ranged from running simple, standard SpartaDOS and MyDOS commands to running software that only operates on an XL/XE. Throughout all this I was never able to discern any difference in function between the two operating systems.
    The US+ features a number of goodies beyond those found in the standard XL/XE operating system. These include reverse function of the OPTION key on booting (the computer will boot with BASIC disabled if you don't press OPTION), as well as the ability to toggle the screen display (some programs can speed up execution by as much as 30% with the screen turned off), lock the keyboard (if you have to leave it unattended), and toggle the status of internal BASIC. There's also a configuration menu you can use to reconfigure your floppy drives without physically having to play with the switch settings on the back of the drives.

On to the Next Activity!
    If you recall from last time, my main impetus for buying the US+ was its built-in RAMdisk handlers. I was planning on using that feature of the US+ to set up my RAMdisk as DRIVE 1 and run Infocom games from there, thus saving wear and tear on my Percom drive and speeding up disk access for the game in the process. Now that US+ was installed and running properly, I turned my attention to the purchase of a suitable memory upgrade for my XL.
    Part of my problem is that I'm not an XL/XE aficionado. I've owned 8-bit Atari computers for eleven years now, and for just slightly over nine of those years I owned the original 400/800 series. I can talk about memory upgrades for those machines but knew nothing about the various upgrades for the newer XL/XE machines. So I did what anyone with a modem would do in a situation like this: I starting perusing stuff online. I sent out an SOS on USENET and received back a lengthy reply from Jeff McWilliams about the various XL memory upgrades. And I downloaded a bunch of files and messages from both CompuServe and GEnie; anything which smelled like a memory upgrade was copied to my Atari for later viewing. This, as it turned out, was my undoing.

Sidetracked!
    Every so often I feel the need to clean out the filing cabinet in my computer room. Usually, that need is incurred when I can't stuff anything else into the files, and if I do remove a folder to add something I can't squeeze it back into the stupid drawer. So I remove all the folders from the cabinet and go through them, trashing stuff which is no longer of use or badly out of date. (Anyone want to know what my electric bill was in February 1987? Neither do I!) The problem with this exercise, however, is that it's easy to get sidetracked. I'll find some little scrap of paper buried at the bottom of an obscurely labelled file folder which will give me reason to pause, and the next thing I know the filing cabinet has been forgotten in a wave of nostalgia as I root through the room looking for related pieces of junk... uh... memorabilia.
    Well, I had just downloaded about 50 files, messages and programs, that needed to be filed. Much of the stuff I got, although interesting, was of no use to me in my current dilemma and was summarily removed from disk. A couple of files were very relevant and were saved on another disk for future reference. And then I got sidetracked.
    I came across a message I had captured from the Atari 8-bit newsgroup on USENET giving a brief description of a device called SIO2PC. SIO2PC is a combination hardware device/software utility that lets you to use an IBMPC compatible computer as a file server for your 8-bit Atari. In other words, you can copy your favorite (unprotected) Atari software to the PC and have it act just like an Atari compatible disk drive. Well, here I sit with three 8-bit Ataris, one disk drive, and a newly purchased 386 PC-clone. Needless to say, my search for a memory upgrade for my XL went on hold.

SIO2PC: Just the Facts, Please
    One of the few real drawbacks to the 8-bit Atari is the dearth of cheap methods of mass storage. To add a hard disk interface (such as the Black Box from Computer Software Services), controller card and drive you could easily spend as much as you might on a stripped down IBM clone. What Nick Kennedy, the author of SIO2PC, has done is taken advantage of the best of both worlds. SIO2PC allows you to use the IBM-compatible and its (relatively) cheap hard drives as a mass storage device for the greatest computers known to mankind, the 8-bit Atari. (See Alan Sharkis' in-depth review of SIO2PC elsewhere in this issue.)
    SIO2PC is shareware; the software end of things can be found online in a couple of places (more on that later). The ARCed distribution file contains a large number of files including the SIO2PC software (which runs on an IBM-compatible PC), numerous documentation files as well as instructions and schematics on how to assemble the hardware yourself. If you're not into reading schematics or kit assembly, you can order a pre-assembled SIO2PC from Nick. The hardware is really a very simple design; if you've got any skill at all with a soldering iron you won't find it too difficult.
    The interface connects the SIO port on the Atari to the serial port on the PC. The interface readily accomodates the differences between the two types of ports. I won't spend a lot of time here detailing those differences; Nick includes technical (but easy to understand) descriptions of how the hardware works within the documentation.
    Simply stated, the interface translates TTL logic signals generated by the Atari SIO ports into RS232 signals that are understood by the PC. To that end, the heart of the SIO2PC's circuit board is the Harris ICL232 IC, which translates TTL to RS232 and vice-versa. All the components for the interface (except the ICL232) are available at Radio Shack. The Harris chip is available from most large electronics parts suppliers. I managed to scrounge a spare one from one of our electronics technicians at work (I'll have to tell you about where I work sometime). The one other part not readily available in your local neighborhood is an Atari SIO cable. You will, of course, need the SIO cable to hook up the SIO2PC to your Atari. And wouldn't you know, as luck would have it, I had just ordered that spare SIO cable from CSS along with my US+!
    It took me about a week to put the hardware together. (Actually, it took me a week of lunch hours in the electronics shop at work.) Once I had the board completed, I soldered in the Atari and RS232 cables, assembled the whole works in a small plastic case, and nervously plugged it into the SIO port of my 130XE. Imagine the shock and surprise of discovering that I had not: (a) inserted the chips backwards into the sockets, (b) forgotten a critical jumper, and (c) created an impossible-to-detect solder bridge somewhere. In other words, it worked perfectly the first time I plugged it in. That may not seem like much of an accomplishment to you, but it sure was to me!



Playtime!
    Now that I had a working SIO2PC, it was time to put it to use. It seemed the most obvious choice for testing a gadget like this was a software package that makes heavy use of disk drives: like, an Infocom game!. Generating the Atari disk images on the PC is trivial- assuming your Atari and PC are in close proximity. Mine aren't. So, I hauled my 130XE, Percom drive, and an old TV up to the second floor of our house where the PC resides and set them up side-by-side. I then took my newly constructed SIO2PC and plugged it into both computers.
    Just to dispel any misconceptions, the Atari doesn't write directly to the PC's hard disk. Rather, the PC software takes a chunk of memory from the PC and sets that up as an Atari drive. As an example, let's suppose you wanted to copy a single-sided single-density disk over to the PC. The software then reserves 88K of memory on the PC and creates in that memory an image of a SS/SD Atari disk. When you use your favorite Atari DOS to format that disk, it formats the image in the PC's memory rather than the PC hard drive. Once you've copied all your files (or a boot disk) to an SIO2PC image, you must remember to save that image before you turn off the PC: since the image is only stored in memory, you'll lose it when you turn off the PC.
    When initially setting up the disk image on the PC, you have the option of choosing from single, enhanced, or double density in the standard configurations (single or double sided), or else define a customized disk image (up to 65535 sectors) to suit your tastes. I only wanted to copy the two sides of my Enchanter disk, so I created two disk images (each 720 single density sectors long), and called them Disk 2 and Disk 3. I then booted a sector copier from the Percom, which was still defined as Disk 1. Once I had copied both sides of the floppy to the SIO2PC images I turned off the Percom, renamed the SIO2PC image of side 1 as Disk 1 and the image of side 2 as Disk 2, and rebooted the computer. Once the Infocom shell program had loaded and I was prompted to flip the disk, I simply exchanged Disk 1 and Disk 2 with the software (in essence turning the image of side 2 into Disk 1) and hit RETURN on my Atari. I played the game for several hours (without solving it) before declaring the experiment a success.
    The staccato sound you get through the TV speaker as a disk is read is impressive. I used the RPM.COM routine on the SpartaDOS-X cartridge to measure the effective speed of the SIO2PC, and it comes out to somewhere around 810 RPM, almost three times faster than a physical floppy!
    I'm very impressed with SIO2PC. Nick Kennedy has done a marvelous job of creating a very elegant piece of workmanship. If you own an IBM-clone in addition to your Atari and are looking for ways to increase the storage capabilities of your 8-bit, then believe me you will want this thing. And for a shareware fee of $10 if you build the kit yourself, you can't beat it.
    You can get SIO2PC on most of the major online services, including GEnie (file number 5281 in Library 2), CompuServe (in Library 3; find the files using BRO S2PC*.*), and the Internet (from the atari.archive.umich.edu anonymous ftp site in directory /atari/8bit/Sio2pc).
    Next time: I look for a suitable memory upgrade. Gee, I said that last time, didn't I?
    Products Mentioned:
    UltraSpeed+ OS
    Computer Software Services
    
    About the author. Mike Jewison is an astronomer by training and a computer hacker by accident.