THE XL BOSS

ALLEN MACROWARE
P.O. Box 2205
Redondo Beach, CA 90278
800XL $79.95 1200XL $89.95

by Matthew J.W. Ratcliff

The XL BOSS (hereafter called "the BOSS") is a replacement for the Operating System ROM (Read Only Memory), which is designed to put you in control of your 800XL or 1200XL computer. This microcircuit converts your XL to a Revision B Operating System (OS) compatible machine.

This OS is found in Atari 400/800 machines less than three years old. It was, quite frankly, bug free. In the two and a half years I used my old Atari 400, I never found a bug of any sort. But, as many of you know, the XL OS has caused a lot of problems in software incompatibilities.

Many "illegal" operating system routine entry points for the Revision B OS have been documented in publications since Atari computers first hit the market. Software vendors quickly picked up on these, using them in programs sold to the Atari community. Now such software as Text Wizard, LJK's Letter Perfect (before revision 6.0), Megafont, Synassembler and many others can run with the BOSS.

There is a great deal of excellent public domain software which also required the Translator, until now. The BOSS even takes care of "compiled" BASIC programs (those compilers seem to break all the rules).

The Translator vs. the BOSS.

Using the Translator disk, you can run these programs on a 1200XL or 800XL. There is one major drawback with this converter program: it does not recover from SYSTEM RESET properly. Pressing RESET with the Translator installed almost always results in a system coldstart or computer lockup. When running game programs, this is usually no big deal. However, in applications software such as assemblers and word processors, an inadvertent RESET can wipe out hours of work.

Custom console key functions.

Not only does the BOSS recover properly from RESET, but it gives you some powerful options. Press and hold the OPTION key at power-up to enable XL BASIC (800XL only). This is just the opposite of the XL OS. If a cartridge is installed at power-up, it will automatically be given control of the system. By pressing the SELECT key during power-up, you enable the RAM OS. SELECT and OPTION enable the RAM OS and XL BASIC. This gives you the 4K of free RAM from $C000 to $CFFF. This RAM OS won't crash as the Translator does when SYSTEM RESET is pressed.

The BOSS also protects any software you may have stashed in the extra 4K. If you have an application program assembled to this address, it can be loaded from an AUTORUN.SYS file when the computer is powered up, while pressing SELECT. Since you probably don't have any applications software for this extra RAM, Allen Macroware provides Macromon, a powerful machine language monitor. Its functions will be outlined below.

Another unique feature of the BOSS is that it allows you to coldstart the system without turning off the power. This can be done by pressing and holding START, then pressing RESET You will hear a beep, as if you were going to load a tape. Press RETURN to boot a tape or press RESET again to perform the system coldstart (hitting OPTION and/or SELECT, as desired).

This feature will keep Macromon - or whatever program you may have in this extra 4K - intact. If you've booted up in the ROM OS and decide you need Macromon, just press RESET while holding SELECT. You will be in the RAM OS and may execute a binary load from DOS or MacroDOS (see below).

If Macromon is already installed (or any program with entry point $C000), press and hold OPTION and SELECT, then hit RESET This warmstart will send control to the program beginning at $C000, yet keep all your lower RAM program space intact.

The "console key" coldstart is not only handy, it's easy on the microcircuits. The chips in your computer are subjected to an inevitable power surge when the machine is turned on. If a computer is going to die, it will almost always happen when power is first applied. The custom coldstart feature minimizes this effect when you wish to reboot the system with a new DOS or application program. In a nutshell, the BOSS is a hacker's dream!

Why buy?

If you aren't the hacking type, this is still a valuable XL enhancement. Aside from fixing incompatibilities in software, it gives you additional buffer space when using disk-based applications software where every byte counts (Letter Perfect, Text Wizard, VisiCalc and others).

Using cartridge-based software, however, this is not the case. Cartridge software does not look for RAM above its own address space. The BOSS can be used in many other ways from BASIC and assembler/editor cartridges. I think the 4K extra RAM alone is worth the price of the BOSS.

Free software.

Allen Macroware provides Macromon and MacroDOS on disk with your purchase of the BOSS. Macromon is a machine language monitor that loads into the RAMbased system above the cartridge space. Its commands are as follows:

d	-	Display memory.
g	-	GOTO address. No return (RTS) is expected.
j	-	jump to address, with return expected (RTS - control returned to Macromon).
s	-	Split the screen, displaying two different sections of memory at the same time.
p	-	Print the screen on your printer.
.	-	Convert decimal number to hexadecimal.
$	-	Convert hexadecimal number to decimal.
f	-	Find string of data in memory.
c	-	Change bytes of memory.
v	-	Verify memory; compare sections of the memory and display differences in the split screen mode above.
m	-	Move a block of memory.
r	-	Read specified disk sectors into memory (single and double density supported).
w	-	Write memory to disk.

With Macromon, you can customize your RAMbased OS before running your application software. The manual documents such modifications as converting the CTRL-ARROW keys to the normal key operation. The math symbols can then be accessed from the SHIFT key, and the formerly-shifted characters are retrieved with the CTRL key.

MacroDOS, written by Jerry Allen, comes with your BOSS, as well. This mini DOS remains resident in RAM at all times. You can freely switch from your cartridge to MacroDOS and back ... without affecting the program in memory.

MacroDOS was published in Compute!, in the June and July 1984 issues. It supports all DOS functions except: write DOS files and file/disk copy. It's quite handy, as is Macromon. I only wish that Macromon would display memory with disassembly.

Installation.

The manual is accurate and provides helpful drawings to guide you in disassembling your XL computer and replacing the OS ROM. It starts with several cautions. First, you are advised not to attempt this revision until after your computer is out of warranty (in ninety days). Such a modification will void it.

Second, if you aren't the do-it-yourself type, you should seek the assistance of a knowledgeable friend or an Atari service center. If you're handy with your screwdriver and patiently follow the instructions, you shouldn't have any problems. It will take a bit more than the advertised ten minutes to install ... I read the instructions twice before starting, and it still took me half an hour, from start to finish (and I'm an electrical engineer).

The point is: proceed with great care and attention to detail. You only want to do this once. I have one caveat for you at this point. In the 800XL instructions, you are advised to "pry the side of the case outward" to lift out the joystick port connectors.

I found that absolutely no prying is necessary-and should not be done, or you risk breaking the case. When you've removed all the screws that hold the mother board in place, gently lift up the left front corner. As you bring the PC board forward and to the left, all the connectors and switches at the rear should pull free. At this point, continuing to pull forward and to the left will free the joystick connectors with no prying at all.

Does the BOSS pay?

I had no trouble following the directions, and the BOSS worked perfectly for me on the first try. I've already written handy machine language utilities to stash away in that "completely safe" RAM above the cartridge space. I used to do this with the Translator, but the time-consuming double boot procedure and fragile RAMbased OS were not worth the trouble.

In the past three weeks of using the BOSS, I have yet to lock up my machine (an hourly occurrence with the Translator). The BOSS is permanent relief from the Translator blues... I highly recommend it.