SpartaDOS Construction Set / US Doubler

Reviewed by John S Davison


Issue 32

Mar/Apr 88

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Double the density .. twice the speed .. worth the price?

ICD/Frontier Software

ICD are now producing some superb products for the 8-bit user, and the two reviewed here can only enhance their reputation further. The first is SpartaDOS, a replacement for Atari DOS which can be used on any 8-bit disk system. Better still, you can use it with its companion ICD product, the US Doubler, a hardware modification to add sparkling performance to your old 1050 disk drive. They are marketed in the UK by Frontier Software, who sell them for 29.95 each or, as reviewed here, in a special combined package for a very reasonable 49.95.

SpartaDOS is an advanced Disk Operating System for use on Atari 8-bit machines. In fact, it's a whole family of DOS programs bundled together in a package known as the SpartaDOS Construction Set. Its name is derived from the way you can build a system disk containing a version of SpartaDOS appropriate to your purposes and hardware configuration.

The package includes two 5.25" disks containing all the software, a comprehensive 161 page instruction manual, plus a 36 page supplement covering SpartaDOS V3.2, the latest version. The combined package also contains the US Doubler chip set.


The first disk contains four different versions of SpartaDOS V1.1 plus its command/utility files. These may be used with any 8-bit machine having 24K or more of memory. They're not directly compatible with Atari DOS 2.0/2.5, but the powerful copy utility provided can convert files from Atari DOS to SpartaDOS format and vice-versa. The four versions include the standard DOS with and without US Doubler high speed support and two cut down versions for use simply as game loaders or with AUTORUN.SYS files and cartridges.

Side B of the disk contains a working sample of the SpartaDOS binary file loader menu. Included with it are a set of seven really good public domain games, and three spectacular graphics demonstration programs a nice bonus.

The second disk contains SpartaDOS V3.2 and two different flavours of V2.3. These versions will only run on XL/XE machines with 64K or more, and have a built-in Atari DOS 2.012.5 handler, making them directly compatible with Atari DOS files.

V3.2 is the latest version, including support for ICD's R-Time 8 realtime clock cartridge, BASIC XE, and hard disks amongst other things. The only difference between the two V2.3's is that at boot-up one gives priority to any installed cartridge software, while the other gives priority to SpartaDOS. Between them, all these different versions should cover virtually any requirement you just have to decide which one is most relevant to your needs.


SpartaDOS provides you with vastly improved facilities in a number of different areas. Firstly, it gives additional features not found in Atari DOS such as use of volume labels, sub-directories (like ST folders), time and date stamping of files, command files, batch files, and keyboard buffering. It's got 45 extra commands over and above the equivalents of Atari DOS menu items. And if you still feel SpartaDOS is missing something, the command file facility allows you to expand the system by writing your own commands.

Secondly, it improves on facilities provided in Atari DOS with such features as handling up to 8 disk drives, expanded capacity directories, locking at disk level as well as file level, and an excellent way of tagging files for copying as a batch instead of handling each one individually a great time saver.

Thirdly, it provides support for virtually all types of disk drives in single (90K), 1050 enhanced (127K), true double density (180K), and even hard disks via the Supra hard disk interface. It handles RAMdisks too, and not only on the 130XE. When using BASIC on any XL/XE it will use the 8K of RAM under the BASIC ROM as a small RAMdisk.

Finally, it complements ICD's US Doubler hardware modification for the 1050 disk drive, giving true double density capability (180K per side) and a spectacular increase in speed.

Incredibly, even with all these additional facilities it gives you MORE free memory for BASIC programs than Atari DOS! This wizardry is achieved by holding some of the code in the memory under the OS ROM. How about that for efficient use of resources!


SpartaDOS is essentially a command driven DOS, and in use it reminded me of IBM PC-DOS. If you don't like using commands then you can invoke the SpartaDOS menu function. This is worlds away from the simple Atari DOS menu, but it can make things easier for you.

You construct a SpartaDOS system disk by initialising it with the appropriate density and sector skew, and choosing the version of SpartaDOS you want to use. Sector skew determines how the sectors are physically mapped out onto a disk track, and the US Doubler requires a different skew from standard. US Doubler skewed disks will still work on an unmodified 1050, but slower than usual.


The US Doubler itself looks most unexciting, but its effect is anything but! It consists of just two chips which you fit onto the 1050's circuit board, replacing the ones already there. In most cases you just unplug the old chips and insert the new ones however, Atari produced drives with two different types of chips, so if you have one of the less common types you also have to unsolder and resolder two jumper cables as part of the installation process.

The most difficult part of the exercise is disassembling the drive to get to the board and reassembling it afterwards, for which you need nimble fingers. ICD provide excellent instructions, so most people should be able manage it without too much hassle. The whole job took me under an hour, but I didn't have any soldering to do. Once the chips are installed SpartaDOS can take advantage of them straight away.

In practice, the US Doubler and SpartaDOS worked together flawlessly, happily transferring data back and forth between disks of different densities and between Atari DOS and SpartaDOS disks. The US Doubler handled the switching between densities completely transparently you don't even know it's happening!

The US Doubler really makes itself felt when used with the high speed versions of SpartaDOS. The normal pedestrian beep-beep-beep of 1050 I/O is replaced with a frenzied torrent of beepery as the data screams to or from the 1050 at three times normal speed. It's truly amazing!


You'll hardly recognise your 8-bit machine when used with these two products. It really will take on a new lease of life, gaining facilities, operating convenience and a performance sparkle you never thought possible. And they'll probably save you time and money too, particularly if you use a lot of disks.

I have only two criticisms. It's difficult to find things in the highly detailed manuals as there's no index and the built-in time-of-day clock runs slow, presumably because it's designed for use in the USA with a 60Hz VBI. Frontier Software really should have fixed this before selling the product in the UK.

In summary, if you're a disk user you'll benefit from SpartaDOS. If you're also a 1050 user, you can give your system a tremendous boost by using the combined
SpartaDOS US Doubler package. These products represent unbeatable value and provide you with the ultimate DOS upgrade for your 8-bit machine. Buy them.