1. General Information

1.1 What is this Atari ST thing?

The Atari ST is a 16/32 bit Motorola 68000 based personal computer range launched in the mid 80's which has evolved over the years from the ST to the STF, STFM, Mega ST, STE, Mega STE, and into more modern computers like the TT030 or Falcon030.

There are even some extremely powerful Atari-compatible clones around like the swiss 68060 based Hades or the german Milan, and clone projects like the french Phenix or the american Wizztronics machine.

These computers run various flavours of an operating system called TOS (The Operating System), which includes GEM, a graphical user interface from Digital Research.

More details on various machine specifications can be found here:

If you are interested in the fate of Atari, and the company's history, you might want to visit the following places: Modern Atari clones can be found here:

1.2 What kind of monitor can I use ?

STFMs and later models were equipped with an RF Modulator allowing them to be connected to a TV's antenna connector. You then need to tune into the correct channel on the TV to get the ST picture.

In some countries, Atari shipped machines with a SCART/Peritel cable that plugs into the monitor port instead of the RF Modulator. In this case you need the adequate cable and a SCART/Peritel equipped TV set. No tuning is required, and the RGB picture is better quality than RF. These cables might still be available from some Atari dealers, but it is also quite easy to home-build one, provided you know the pinouts (see section 3.7).

A TV will act exactly like an Atari Colour Monitor, and therefore will only display low or medium resolution modes.

First of all, the Atari ST has 3 screen resolutions: 1 monochrome (Hi-res), and 2 in colour (Mid-res and Low-res)

Monochrome (640x400) requires special Atari high resolution 72Hz monitors (SM models). These monitors have a very stable, although small, paper white display. SM monitors can only display monochrome mode. TTs and Falcons can do without the SM monitor and display ST high-res on a VGA monitor.

ST Medium (640x200/4 colours) and ST Low (320x200/16 colours) need a colour monitor (SC series) or a TV.

Note that a monochrome display can only show Hi-res, and a colour monitor (or TV) can only display Mid-res and Low-res. Most games require colour, and most application programs require Hi-res, so the choice of your monitor is important.

If you want to display all ST screen resolutions with an ST/STF/STFM/STE you need both types of monitors or you can use a multisync monitor with a special adapter. A temporary solution for running monochrome programs on a colour monitor, can be to use a software Hi-res emulator such as Sebra (see section 2.2.3).

These monitors cannot be connected to a TT, as this machine requires a VGA monitor.

First of all, you need a monitor that supports RGB signals, and the following refresh rates : Note that a modern day standard VGA monitor can only handle the ST's monochrome frequencies. In this case, you need to connect the ST's mono out to the red, green and blue inputs of the monitor. Connect the H-sync and V-sync signals, and the ST's mono-detect pin to ground.

For a multisync or any other RGB display that can handle the above display rates (including a SCART equipped TV set), you will need to build a simple adaptor that connects the red, green and blue outs, the H and V sync signals, and ground from the ST monitor output to the display unit's connector. Leave the mono-detect pin disconnected.

Connector pinouts can be found in Section 3.7 of this FAQ. The proprietary connector used on the Atari can sometimes be difficult to find. A source in the UK is Maplin's. In Europe (at least Germany and France), you can try Conrad Electronics. In the USA, the best source for such parts is probably Best Electronics.

Instructions on building a multisync adaptor for the ST can be found here:

The Falcon is equally happy with a VGA/SVGA/etc. monitor or an old ST/STE type monitor (though resolution will be limited to 640x400 interlaced on these).

Whatever the display you choose, the Falcon requires an external video adapter, either for ST type monitors or for VGA screens. There are also third party adapters that can switch between the two displays.

A text file about Multisync/VGA/ST-res adaptors for Falcon is here:

1.3 How do I get it to boot up ?

First of all, most Atari computers have TOS in ROM and therefore don't need a boot disk. If you do not have a correctly formatted double density disk to boot from, just wait a few minutes for the GEM desktop to come up on it's own, then format a blank double density disk using the menu option. Having a formatted disk in the drive dramatically shortens the bootup time.

If the desktop screen doesn't come up after more than 5 minutes, either your ST is broken or you have an ST without TOS in ROM. Only some of the first pre-STF machines (the ones with no floppy drive) needed a special TOS boot disk without which they are more or less useless. If you happen to have one of these machines, you should seriously consider a TOS upgrade (see section 2.4).

If you have never used an ST and don't have a manual on hand, there is little you need to know to use the desktop. The GEM desktop is the where you will do all file operations and launch programs, here are the basics: Once you have got the hang of this, the rest is pretty straight forward. This is for all TOS versions. Newer versions of TOS have additional features.

An explanation of the contents of the DESKTOP.INF and NEWDESK.INF files can be found here:

1.3.3 Atari language disks

Depending on the ST version you have, a language disk was supplied with some basic software, mainly: Very few of the programs supplied on these disks were of much use. If your system disks have been lost, it is no big deal. Better public domain or shareware equivalents can be found on most FTP servers (see section 2.2.3). Software supplied with the Falcon included several commercial programs such as MultiTOS, Atari Works or SpeedoGDOS. These are not freely available.

1.3.4 How do I know what TOS version I have

One way to find out which version of TOS you are running is to check out the latest copyright date in the Desk, Information box.
1985: TOS 1.00 (ST/STF) - original ROM version
1986: TOS 1.02 (Mega ST) - blitter support
1989: TOS 1.04 (STF/Mega ST) - coloured atari logo, better disk I/O, many bugfixes, faster.
1990: TOS 1.06 (STE) - STE hardware support
1991: TOS 1.62 (STE) - bugfixed version of above
1990: TOS 2.05 (Mega STE) - new desktop, customizable icons, HD disk support
1991: TOS 2.06 (Mega STE) - bugfixed version of above, support for future hardware.
In addition to these, a Falcon will be running TOS 4.02 or 4.04 and a TT030 will have TOS 3.01, 3.05 or 3.06. The new Milan computer runs a licensed TOS 5.0.

For any serious use, versions of TOS below 1.04 should be upgraded. See section 2.4.

To obtain a full report on your hardware (RAM, TOS, disks, etc...), you should run a program such as Sysinfo.


1.4 Emulators

You need a program that will fool your computer into running Atari ST programs. This is called an emulator. There are plenty of them available on the Internet.

Here are some good net resources for Atari emulator software:

TOS is the ST's operating system. It was supplied on ROM chips with most Atari machines. Some emulators need an image of these ROMs in order to run.

However, TOS is still copyrighted software and the distribution rights belong to Atari. Neither Atari nor JTS (the company who now owns Atari) has stated that any version of TOS can be freely distributed and used. Distributing it without a licence is therefore software piracy, which is illegal and enforced everywhere in the world.

Solliciting pirated software is also illegal.

Owners of a real ST can use a program called TOSDUMP.PRG to make a TOS image for their own use. This is considered legal as long as the image is not distributed and you own a legal copy of the program (ie: the ROMs).

Illegal copies of TOS images can be found at the following location. Remember that using them is software piracy. See section 2.1.

The Little Green Desktop

1.4.3 What are .ST files and what can I do with them ?

Emulators often have problems reading original ST floppy disks, mainly because of hardware issues on the emulating machine. A common workaround is to convert all the data contained on a disk (including special formatting, boot sectors, hidden tracks, etc...) into a disk image file. The most common format for this is the .ST file format from PaCifiST. The emulator then mounts the files as if they were real disks.

Here are various utilities for converting disk image files into disks, and vice versa.

ST2DISK (Atari)

Makedisk (DOS)

Dust (Mac)

Many .ST files that are on the net are actually pirate copies of games. Even if these games are no longer produced or sold as new, unauthorized distribution and use of copyrighted software is still illegal. See section 2.1.

1.5 Will the Y2K bug affect my Atari ?

There is a lot of hype around the Year 2000 bug, much of which actually comes from people who are making profit out of PC users' ignorance. The problem mainly affects old mainframe-type programs where the programmers coded years in 2 digits (00-99) instead of using the correct 4 digit form (0000-9999).

First of all, Atari ST, STF and STE computers do not have a real time clock (RTC) to begin with, so unless you set the time/date on every boot, they still figure they are somewhere in september 1986. On the other hand, other Atari computers with a built-in RTC were all designed to go way over 2000. Although the limit is not clearly defined, it appears to be somewhere after 2028. TOS also is also capable of tracking time at least up to this date.

Basically, the hardware and system software DO NOT suffer from any millenium bug.

As far as software goes, most programs do not even use any RTC or date functions. This will be true for games and 90 percent of your other software. What might suffer is any database program with some built in date tracking that does not comply with the system standard.

Another identified problem is for aftermarket RTCs, like the Forget-me-clock, which will happily tick on to the next millenium, but for which the setting software will not work anymore.

There is a web site specially dedicated to Atari and the Y2K issue.

Atari ST Quick FAQ - v2.9a - bales@online.fr