HiassofT's Atari 8bit world

Here is some info about programs I have written and hardware I have developed for Atari XL/XE computers.

AtariSIO for Linux
Atari Tools for Win32 (Windows)
AtariDsk (for MSDOS / Windows)
WriteAtr (for MSDOS / Windows)
MyPicoDos (for Atari 8bit computers)
MyIDE Tool (for Linux/Windows)
Highspeed SIO patch (for Atari 8bit computers)
512k SRAM extension for Atari XL/XE
Turbo Freezer XL/XE 2005 and 2011
SDrive highspeed SIO firmware
Mega Speedy

AtariSIO driver and utilities for Linux

Current version: V0.30-221009

The AtariSIO package contains:

AtariSIO requires a 2.2-6.x series Linux kernel (with enabled module support) and, if you want to use the optimized kernel driver, a serial port with a 16550 or 16C950 compatible chip.

Since version 190111 atariserver and atarixfer also support serial port access via the standard Linux serial API. This means using the kernel driver is no longer mandatory and AtariSIO can also be used with USB SIO2PC interfaces or non-x86 systems like the Raspberry Pi. On x86 systems with a 16550/16C950 serial port it's still recommended to use the atarisio kernel driver as it offers more features and more precise timing.

Since version 180508 the tools adir, dir2atr and ataricom can also be built on non-Linux posix systems (OSX, Cygwin, ...). See INSTALL-tools for details.

You can also download AtariSIO from my GitHub repo

current version:
atarisio-221009.tar.gz 2022-10-09
  • atarisio: fix OxSemi PCIe baud_base issues on recent 5.15-6.0 kernels
  • atariserver, dir2atr: fix image size estimation to ensure we have enough space to add a directory as one of the last entries
  • README.lotharek: document that current SIO2PC/1050-2-PC USB include fixes for +5V and inverted command issues present in first revisions
old versions:
AtariSIO directory   Snapshots are named atarisio-YYMMDD.tar.gz
historical versions:
atarisio-0.10.tar.gz 2003-02-12
  • Initial alpha release
atarisio-0.10a.tar.gz 2003-02-18
  • Fixed gcc-3.x compilation problems
atarisio-0.10b.tar.gz 2003-02-19
  • Updated Makefile and documentation
atarisio-0.11.tar.gz 2003-04-09
  • Added loadable highspeed SIO code to atariserver (thanks to ABBUC!)
  • Added "print directory" function to atariserver
  • Several minor bugfixes and improvements
atarisio-0.20.tar.gz 2003-05-22
  • Added support for DCM/DI/XFD images
  • Added transparent .gz compression/decompression support
  • Added 'all images' option to (un-)protect, uninstall, and write image functions
  • The kernel driver now supports devfs
  • Added support for non-standard SIO2PC cables (command connected to DSR instead of RI)
  • Several minor bugfixes and improvements (see Changelog)
atarisio-0.30-pre1.tar.gz 2004-06-10
  • Completely new curses frontend
  • Added support for linux kernel 2.6.x
  • Preliminary support for the ATP format
  • Lots of fixes and new features (see Changelog for details)
atarisio-0.30-pre2.tar.gz 2004-08-31
  • Fixed kernel 2.6 issues
  • Fixed a bug in atarixfer which prevented writing 180k and 360k disks

Download the atarisio tarball and read the file README for usage and installation instructions.

Here's the Changelog, if you are interested.

Atari Tools for Win32

Current Version: V0.30-221009

This package contains some of the tools from my AtariSIO package, compiled as a Win32 console application:

current version:
V0.30-221009 2022-10-09
  • dir2atr: fix image size estimation to ensure we have enough space to add a directory as one of the last entries
old versions:
V0.30-201020 2020-10-20
  • dir2atr: add support for writing OS/A+ 2.10 and DOS XL 2.30 boot sectors
  • ataricom: add support for exctracting blocks into separate files and specifying multiple ranges
V0.30-190808 2019-08-08
  • dir2atr: add -S/-E/-D/-Q options to create standard SD/ED/DD/QD images
  • dir2atr: fix estimated image size check to properly detect if the image would exceed the 65535 sectors limit
V0.30-190220 2019-02-20
  • dir2atr: add support for MyDOS 4.55 Beta4 and cleanup MyDOS boot sectors
V0.30-190111 2019-01-11
  • dir2atr: Properly set the exit code when adding files failed (eg image full)
V0.30-170924 2017-09-24
  • dir2atr: Add support for MyPicoDos 4.06
  • Various bug fixes and improvements
V0.30-140227 2014-02-27
  • Fixed allowed characters in MyDos mode.
  • Added support for MyPicoDos autorun mode.
  • Support user defined boot sectors, for example to create ATRs with xBIOS boot sectors.
V0.30-101002 2010-10-02
  • Initial release.


Current version: V1.2

Ataridsk is a program for MSDOS-PCs that allows you to access Atari floppy disks in double density (180k). All you need is a PC (XT or 286 should be sufficient) and a 5.25" floppy drive.

Features of this tool:

You can download ataridsk.zip here (22k). Please unzip the file and read ataridsk.doc for installation notes.

The source code to AtariDsk is available here. Please note: You need TopSpeed Modula-2 V1.17 to compile the source.


Current version: V0.92b

With WriteAtr you can write double density ATR-images to Atari floppy disks on your MSDOS-PC. You can also create ATR-images of double density floppy disks! All you need is a PC and a 5.25" and/or a 3.5" floppy drive.

Version 0.92b added experimental support for the enhanced density (1040 sectors/128 bytes per sector) format. Please note: this format doesn't work with a lot of floppy controllers - use it at your own risk!

current version:
V0.92b 2003-07-24
  • Added experimental support for enhanced density format
V0.92b Source 2003-07-24 Note: You need TopSpeed Modula-2 V1.17 to compile the source code
old versions:
V0.9 beta 2002-01-05
  • initial release
V0.91 beta 2002-01-06 Attention - support for XF551 is currently broken!
  • preliminary, untested support for 360k, 720k and 1.44M disks - see writeatr.doc for details
V0.92 2002-03-24 Attention: 720k XF551 mode does not work in this version!
  • support for 180k, 360k, 720k and 1.44M disks in all mappings I currently know of
  • sectors are verified by default when writing a disk
  • enhanced error-reporting and possibility to abort/retry/ignore failed operations
  • plus several smaller bugfixes
V0.92a 2002-12-31
  • Fixed 720k XF551 (3.5") mode
  • Included blank 180k ATRs (to quick-init a disk)
  • Updated the docs

Unzip the file and read writeatr.doc for installation notes.


Current version: V4.06

MyPicoDos is a "gamedos" for the 8-bit Ataris that can read COM, EXE, BIN and BAS files. It's main feature is the ability to cope with the special MyDOS features like subdirectories and large disks (eg 3.5" HD disks). The current version supports all single and double density DOS 2.x and MyDOS formats from 720 up to 65535 sectors and can access D1: to D8:.

Starting with version 3.0 MyPicoDos is GPL'ed and comes with the full source code in Atasm format.

You can also download MyPicoDos source code from my GitHub repo

current version:
mypdos-4.06.zip 2017-09-23
  • Added .CAR file loader for The!Cart and Freezer 2011 versions of MyPicoDos
  • Disable atract mode when using joystick navigation
  • Added directory and drive switching using joystick
  • Bugfix: don't disable highspeed SIO if reading a directory fails
old versions:
mypdos405.zip 2010-11-25
  • Updated highspeed SIO code to V1.30, supporting up to 126 kBit/sec
  • Highspeed SIO can be activated while booting MyPicoDos
  • New PicoBoot boot-sector only COM loader
  • Special SDrive versions with autoswitch to 110 or 126 kBit/sec
mypdos404.zip 2007-08-11
  • Highspeed SIO support for 1050 Turbo, XF551, Happy 810
  • "standalone" .COM versions (loadable from DOS)
  • Stripped-down "barebone" version without highspeed SIO
  • Fixed MyIDE density recognition problems
  • Fixed APE PC-Mirror subdirectory problems
  • Code cleanup to reduce size
  • Changed screen layout (file selection window is now 15 instead of 12 lines)
  • Improved large disk (16-bit MYDOS sector links) detection
mypdos403.zip 2005-03-01
  • Added joystick support
  • Fixed problems with KMK/JZ IDE interface
mypdos402.zip 2004-11-02
  • Fixed corrupted screen in standard SIO version
mypdos401.zip 2004-10-28
  • Support for displaying long filenames
  • Separate highspeed and standard SIO versions
  • Rewrote large parts of the file loader to reduce memory usage
  • Lots of bugfixes and improvements (see README.txt for details)
mypdos30.zip 2003-02-23
  • Added support for SD and DOS 2.x formats
MYPDOS.COM V2.1 1992-03-15
  • Only supports DD disks with more than 1023 sectors!

MyIDE Tool

Current version: V0.30

MyIDE Tool is a program that provides direct access to harddrives in MyIDE format on your Linux/Windows PC. It will work with IDE harddrives, with Compactflash cards attached to either a CF-IDE adapter or to an (USB) cardreader and with images.

You can easily write ATR images and MyIDE movies to your MyIDE drive, list the contents of your drive or back up your data to your PC.

The current version V0.30 also supports Shawn Jefferson's MyIDE Image Manager. You can set the image category when writing (new) images to your disk, or quickly sort the image manager info (a lot faster than on your Atari).
Note: you need to use version 4.1 or higher of the MyIDE Image Manager, older versions are not supported.

current version:
myidetool-0.30.zip 2007-11-11
  • Read/write support for MyIDE partitions and images
  • Support for MyIDE image information (name, density)
  • Support for MyIDE Image Manager (category, sorting, clear and rebuild table)
  • Advanced moviewriter support: write color and grayscale movies (or just other raw data) in IDE (256 bytes per sector) or CompactFlash (512 bytes per sector) mode.

Highspeed SIO patch for XL/XE OS and MyIDE OS

Current version: V1.30

This patch extends the SIO routine of the OS so that the following highspeed SIO modes are supported:

It is the first patch that is 100% compatible with the MyIDE OS (tested with versions 3.x and 4.x). Of course, it also works with the stock Atari XL/XE OS.

The package includes the full source code and a precompiled EXE (patchrom.exe) so that you can create a patched ROM file on your PC (and then, for example, program it into an EPROM).

You can also download the highspeed SIO source code from my GitHub repo

current version:
hipatch-1.30.zip 2010-11-25
  • Optimized highspeed code
  • NMI patch no longer necessary for 126kbit/sec
  • 126kBit work both with new XL/XE OS and old 400/800 OS
  • Code can be compiled as Ultra speed only version
old versions:
hipatch-1.20.zip 2009-05-24
  • Support transfer speeds up to 126kbit/sec
  • SHIFT+RESET does a coldstart
  • Speedup highspeed mode detection
  • Support creation of a patched 400/800 OS on the PC
hipatch-1.12.zip 2008-09-02
  • Added keystrokes to enable/disable/reset the patch and to cold-boot the Atari
  • Fix compatibility with 1050 Happy (fast writes are now enabled by default)
hipatch-1.10.zip 2008-06-24
  • Rewrote large parts of the source
  • Fix compatibility problems with Turbo DOS XL/XE
  • Improve error handling
  • Add fallback to standard SIO speed in case of transmission errors

512k SRAM extension for Atari XL/XE

Current version: V1.3 (released 2010-12-14)

The main goals when designing this SRAM extension was that it should be cheap (less than 10-15 EUR), easy to build (you just need a 512k SRAM, a GAL 22V10 plus a few wires and resistors) and compatible with as many programs as possible.

The extension can be configured to 4 modes (using 2 switches or jumpers):

Optionally you can add battery back-up so that the contents of the RAM extension are preserved when you power off your Atari.

current version:
single ZIP with all files:

separate files:
installation instructions
schematic in PNG format
schematic in Eagle format
GAL source in PALASM format
  • fixed issues with newer BSI SRAMS
old versions:
sram12.zip 2009-09-28
  • initial release

Here are some pictures of an early prototype version installed in my 600XL:

Turbo Freezer XL/XE 2011

The Turbo Freezer XL/XE 2011 is a complete redesign of the previous 2005 model (see below) offering a lot of new exciting features:

The documentation, software (including source), schematics etc. are available at the usual location:

Turbo Freezer XL/XE 2005

The original Turbo Freezer, developed in the end 1980ies by Bernhard Engl, was a very neat hardware device plugging into the PBI that allowed you to halt your computer any time, modify memory and to save or restore a complete snapshot to/from disk, extended RAM or cassette. It was a very valuable device both for developers and for gamers.

The goal of this project was to rebuild the original Turbo Freezer using currently available parts, finally we ended up with a largely enhanced device: The new Turbo Freezer XL/XE 2005 is equipped with 512k flash ROM (64k reserved for the Turbo Freezer software, the rest available to the user) and 128k RAM (16k reserved, rest available to the user, can also be used to store snapshots). The free flash and RAM can be used to emulate cartridges (the hardware supports emulation of standard 8k and 16k carts, 16k OSS-type bankswitching carts and 64k SDX style carts). The built-in software was also significantly enhanced, several new functions like block-move/compare/set, value search, load/save snapshots to Turbo Freezer RAM, swap Atari memory with extended RAM/Turbo Freezer RAM contents, control the cartridge emulation, online-help etc. were added

The documentation, software (including source), schematics etc. are available here:
Please note that there are a few minor errors in the schematics, the 00README.txt in the hardware directory contains an errata.

SDrive Highspeed SIO firmware

This firmware update for the SDrive by Raster / C.P.U. fixes issues with the highest SIO speeds (POKEY divisor 3 and below). See src/ChangeLog.txt for a complete list of changes.

To update the SDrive firmware with avrdude use the following command line (substitute the -c bsd option to match your programming cable):

avrdude -p m8 -c bsd -U lfuse:w:0x3f:m -U hfuse:w:0xdf:m -U flash:w:SDrive.hex:i -U eeprom:w:SDrive.eep:i

current version:
  • Use bit-banged transmission to fix POKEY divisors 3 and below
  • Honor read-only attribute of ATR images
  • Fix issues with QMEG OS 3
  • Fix MyDos formatting issues
  • Fix enhanced density formatting problems
old versions:
sdrive directory Archive of previous development versions


The!Cart is a very versatile flash cart for the Atari 8bit computers. It's main features are:

The!Cart is a co-production between Wolfram "mega-hz" Fischer (original idea, PCB design and manufacturing), Peter "JAC!" Dell (PC software, nice entry selection on Atari) and me (CPLD logic, expert mode cartridge selection menu on Atari, flasher implementation and flash file format design).

The source code and binaries for the CPLD logic, the flasher and expert menu are available here.

The PC based "The!Cart Studio" software (which usually includes my latest Atari software updates) are available on Peter's website

More detailled information and pictures are available on Wolfram's website

Mega Speedy

The Mega Speedy is the ultimate floppy drive upgrade for your 1050.

Out-of-the-box it supports the original 1050, Speedy, Super Speedy, a new Mega Speedy, 1050 Turbo and 1050 Duplicator modes. It can also emulate Happy 1050, US-Doubler, Super Archiver and Supermax modes but you need to provide the ROMs for these upgrades yourself.

Mode selection is very easy, just use the rotary encoder and the display to choose the desired mode on powerup. You can also define up to 4 presets and use 1 or 2 optional switches to quickly select the presets. Or you can switch modes via a bootable menu on your Atari - just boot in Mega Speedy (or flasher) mode with the drive door open.

Drive ROMs are stored in flash memory. For each mode you have 4 slots available so you can switch between different versions / revisions if you like. The flasher software can be booted directly from the Mega Speedy and it also supports uploading drive ROMs to RAM for quick testing or development of new ROMs.

The Mega Speedy project was started by Wolfram Fischer, he did the initial PCB design and built the first prototype that could operate in original and Super Speedy mode. Later he handed over the project to Guus Assmann and me.

I'd like to say a big thank you to Jim Patchell for making the 1050 Duplicator code available to the public and for allowing us to use it and to Steve Carden who did a lot of beta-testing and wrote the installation docs. Thank you!

The source code and binaries for the CPLD logic, the flasher and config drive ROM and the schematics are available here: https://www.horus.com/~hias/megaspeedy/.

General usage instructions and programming information is available in the README.txt inside the megaspeedy-software ZIP.

Also check out Steve Carden's Mega Speedy webpage for installation instructions, pictures and more background information.

current version:
CPLD logic V1.10
software V1.10 (20170923)
  • logic, software: add support for IS Plate mode
  • software: update Speedy ROMs to fix highspeed issues on NTSC systems
  • software: update MyPicoDos to 4.06 final version
old versions:
CPLD logic V1.00a 2015-03-27
  • fix ROM bankswitching in happy mode
software V1.00a (20150304) 2015-03-04
  • update original Speedy ROMs to newer, bug-free version
  • updated Speedy ROMs included in new speedy-roms.atr
CPLD logic V1.00
software V1.00 (20150115)
2015-01-15 Initial release


Current version: V1.30

DiskCart allows you to transfer up to 8 disk images of arbitrary size to flash carts, write images back to disk drives, boot images from the cart or use the integrated MyPicoDos version to start files from the images.

DiskCart runs enntirely on Atari 8-bit computers, only requirements are a minimum of 48k RAM (64k RAM for image boot) and a flash cart.

Currently Atarimax 8MBit, 512k and 4MB Flash MegaCart and Turbo Freezer 2005 and 2011 are supported.

current version:
diskcart-1.30.zip 2020-10-04
  • Add support for Turbo Freezer 2011 with SST 39SF040 flash chips
  • Add 512k Turbo Freezer 2011 mode
  • Update MyPicoDos to 4.06
  • Add atr2cart PC program to create ROM images
old versions:
diskcart-1.21.zip 2013-04-22
  • Add support for 4MB Flash Megacart, Atarimax/MegaMax 8MBit, TurboFreezer 2005 and 2011
diskcart-1.0.zip 2010-08-16
  • Initial version for 512k Flash MegaCart


If you have suggestions for future versions or problems with these programs, please send me an email.