I'll try this again.

For those who want the technical details:

The "TD64" commands were an unofficial set allocated some years ago to support 64-bit addressing in disk drivers. They used the command values:
TD_READ64=24
TD_WRITE64=25
TD_SEEK64=26
TD_FORMAT64=27
- which were at that time the next unallocated command values. These commands were not supported by AmigaOS, but by add-on hacks.

The NSD (New Style Devices) commands for device drivers in 3.? allocated new commands that had identical form and function, but different command values:
NSCMD_TD_READ64 = 0xC000
NSCMD_TD_WRITE64 = 0xC001
NSCMD_TD_SEEK64 = 0xC002
NSCMD_TD_FORMAT64= 0xC003
These commands are supported by all OS4 device drivers.

This release provides a "wedge" or hack that simply replaces "TD64" commands by the corresponding "NSD" command. It does not check whether the device actually supports the TD64 or the NSD commands, so could pose problems in some conditions.

Using this hack, you can then run old software that expects to find the TD64 commands supported.

It would be simple to add the TD64 commands to existing OS4 drivers, although it would require a lot of testing to ensure that there are no side effects.
Also, it is always possible that in future releases of AmigaOS, the command values used by TD64 will be assigned for other purposes (not likely, but possible).

@tonyw

The version 0.2 I have just uploaded to OS4Depot does some more tests to see if the device is suitable for patching (checks whether it is a trackdisk-type device, whether it supports NSD64/TD64, etc.).

The version 0.1 was supposed to be a quick release to see if this would actually work and only meant for people who know what they're doing, i.e. doesn't try to patch audio.device or anything equally silly.

See Ralph Babel's Amiga Archive for TD64 and NSD.

Thanks for the link itix but it doesn't change the fact NSD is the Amiga OS standard which is the main problem. What we need is for TD64 to be merged into NSD before they become totally incompatible. Perhaps that will be done in the future. In the mean time, this patch will have to do.

this will be very usefull indeed :)