How is TD64 implemented?

[olsen]

Thanks Thomas. I wasn't thinking of patching driver or filesystem with setpatch, just wondering how the other components were updated to use big partitions.

Like I said, there are some mentions of such components "in Workbench" but no data about which components or which WB.did not need patching and would work with a correct x.driver and filesystem that used TD64.

I updated workbench.library and a handful of other components (the "Info" command, for example) for Workbench 3.5 so that they would know how to handle quantities larger than 4 GiBytes. These were no fundamental changes, such as would be needed for the "DiskCopy" command, for example. Workbench 3.5 also replaced the "HDToolbox" utility with a different program which could cope much better with large storage media. The changes in the scsi.device (IDE and SCSI flavours) as well as the FastFileSystem complemented these. Still, plenty of software which shipped back then did not get updated to handle large storage media, or large numbers (in excess of 4 GiBytes).

The point being at which point a floppy only user could use a PCMCIA adapter with larger than 4GB partitions on it with legacy Commodore disks.

The "card.resource" and "carddisk.device" were not updated, and if I remember correctly, this is not a limitation as such. "card.resource" provides a interface to access the PCMCIA hardware, such as its chip registers. If a disk driver uses "card.resource" to access a storage device, it's the job of that disk driver to provide for large storage device command support, not "card.resource". The "carddisk.device" is a slightly different matter, as it makes the volatile/non-volatile storage on a PCMCIA card available as a local storage device. The space allotted for such cards in the larger Amiga memory space limits the size of PCMCIA card's volatile/non-volatile RAM that can be used. You won't even reach 2 GiBytes of RAM

[olsen]

carddisk.device is not able to handle CF cards.

Could be because of its age (a bit too early for CF cards, which seem to have first hit the market around 1994) and the PCMCIA standard as implemented (1991/1992) and then frozen in time

If I remember correctly, the kind of volatile memory Commodore's implementation was designed for was either DRAM to extend the capacity of Amiga main memory, or alternatively as a RAM disk drive (RAD: implemented entirely in hardware, if you will). There was also the option to have the Amiga boot off a PCMCIA card specially prepared for the Amiga to make use of it, e.g. a game cartridge (as a more than slightly upmarket alternative to a CD-ROM disc).