2004.10.01 07:22 "[Tiff] BigTIFF extension issue", by Joris Van Damme

2004.10.03 15:59 "Re: [Tiff] Re: BigTIFF extension issue", by Bob Friesenhahn

I don't think you can use the argument that no existing standard TIFF reader can read BigTIFF. The case of tiled tiff vs previous tiff is one example, but perhaps not a good one. So, take PostScript or PDF as perhaps a better example. We had PS Level 1, then Level 2 then Level 3. We had PDF 1.0, then 1.2, then 1.3, then 1.4. I think everyone would agree that there was no new file format. But no laserprinter that was Level 1 could print a Level 2 file. In this case one would argue that the file format was the same, but the commands/operators were different.

The file formats were clearly different. The base format provided a means to identify the format "version" or "level". A laser printer which was Level 1 can print a "Level 2" file as long as the "Level 2" file is constrained to using Level 1 features.

Do not confuse file structure with format. Format is a very precise thing. Structure implies a way of doing things which may be similar across multiple formats.

If there is a tag in there indicating it's big tiff, apps can very soon rev to support this and give a warning. People have to upgrade their apps periodically, as older apps don't even run on later OSs. So within a few years all (most) the apps people use will deal with big tiff .tif[i] file correctly. And big tiff files will only be common in general open use (as opposed to closed loop systems) in a while anyway.

I am quite happy with using the `xv' program (include includes a copy of libtiff). This program stopped being developed in 1993 yet it continues to work just fine. The failure for applications to continue working is an artifact of certain operating systems which were either poorly designed in the first place, or for which forcing continued application upgrades and chaos leads to more wealth for the OS vendor.


Bob Friesenhahn