I do wonder where this thread is going
I assume many here (if not most) are familiar with TopfHDRW? It exists because Topfield developed a non-standard file system for pvr use. That non-standard file system is FAT based and uses large cluster sizes which mitigate the effects of file fragmentation.
If Topfield felt the need to develop their own file system why do some people have such a hard time accepting that other manufacturers might have felt a similar need but arrived at a different solution?
There has been considerable effort put into file system development over the past 15 years by different groups.
The Linux ext2 files system has morphed into ext3 and then ext4. These address many of the issues a pvr manufacturer would have faced in the mid 1990's.
Silcon Graphics developed XFS in the 1990's. As you can see from this link
"XFS is particularly proficient at handling large files and at offering smooth data transfers."
It was released under GPL in 2000 and is now used in a number of pvrs.
As a result of the efforts of many people over many years you can today get an "off-the-shelf" file system suitable for use in a pvr. This doesn't mean however that Topfield and TiVo were idiots for developing their own file systems. At the time they had to. Nor does it mean there is a right way or a wrong way, both came up solutions that worked for them.
I do hope we can move on from this idea there is only one way to build a pvr.