Why does there need to be a limit at all? Isn't there a way to dynamically allocate that sort of thing?

The limit isn't on the size of playlist you can play, it's on the size of playlist you can remember and restore over a power-off. The player uses a special disk partition for this kind of data: one without a filesystem on, one which is read and written directly at the sector level.

Because there is no filesystem on this "dynamic data" partition, the allocations to various uses (bookmarks, playcount etc. live on there too) are fixed. And the allocation for remembered playlists is simply too small.

The reason there's no filesystem, is to avoid the chance of the whole lot getting hosed in the case of power failure: the dynamic data partition, unlike the music or root partitions, is rewritten at arbitrary times in-car, and so we must cope with power fails at any moment.

Peter