> thanks. > do I really need to update my current CHD files ? I'm asking because I just tried > vaportrx without updating the CHD file and it still works. > > also, I used chdman to update the file and it got bigger... I thought this new header > version would make CHD files smaller.
no. updating chds to v5 will only save some space (how much depends on the CHD, and Laserdisk will save less than others), but v4 CHDs will remain fully compatible for long time
the only exception is for MESS CHD containing hard disk images for PC or Mac drivers: those CHDs needs to be writeable for the emulated OS to write on them, and therefore they need to be updated because v4 compatibility is read only.
summarizing: read-only CHDs (*all* MAME ones and the MESS ones containing CD dumps) do not need to be updated unless you want to see how much space you can save; writeable CHDs (MESS one for emulated HDs) need to be updated to keep working