size discrepancy

[Andre Robatino]

Tim <ignored_mailbox <at> yahoo.com.au> writes:

> 
> On Sat, 2010-10-02 at 10:52 -0700, JD wrote:
> > The actual physical size on the DVD seems to have been padded by 10240
> > bytes (not sure if that is done during dvd burn, or during dvd read),
> 
> When one uses features like "burnproof" so that the burning process can
> pad out buffer underruns, and keep on burning until more data comes
> through, instead of halting, is that transparent to the (later) reading
> of the disc, or a likely cause of this sort of problem?

Due to the linux readahead bug, which has never been fixed, padding is a Good
Thing (as long as there's a little extra space on the disc to allow it). I
always use the isopad script at

http://ftp.cs.utoronto.ca/pub/hugh/isopad

before using growisofs to burn discs. When using wodim, its -pad option can be
used. (The -pad option for growisofs is not the same and in fact can't be used
when burning an existing ISO file.) The proper way to avoid problems with read
size is to always specify the correct size in the dd command - which the rawhide
script does, assuming the ISO header information is correct, otherwise it has to
be done manually. If the size isn't specified, whether it works is
hardware-dependent.