[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: minor bug in "du" size calculator in build_all.sh

On 2000-05-27 at 09:54 +0100, Philip Hands wrote:

> Can anyone confirm the rumour about CDs getting steadily more
> unreliable as they approach the 650MB --- I cannot say I've ever seen
> that, and I normally aim to fill the first CD.

I reported this.  It is a matter of compatibility with older readers,
mostly the 2x and 4x proprietary readers which plug into sound cards or
other non-ATAPI drives.  In general, the newer ATAPI drives seem to work
better, but a surprising number of people are using older readers.

The 640 MB point (about 670.000.000 bytes) appears to be where we lose
most of the older readers, and the 650 MB point (about 680.000.000 bytes)  
appears to be where we also lose some of the newer readers.  The very
latest ATAPI drives, 32x or faster, seem to be able to read just about
anything, even some CD-R/W media (which has only about one-third the
amount of reflectivity of CD-R).

> It just occurred to me that because of the 2k rounding thing, the du
> calculation above is going to be inaccurate too.  I'll look at doing a
> du in perl that rounds up to 2k, but won't have time to do it until
> Monday.

You could use the '-k' switch on du and multiply by 1024 using the shell,
which would tend to hit pretty closely.  You could also use the shell '%'
operator with 'expr' and do the calculation exactly, but it is probably
not worth the effort.  I doubt that this is really an issue.

-- Mike

Reply to: