Re: dvd+rw-tools update [6.0, DVD-R DL]
scdbackup@gmx.net writes:
> > > How come that the time granularity of the backup processing chain
> > > does not get finer as the systems get faster ?
> >
> > What do you understand by time granularity?
>
> I see a fifo as a method to smoothen out peaks and gaps in a
> input function and to bring the output nearer to the input
> average.
> The intensity of peaks and gaps resp. the deviation from the
> average can be characterized by the time span in which one
> may expect that those irregularities compensate each other.
> The product of this time span and the average speed determines
> the size which is needed for an effective buffer.
> This time span is what i mean with "time granularity".
>
> If the overall system gets faster, i would expect this
> characteristic timespan to get shorter. But it seems to
> stay within the range of several seconds.
> Since the average speed grew and the time staid more or
> less the same, the fifo size had to grow.
>
> The only logical explanation is that the characteristics
> of the input function have changed while the system
> became faster.
...
> I'm still riddling.
> What effect did change the shape of our input functions ?
I think the main problem is that hard disk seek times have not
improved anywhere nearly as fast as the CD/DVD writing speed. The
difference between 1X CD speed and 16X DVD speed is approximately a
factor of 150. Compare this to hard disk seek times which improved
probably less than a factor of 2 during the last ten years.
This means that, relatively speaking, you will suffer much more today
than in the past, if you are not reading sequentially from the hard
disk, ie if you are accessing many small files that are spread out all
over the disk.
--
Peter Osterlund - petero2@telia.com
http://web.telia.com/~u89404340
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