Re: filmscanners: USB and data transfer as a constraint on time

[Arthur Entlich <artistic@ampsc.com>]

patton paul wrote:

> The new Nikon and Minolta scanners use USB rather than SCSI to communicate
> with the computer.  Since USB has a lower data transfer rate than SCSI, I
> was wondering wether this makes any difference for the overall amount of
> time needed to complete a scan.  Is data transfer speed the limiting
> constraint on the amount of time needed to complete a scan, or is there
> some other aspect of the scanning process that constrains speed?
> 
>

Paul,

This is a difficult question to answer.  Because theory seems to differ 
from real world experience.  Theory say it shouldn't matter because even 
USB is fast enough for the speed the scanner can provide the data.

In practice, it is difficult to prove because each scanner uses 
different software buffering techniques, and often different quality 
controllers.

The only factual info I can provide is that HP originally made a SCSI 
version of their film scanner.  The second model was of the same 
resolution but captured at a higher bit depth (more data), but was USB.

The USB version was about 1/3rd slower than the SCSI model, but it also 
provided nearly 1/3rd more data due to the difference in bit depth 
captured.  This would support the idea that USB is "fast enough".

Art