FYI: {CD,DVD}-ROM ATA mode, 5.1R

[toposoph-space at yahoo.com]

Hi,

Just for information, may be it is already well known:
I found that by default all ATA CD- and DVD-ROMS have PIO4 mode (at
least on my machines, 5.1R). Changing mode to at least UDMA33
(atacontrol) improves performance dramatically - not just transfer
speed increased, but (and this is more important) interrupt time
reduced (according to systat -vmstat: from 40% to 0.8%).

Regards,
Sergey.