Subject: Re: ATAPI UltraDMA questions...
To: Wolfgang Rupprecht <>
From: None <>
List: netbsd-users
Date: 02/28/2001 20:47:19
> I think the raw performance of IDE is quite good (especially if you
> only put one disk on a cable). The IBM DTLA-307075 (an IDE drive)
> reads at 36.4 MBytes/sec.
>     # dd if=/dev/rwd1d of=/dev/null bs=64k count=40000
>     40000+0 records in
>     40000+0 records out
>     2621440000 bytes transferred in 72 secs (36408888 bytes/sec)
> Thats not that shabby...  
> The one caveat is that all current drives are zoned, meaning that they
> are faster on the outer (low-numbered) tracks than the inner ones.
> The above IBM slows down by a factor of ~2 on the inner tracks.

yes... and an average transfer is something like 80% of maximum (there's
more data on outer/faster tracks than on closer/slower tracks)

the same is for SCSI drives..