On Sun, Aug 29, 1999 at 01:07:19AM -0700, Tom Livingston wrote:
> Also, Jan mentioned test speeds from both inner cylinders and outer
> cylinders. 18MB was the number for inner cylinders, which is very close to
> your own number. Does hdparm -tT /dev/hdc test from the inner or outer
> cylinders? If it starts from block 0, it will be reading from the inner
> ones, no? As drives spin at a constant speed, but there is more surface
> area on the outside of the platter, more data is read (faster MB/sec) per
> one rotation.
Based on measurements of drives over the years, I believe block 0 is
always on the outer cylinder. Lower numbered blocks are always faster
than higher numbered blocks, in my experience. Of course, there's no
physical reason why it should be so; manufacturers could just as easily
do it the other way. But I appreciate that there appears to be
a convention.
Jan Edler
NEC Research Institute
