24 Apr
2018
24 Apr
'18
10:32 a.m.
On 04/23/2018 05:44 PM, Johnny Billquist wrote:
But this whole optimization for swap based on transfer
speeds makes no
sense to me. The dominating factor in spinning rust is seek times, and
not transfer speed. If you place the swap at one end of the disk, it
won't matter much that transfers will be faster, as seek times will on
average be much longer, and that will eat up any transfer gain ten times
over before even thinking. (Unless all your disk ever does is swapping,
at which time the heads can stay around the swapping area all the time.)
I wonder if part of the (perceived?) performance gain was from the
likelihood that swap at one end of the drive meant that things could be
contiguous. Seek, lay down / pick up a large (or at least not small)
number of sectors, and seek back.
I had always assumed that the outer edge (what I thought was the end of
the disk) was faster than the inner edge (what I thought was the
beginning of the disk) because of geometry. However, as Ronald stated,
hard drives were constant angular density. Thus negating what I
originally thought about speed.
--
Grant. . . .
unix || die