[TUHS] /dev/drum

[Grant Taylor]

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

-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 3982 bytes
Desc: S/MIME Cryptographic Signature
URL: <http://minnie.tuhs.org/pipermail/tuhs/attachments/20180423/da65f2ca/attachment.bin>