On Thu, Aug 15, 2013 at 1:45 PM, Carlos E. R. <robin.listas@telefonica.net> wrote:
Fyi: per Linus, disk cache is internally organized in track size chunks. A typical track can hold 1mb, so a 8mb cache on the drive controller can
1 MB per track? Then a 1 TB disk would have a million tracks? Surely a track is bigger.
Yes and no. If a 1 TB drive has 4 heads, then it 250,000 cylinders. But a cylinder would have 4 tracks, so yes it is 1 million tracks total, but only 250,000 per platter surface. I'll let you do the math, but this is how I do it: A 7200 RPM disk does 120 revolutions per second. At its fastest speed it is reading (or writing) data continuously, so that is 120 tracks per second continuous at its fastest A fast SATA drive transfers about 120 MB/second. Thus 1 track = 1MB. If the bottleneck is something other than how fast the media moves underneath the disk head, then my analysis is wrong, but I really do think that the limiting factor is how fast the drive is spinning. Greg -- Greg Freemyer -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org