Re: Strage buffer behaviour

2007-11-14 Thread Tomasz Chmielewski
Denys Vlasenko wrote: On Sunday 11 November 2007 11:33, Tino Keitel wrote: The dd command reads 100 MB from each partition two times in a row. It looks like sda1 and sda2 are not bufferd (the first 4 dd runs), but sda3 and sda4 are (the last 4 dd runs). The computer is a Mac mini with a 2,5" S

Re: Strage buffer behaviour

2007-11-12 Thread Heikki Orsila
On Mon, Nov 12, 2007 at 12:44:53PM -0700, Denys Vlasenko wrote: > IIRC only mounted partitions' reads are cached. That seems to be the case. Thanks. -- Heikki Orsila Barbie's law: [EMAIL PROTECTED] "Math is hard, let's go shopping!" http://www.iki.fi/shd - To unsu

Re: Strage buffer behaviour

2007-11-12 Thread Denys Vlasenko
On Sunday 11 November 2007 11:33, Tino Keitel wrote: > The dd command reads 100 MB from each partition two times in a row. It > looks like sda1 and sda2 are not bufferd (the first 4 dd runs), but > sda3 and sda4 are (the last 4 dd runs). > > The computer is a Mac mini with a 2,5" SATA hard disk. Th

Re: Strage buffer behaviour

2007-11-11 Thread Heikki Orsila
On Sun, Nov 11, 2007 at 07:33:35PM +0100, Tino Keitel wrote: > I noticed that the kernel (2.6.23.1) seems to buffer only certain > partitions on my system: > > $ for i in 1 2 3 4 ; do for j in 1 2 ; do dd if=/dev/sda$i of=/dev/null > bs=1024k count=100 ; done ; done > 100+0 records in > 100+0 reco

Strage buffer behaviour

2007-11-11 Thread Tino Keitel
Hi folks, I noticed that the kernel (2.6.23.1) seems to buffer only certain partitions on my system: $ for i in 1 2 3 4 ; do for j in 1 2 ; do dd if=/dev/sda$i of=/dev/null bs=1024k count=100 ; done ; done 100+0 records in 100+0 records out 104857600 bytes (105 MB) copied, 3.01471 seconds, 34.8 M