Colin wrote: > Maybe you can answer this question. I have an ATA/66 hard drive (66 > MBps) on an ATA/133 bus. If the bus is limited to 133 MBps and the > drive cannot transfer data at more than 66 MBps, how come burst > transfers (as reported by hdparm -tT /dev/hdg) are at about 1.6 GBps? > > Not that I'm complaining, of course, it just seems illogical :-) >
Is it try-to-stump-Richard-day again already??? ;-> It is because of the way the -T test is implemented, which is to just read the first block of data over and over again. Because hdparm doesn't specify the O_DIRECT flag on open, the kernel will buffer the data in system memory for the first read, and return the same for all subsequent reads. So the number returned equals 1/2 of your system memory bandwidth, since copying the buffer from one memory location to another involves both reading and writing. -Richard -- gentoo-user@gentoo.org mailing list
