lkml.org 
[lkml]   [2001]   [Mar]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: UDMA 100 / PIIX4 question
    > > > I have an IBM DTLA 307030 (ATA 100 / UDMA 5) on an 815e board (Asus CUSL2), which has a PIIX4 controller.
    > > > ...
    > > > My problem is that (according to hdparm -t), I never get a better transfer rate than approximately 15.8 Mb/sec....
    > >
    > > 15MB/s for hdparm is about right.

    it's definitely not right: this disk sustains around 35 MB/s.

    > Yes, since hdparm -t measures *SUSTAINED* transfers... the actual "head rate" of data reads from
    > disk surface. Only if you read *only* data that is alread in harddrive's cache will you get a speed
    > close to the UDMA mode of the drive/controller. The cache is around 1Mbyte, so for a split-second
    > re-read of some data....

    nonsequitur: the controller and disk are both quite capable of
    sustaining 20-35 MB/s (depending on zone.) here's hdparm output
    for a disk of the same rpm and density as the DTLA's:

    Timing buffer-cache reads: 128 MB in 1.07 seconds =119.63 MB/sec
    Timing buffered disk reads: 64 MB in 2.02 seconds = 31.68 MB/sec

    (maxtor dm+45, hpt366 controller)
    regards, mark hahn.

    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-03-22 13:29    [W:0.021 / U:1.440 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site