Topic: Should 32 Bit Disk Access be enabled?

[paulmancan2]

I was fooling around with hdparm and noticed that my drives are set to 16bit.... I'm not sure about linux but shouldn't these be set to 32bit if the hardware supports this?

Thanks!

[mbachmann]

Some mainboards had it to be first enabled in the bios ("32 bit access mode" or similar). Then try hdaprm.

[paulmancan2]

Thanks.... it is enabled in the BIOS..... Is 16 bit the default for this distro/linux in general and if so, do ppl generally leave it this way?

I set it to 32 with hdparm and try using -k to keep these changes but they disappear anyway after reboot!

Thanks!

[Brave Dave]

I note you also post about the timeout issue, so maybe 32 bit is not for you, but 32 bit is much faster, so if you can you enable it you would enjoy the speed benefit

but i'm sure it's enabled in the newer sme, 5.5, I think, had the hdparm package which enabled it separately, but I think that was a change from 5.5 - 5.6

[hardijs]

I do usually enable it - provided the motherboard + HD are new enough + there is more than enough RAM - 256+.

try hdparm -i [yourdrivedev]

if the drive lists as udma 3 and above it's worth trying.

depending on what drive / moBo you have there may be different results

here's an example
hdparm -i /dev/hda

/dev/hda:

 Model=WDC WD400JB-00ENA0, FwRev=05.03E05, SerialNo=WD-WCAD1A235289
 Config={ HardSect NotMFM HdSw>15uSec SpinMotCtl Fixed DTR>5Mbs FmtGapReq }
 RawCHS=16383/16/63, TrkSize=57600, SectSize=600, ECCbytes=40
 BuffType=DualPortCache, BuffSize=8192kB, MaxMultSect=16, MultSect=16
 CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=78165360
 IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
 PIO modes: pio0 pio1 pio2 pio3 pio4
 DMA modes: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 *udma5
 AdvancedPM=no WriteCache=enabled
 Drive Supports : Reserved : ATA-1 ATA-2 ATA-3 ATA-4 ATA-5

[root@sargs root]# hdparm -tT  /dev/hda

/dev/hda:
 Timing buffer-cache reads:   128 MB in  0.80 seconds =160.00 MB/sec
 Timing buffered disk reads:  64 MB in  1.38 seconds = 46.38 MB/sec



I doubt that much more from this drive can be obtained.....

[KelvinLee]

Hi Paul,

You have not mentioned what chipset your Controller (motherboard) is using. Chances are SME (or rather the base linux kernel) does not have native support for that chipset. This is a problem I've been struggling with for all the current motherboards I'm using (ie. no native support for the new VIA chipsets) so I can't get high speed DMA access to the drives and so far, I have not come across anyone who has posted a patch to enable this yet for SME. I have not had any success in the past trying to patch it myself (lack of knowledge).

Kelvin