[SLE] DMA disk access - have I missed something?
In the Vmware newsletter which has just been sent around I saw this: "If you're a Linux-host user, don't forget to also turn on DMA on your host operating system. If you have IDE disks, use the command "/sbin/hdparm -d 1 /dev/hda" to enable DMA. The result: VMware, and all your other applications, will run faster." It never occured to me that my disks might not be using DMA transfers. I checked my system here at work (SuSE-6.2, 2 IDE disks), and both disks are using DMA transfers. My Dell laptop (SuSE-6.4) has DMA switched off. I'll check my machines at home tonight. What decides, in a SuSE distro, whether DMA is being used? The hdparm man pages suggests (under the -X section) that the drive switches to it's fastest mode at power on, which, if true, would make the above tip irrelevant. Can someone fill me in? -- To unsubscribe send e-mail to suse-linux-e-unsubscribe@suse.com For additional commands send e-mail to suse-linux-e-help@suse.com Also check the FAQ at http://www.suse.com/Support/Doku/FAQ/
Hi All & Derek, who wrote, <snip>
In the Vmware newsletter which has just been sent around I saw this:
"If you're a Linux-host user, don't forget to also turn on DMA on your host operating system. If you have IDE disks, use the command "/sbin/hdparm -d 1 /dev/hda" to enable DMA. The result: VMware, and all your other applications, will run faster."
It never occured to me that my disks might not be using DMA transfers. I checked my system here at work (SuSE-6.2, 2 IDE disks), and both disks are using DMA transfers. My Dell laptop (SuSE-6.4) has DMA switched off. I'll check my machines at home tonight.
What decides, in a SuSE distro, whether DMA is being used? The hdparm man pages suggests (under the -X section) that the drive switches to it's fastest mode at power on, which, if true, would make the above tip irrelevant. Can someone fill me in?
<snip> Some machines will not go, with DMA turned on. This is what kept me off Linux for a couple of months, unknowingly. I think that is why it is turned off by default. But, my new hardware is a different story :-) Information re DMA, can be got via this command line man hdparm or check out /usr/doc/howto/en/mini/Ultra-DMA.gz "hdparm" is the application that enables DMA transfers. To see if you have it going, type this @ the command line hdparm /dev/hda where /dev/hda is your first HDD.... To figure out how fast your transfer rate is issue hdparm -Tt /dev/hda I get hdparm going by adding this command in my /sbin/init.d/boot.local hdparm -d1c3X34S 60 /dev/hda hdparm -d1c3X34S 60 /dev/hdc Hope this helps & *BFN* Greek Geek :-) Linux.....The Ultimate NT service pack. -- To unsubscribe send e-mail to suse-linux-e-unsubscribe@suse.com For additional commands send e-mail to suse-linux-e-help@suse.com Also check the FAQ at http://www.suse.com/Support/Doku/FAQ/
participants (2)
-
bobbyg@ihug.co.nz
-
fountai@hursley.ibm.com