|
PureBytes Links
Trading Reference Links
|
I did further tests using Win98 and an old UDMA 33 drive
Using the 10MB 65536 block test I found the following
No DMA reads 5225
DMA enabled 13037
It also appears that the CPU utilization has dropped to about half (it
depends on the tasks run)
I hpe this helps with older machines
http://www.a1-electronics.co.uk/GeneralTips/GenTips_pg5.html
Get DMA working.
You really need to get your system setup for DMA. This really does give
performance improvements from 15% in drive performance and will reduce the
load on your CPU by up to 40%. DMA is a way a part of your computer system
bypasses the CPU and takes a short cut through your system, making it
quicker to transfer data.
Checking your DMA settings.
Came across this. When you enable DMA by using the Device Manager and
ticking the DMA box it might not always be enabled. One way to check is to
open a Windows file, "Mshdc.inf" found in Program Files/Windows/INF and look
down that file for a header called "ESDI_AddReg". It should look apparently
like:
ESDI_AddReg
HKR,,DriverDesc,,"ESDI Port Driver"
HKR,,DevLoader,,*IOS
HKR,,PortDriver,,ESDI_506.pdr
HKR,,IDEDMADrive0,3,01
HKR,,IDEDMADrive1,3,01
Apparently if the last two lines are shown (with the other 3) you are set.
If not, add the last two lines. Then you have to remove all your IDE devices
from the Device Manager. The system will tell you to reboot (ours did not)
and when restarting will re-detect the controllers and set the drives up in
DMA mode.
We found that our file did not have the last two lines. We tried it, it
works, but then we already have our Hard drives set for DMA mode anyway. We
found by searching through the registry, before we tried it, that we found a
section that said we were setup for DMA mode.
More DMA setting information.
In some case you might find you are unable to make your CD/CDR/CD-RW switch
to DMA mode. This is a problem Microsoft know all about, especially with
Windows 98.
This problem is a device conflict when Windows starts up and causes the
Configuration Manager to rebalance the resources of your computer. During
this the Integrated Drive Electronics (IDE) controller input/output (I/O)
range is changed from the boot configuration to a different configuration,
but the primary and secondary controller resources are not changed properly.
So, you cannot get DMA to work with your CD drive.
What you do is, go into the Device Manager and click Hard Disk Controllers
to expand it. Double click you IDE controller. Click the Resources tab. Now,
what you need to do is UNCLICK or CLEAR the "Use Automatic Settings check
box.", so you can manually put a setting in and get it to work properly.
What you now do is change the I/O range from the current setting to a
different I/O range. Keep an eye on the box below to make sure the range you
have chosen does not conflict with any other device and then click OK. For
example, change from 1410-141f to 1060-106f.
While you are doing this check that both your Primary & Secondary
controllers are working ok, eg not showing a fault. This changing the I/O
setting and finding one that works with your system can take quite a while,
or you might be luck and find one that works first time. It is all a matter
of luck of the draw. But stick with it. The improvement in CD drive
performance with DMA is well worth the time spent fiddling here. On one of
our computers it took a long time to find an I/O range that worked. On
others a few mins. Once done remember to restart your computer and test the
CD drive.
|