From: "James Sparenberg" <[EMAIL PROTECTED]> > On Tue, 2003-11-18 at 03:32, Angelo Naselli wrote: > > So there isn't any problem is it? > > I saw this thing because of a system that seems to be > > slower and with more hd access so i assumed the > > message > > > > ide: Assuming 33MHz system bus speed for PIO modes; > > override with idebus=xx > > > > as something wrong on my system. > > No problem. You might try doing hdparm -m 32 to see if it speeds up > disk access. But the reference to PIO mode would only affect you > directly if you had some really old HDD's or CD drives on the box. The > PIO IDE bus and the UDMA IDE bus are "different" (Although I don't have > all of the details on the difference.) and you use one but not the > other. >
Actually the bus is the same, it's only the data flow protocol on the bus that changes... running the bus in pio mode means that your cpu workload will get high since it has to "be in charge" of moving all the data to and from ram... but when the bus is running dma, the data from the hdd to ram will bypass your cpu (and leave it free for other work) and rely an the dma controller to make sure the data gets to/from ram. going from dma to udma adds crc32 checking to the transfers, thus enabling higher transfer speeds without transfer errors ... So, in short... to gain full speed from a pio hdd, your cpu will run with 60-99% workload, whereas running udma will keep it around 3-5% ( of course your might see different values, but this was only a generic example) -- Regards Thomas
Want to buy your Pack or Services from MandrakeSoft? Go to http://www.mandrakestore.com
