> On Tue, 23 Oct 2001, Der Herr Hofrat wrote: > > > > Hi all. This is a bit peripheral to rtlinux, but hopefully someone here can > > > help me out. > > > > > > I have written a data acquistion application using an rtlinux module, > > > and, while everything works well when I am not saving data to disk, during disk > > > writes I get pauses in the display. This is, as far as I understand it, a > > > result of disk write buffering, and I'm wondering if there is anything I can do > > > about it. > > > > make shure your disk is in dma-mode (hdparm -d /dev/hd# to check , hdparm -d 1 >/dev/hd# to set) if its in pio mode then the box will crawl on heavy writes. > > > > depends also on the data amount that you need to write - but you could consider >writing compressed output if its a lot - compressed output can improve the overall >performance a lot as the disk normaly is the bottle neck (unless you have a > > glowing 80MByte/s SCSI palte in there). > > > > Thanks for your reply. I will check the dma mode. I need to write large amounts > of data (up to at least a few GB over a couple of hours), so I don't think the > ramdisk option would work well. I'll think about the compression idea, though. > How would you recommend implimenting that? > if you download zlib (I think 1.1.3 is current) there are some example programs in there basically it's no more than calling compress() during data write and uncompress() from some data-read app on any char* that you pass.
hofrat -- [rtl] --- To unsubscribe: echo "unsubscribe rtl" | mail [EMAIL PROTECTED] OR echo "unsubscribe rtl <Your_email>" | mail [EMAIL PROTECTED] -- For more information on Real-Time Linux see: http://www.rtlinux.org/
