On Tue, 20 Jul 2004 10:27:57 -0700 Shesha Sreenivasamurthy <shesha@xxxxxxxxxxx> wrote: Hi Shesha, > I am having trouble with O_DIRECT. Trying to read or write from a block > device partition. > > 1. Can O_DIRECT be used on a plain block device partition say > "/dev/sda11" without having a filesystem on it. yes. > 2. If no file system is created then what should be the softblock size. > I am using the IOCTL "BLKBSZGET". Is this correct? yes. > 3. Can we use SEEK_END with O_DIRECT on a partition without filesystem. yes. I'm using these exact things in an application. Note that with 2.4 kernels the "granularity" you can use for offset and r/w size is the softblock size (*). For 2.6 the requirements are much more relaxed: it's the device blocksize (typically 512 byte). (*): actually one of offset or r/w size has a smaller minimum if I remember correctly. Don't remember which one. But if you assume the softblock size as a minimum for both you're allways safe. greetings, Rob van Nieuwkerk -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
