Messages in this thread | | | From | "Stephen C. Tweedie" <> | Date | Wed, 16 Jun 1999 16:23:02 +0100 (BST) | Subject | Re: ncd (network character device) ? |
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Hi,
On Wed, 9 Jun 1999 11:03:27 +0200, Gabor Lenart <lgb@oxygene.terra.vein.hu> said:
> Is there any patch or plan to implement network char. device like nbd > for block devices ?
Supporting networked character devices is hopelessly complex. Some char devices have strange mmap() requirements that you just cannot do over the network. All of them have ioctl()s, in which the ioctl handler in the driver pokes around in user memory in unpredictable patterns: there is no certain way to tell whether the accesses will be reads or writes, and how much memory is touched. Marshalling all of that over the network wouldd be a nightmare: you would have to special-case just about every ioctl, and the mmap() stuff will never work (think about /dev/mem framebuffers for an example).
--Stephen
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