Re: problems increasing SG_BIG_BUFF

Douglas Gilbert (dgilbert@interlog.com)
Wed, 30 Jun 1999 08:36:02 -0400

abel deuring wrote:
>
> Hi all!
>
>
> This suggests that most if not all scanner carriage stops can be avoided
> if consecutive reads commands are sent to the scanner as soon as
> possible after the data from the previous command has been read in.
>
> Doug, what do you think about adding ioctl-calls to the SG driver which
> implement queueing of asynchrounous SCSI commands?

Abel,
Command queuing is already there but turned off by
default (because cdparanoia got upset when it found
it :-) ). It is demonstrated in a program called
sgq_dd512 (a "dd" variant) that can be found on
sg's home page in the utility tarball.

See the SG_SET_COMMAND_Q ioctl(). I was not aware
that many scanners supported command queuing.

Doug Gilbert

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