[Info-vax] QIO Writes to a mailbox

[Johnny Billquist]

On 2011-11-07 15.50, Bob Koehler wrote:
> In article<j932ro$42j$1 at Iltempo.Update.UU.SE>, Johnny Billquist<bqt at softjar.se>  writes:
>>
>> It is possible for drivers to have pre-queueing hooks invoked. Those
>> could in theory also copy the data somewhere.
>
>     Generally, buffered I/O devices copy outgoing data to a system
>     buffer dureing the FDT routines, which are before $QIO returns.
>
>     But, of course, direct I/O devices do not, and any individual
>     driver can do it's own thing, so it's a bad idea to assume knowledge
>     of what goes on under the covers of $QIO unless you wrote the code.

Indeed. Which is probably the basic point I've tried to make the whole time.

	Johnny