[Info-vax] QIO Writes to a mailbox

[JF Mezei]

Bob Koehler wrote:

>    However, the behaviour inside the driver is not part of a documented
>    API and could change with the next minor patch you install.


Generic question about all write operations with QIO:

There are generally 2 write option codes. IO$M_WRITEVBLK and another one
whone nomenclature escapes me at the moment. Would those made a formal
"documented" behaviour with regards to garanteed copying of the user
buffer into a driver/device buffer during the SYS$QIO ?


I realise that for a read, it is quite different.

Now, for a non generic question about TCPIP :


Consider TCPIP. When you write data, you are not garanteed that this
data goes out in its own packet. It may be combined with some previously
issued writes or may wait until there are other writes made. Doesn't
that behaviour pretty much require that the driver make copies of the
data in its internal buffers so that you can then reuse your own buffer
to issue subsequent writes ? (which allows the driver to then combine
writes to make larger more efficient TCP packets) ?