[Info-vax] QIO Writes to a mailbox

[George Cornelius]

I wrote:
> It is not clear to me what it is about a QIO to a full mailbox that should make
> the entire process go unresponsive.  Mailboxes are already quite limited, so we
> generally cannot work around a size issue by making the mailbox have more quota.
> It would seem, then, that the least that could be done would be to invent a
> modifier to allow the I/O to just remain queued until space became available,
> realizing, of course, that interesting things could happen if such a pending
> I/O were cancelled when there were others queued behind it.

To answer my own question: it's _buffered_ I/O, not half buffered,
half direct.  If its data cannot be copied to nonpaged dynamic
memory it must either fail or hang.

George