[comp.sys.hp] What? No full duplex transparent serial I/O on MPE/XL??

campbell@redsox.bsw.com (Larry Campbell) (12/22/89)

We're trying to implement (port, actually) a networking product on MPE/XL.
It's hard for me to believe (this is 1989 after all) but it appears that
there is no way to do full duplex fully transparent asynchronous I/O with
MPE/XL.  Is this really true, or are there magic words we lack?

The major problems are (1) can't do a write while a read is pending without
first aborting the read, (2) the DTC wants to do XON/XOF flow control and we
don't know how to tell it not to, (3) even if we got the XON/XOF to shut
up, we suspect the DTC will drop the data on the floor -- it XOFs after
only about 200 bytes.  We want to use ~2K byte messages.

Are we missing something, or is serial I/O under MPE/XL just hopeless?
-- 
Larry Campbell                          The Boston Software Works, Inc.
campbell@redsox.bsw.com                 120 Fulton Street
wjh12!redsox!campbell                   Boston, MA 02109