Windows System Software -- Consulting, Training, Development -- Unique Expertise, Guaranteed Results

Before Posting...
Please check out the Community Guidelines in the Announcements and Administration Category.

More Info on Driver Writing and Debugging

The free OSR Learning Library has more than 50 articles on a wide variety of topics about writing and debugging device drivers and Minifilters. From introductory level to advanced. All the articles have been recently reviewed and updated, and are written using the clear and definitive style you've come to expect from OSR over the years.

Check out The OSR Learning Library at:

Few questions regarding RIO

EmjayenEmjayen Member Posts: 1

The documentation for RIOSend states that an in-flight buffer cannot be referenced by more than one tx operation concurrently; is this really true? If so, could it be explained as to why? I have a lot of software which relies on the absence of such a restriction as is the case with the usual I/O API.

Additionally, is there any plan to support SGIO with RIO? It appears such is intended given the presence of the familiar count when specifying the number of supplied buffers, however this is restricted to 1 at present.

Note that, I understand RIO is beyond the scope of ntdev in general given it's just a userland API, however I've exhausted all other options for information regarding this still rather esoteric API and I'm aware there's a few MS/NDIS team members around here who, if anyone, would know.




  • MBond2MBond2 Member Posts: 184

    RIO is just about the same as regular IO except that the UM application designates memory regions that get pinned into RAM and so cannot be paged out an certain locks can be elided when making read / write calls.

    Obviously you would not pass the exact same buffer to two concurrent ReadFile calls. The same is true with RIO.

    WriteFile is more interesting as there is no API level guarantee that the buffer will be const, but many applications would break if the kernel modified data buffers as they are written

Sign In or Register to comment.

Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Upcoming OSR Seminars
OSR has suspended in-person seminars due to the Covid-19 outbreak. But, don't miss your training! Attend via the internet instead!
Internals & Software Drivers 30 Nov 2020 LIVE ONLINE
Writing WDF Drivers 7 Dec 2020 LIVE ONLINE
Developing Minifilters Early 2021 LIVE ONLINE