Indirect IPC or direct IPC
voelp at os.inf.tu-dresden.de
Wed Jan 10 09:12:18 CET 2007
> Today I read the DICE Manual 3.1.0 and it talks about something about
> indirect IPC and direct IPC.
> According to my understanding it seems like this:
> indirect IPC: sender - > message buffer -> receiver
> direct IPC: sender ->sender buffer -> receive buffer ->receiver.
I assume you refer to the sections on indirect parts IPC. In the L4.V2
interface strings can be transmitted either directly or indirectly. In
the direct transmission one string can be located immediately after the
message descriptor. See the L4.V2 Ref Man in Section 2.2.4 on Messages.
The first message contains a set of dwords (dword0, 1, ...). In
addition, L4.V2 allows to copy strings in place. In this case
descriptors (string dope) point to the string to be transmitted.
In L4.V4 data can only be transmitted in the UTCBs (up to 64 words) or
as indirect strings referred to by String Items.
Technische Universität Dresden
Department of Computer Science
Institute for System Architecture
Tel: +49 (351) 463 38350
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Email: voelp at os.inf.tu-dresden.de
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