Removed all old object/request/... stuff (that was crap)

1 files changed, 48 insertions, 0 deletions

diff --git a/doc/messaging.txt b/doc/messaging.txt
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index 0000000..804bb5d
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+Message passing is the technique used by processes for communicating with each other.
+It is based on a few basic functions :
+
+= msg_register =
+Registers the current process as the owner of a system channel.
+System channels are aliases for PIDs (negative PIDs resolve to corresponding real PID).
+They range from -1 to -255. They are allocated as follows :
+ from -1 to -19 : drivers
+   -1 = keyboard
+   -2 = mouse
+ from -20 to -29 : network services
+   -20 = networking subsystem (may be in several parts)
+ from -30 to -39 : system services
+   -30 = virtual file system
+   -31 = logger
+   -32 = user server
+ from -40 to -49 : UI services
+   -40 = graphic server (includes VESA driver for now)
+   -41 = sound server
+Modules for HDD drivers, network cards, sound cards, ... do not register as devices but instead
+notify of their presence to the corresponding service.
+
+= msg_send =
+Sends a message to a process. Arguments:
+- Receiver PID or system channel id
+- Message data (up to 64k bytes, minimum 4 bytes)
+The first 4 bytes of the message data always designate the message code (function).
+The kernel may intercept some special messages (as "kill process" or stuff like that).
+
+= msg_info =
+Gets first message in the queue for current process.
+Function can block waiting for a message if asked by caller and if no other function already does it.
+When it is there, return the following:
+- If a message has come
+- The sender PID
+- The message code (first 4 bytes of data)
+- The length of the data
+
+= msg_get =
+Reads the data of the first message in the queue for current process.
+Is passed a pointer where the data will be written. It is supposed that enougth memory is already allocated.
+
+From a kernel point of view, message passing is asynchronious,
+but there also are userland functions for making them look synchronious by waiting for an answer.
+Usually, message codes | 0x80000000 are answers to a message.
+
+Most processes, most of the time, will be in a loop waiting for messages to come.
+The drivers are the principal exception to that, they instead wait for an interrupt or another hardware signal.