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authorDiego Nieto Cid <dnietoc@gmail.com>2011-10-30 18:00:45 -0300
committerThomas Schwinge <thomas@schwinge.name>2011-11-24 09:17:34 +0100
commit4fa5c2b40a6b91ea3956a807ba09adba28ef18cb (patch)
tree57a6f9d5a167137f4d8ed5077c4903b1ebf7518b /hurd
parentb5e48137f69574cc6396d9c0d143a4ce83f06378 (diff)
id:"20111030210045.GA4983@myhost".
Diffstat (limited to 'hurd')
-rw-r--r--hurd/console.mdwn85
-rw-r--r--hurd/libports.mdwn12
2 files changed, 96 insertions, 1 deletions
diff --git a/hurd/console.mdwn b/hurd/console.mdwn
index 4f976efd..e9daa96e 100644
--- a/hurd/console.mdwn
+++ b/hurd/console.mdwn
@@ -1,3 +1,88 @@
+[[!meta copyright="Copyright © 2002, 2003, 2004, 2005, 2006, 2007, 2009, 2011
+Free Software Foundation, Inc."]]
+
+[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
+id="license" text="Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License, Version 1.2 or
+any later version published by the Free Software Foundation; with no Invariant
+Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license
+is included in the section entitled [[GNU Free Documentation
+License|/fdl]]."]]"""]]
+
+The Hurd console's implementation is broken into two pieces each running on
+it's own process, the console client and server.
+
+The console server is also splitted into modules (input driver, display driver,
+speaker, ...) but they all run in the same process.
+
+The console server puts itself as a translator on top of `/dev/vcs` folder
+presenting the following hierarchy:
+
+ + /dev/vcs
+ \
+ +- 1
+ \
+ +- console
+ +- input
+ +- display
+ +- ..
+ +- n
+
+where the numbered nodes represent virtual consoles and their contents are all
+alike.
+
+As the following graph shows, the console, input and display nodes are the
+interfaces used by the terminal server, input driver and display drivers
+respectively.
+
+ +------------------+ +-----------------+
+ | Input driver | | Terminal Server |
+ | | | |
+ | pc-kbd | | |
+ +------------------+ +-----------------+
+ | _cons_vcons_input |
+ | writes to reads |
+ | vcs/i/input vcs/i/console |
+ | +-----------------+ |
+ | | Console Server | |
+ | | /hurd/console | |
+ | input_enqueue | --------------- | input_dequeue |
+ +--------------->| Input Queue |>---------------+
+ | --------------- |
+ +--------------->| Output Buffer |>---------------+
+ | +-----------------+ |
+ | |
+ | writes reads |
+ | vcs/i/console vcs/i/display |
+ | |
+ +----------------+ +-----------------+
+ | Teminal Server | | Display driver |
+ | | | |
+ | /hurd/term | | vga |
+ +----------------+ +-----------------+
+
+The input driver takes scancodes from the in-kernel kbd queue, translates them
+into characters and writes them to the input node. Then the terminal server
+reads the console node taking the characters out of the console server.
+
+Each of theese actions is actually an RPC handled by the translator on
+`/dev/vcs`. Writes to input nodes are handled by calling `input_enqueue` to
+put the character into a queue. And reads from console nodes are handled by
+calling `input_dequeue` which takes out charecters from the queue and gives
+them to the reader.
+
+It's important to note here that both `input_enqueue` and `input_dequeue` are
+blocking operations and a blocked `input_dequeue` necessarily needs an
+`input_enqueue` call to continue.
+
+[[RPC]]s are handled by the console server with the help of [[hurd/libports]]'
+`ports_manage_multithreaded` API.
+
+
+---
+
+/!\ old content; [[!taglink open_issue_documentation]]: cleanup needed.
+
The below is a reworked version of Marcus Brinkmann's [letter to the debian-hurd list](http://lists.debian.org/debian-hurd/2002/debian-hurd-200209/msg00054.html). It describes how to setup the new console server for the Hurd. I am testing this right now, so this document is a work in progress.
-- [[Main/JoachimNilsson]] - 21 Jan 2003
diff --git a/hurd/libports.mdwn b/hurd/libports.mdwn
index 28274338..0ec0596c 100644
--- a/hurd/libports.mdwn
+++ b/hurd/libports.mdwn
@@ -1,4 +1,4 @@
-[[!meta copyright="Copyright © 2010 Free Software Foundation, Inc."]]
+[[!meta copyright="Copyright © 2010, 2011 Free Software Foundation, Inc."]]
[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
id="license" text="Permission is granted to copy, distribute and/or modify this
@@ -18,3 +18,13 @@ provide an interface independently of the underlying [[microkernel]].
*libports* does not itself depend on *[[libthreads]]*, but the appropriate
threading hooks are used if present, that is if *[[libthreads]]* is used by
another component.
+
+
+# Message Processing
+
+## `ports_manage_multithreaded`
+
+When a message is recieved, the thread acting as receiver checks if any other
+thread is also waiting for requests. If there is none, a new thread is
+spawned. Thus, the current thread continues processing the message while the
+newly created thread starts listening for new ones.