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authorMattias Andrée <maandree@operamail.com>2014-04-27 16:54:30 +0200
committerMattias Andrée <maandree@operamail.com>2014-04-27 16:54:30 +0200
commit146ae7e11cda9a3c2b94c88dfd1f1c56d0ab7fe7 (patch)
tree7199e37ce98ac4ddbf184bd42d50c1afc9dd7d04
parentwhoops (diff)
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fix readme
Signed-off-by: Mattias Andrée <maandree@operamail.com>
-rw-r--r--README53
1 files changed, 43 insertions, 10 deletions
diff --git a/README b/README
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--- a/README
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@@ -4,16 +4,49 @@ display server with an architecture resembling that of a
microkernel.
The reason for having a display server architectured as a
-microkernel is so that components of the display server
-can be replaced online. That is, when you install a newer
-version of the display server you can start running the
-new version without having to restart the display server.
-Moreover, it allows you to replace components with your
-own versions or add new components, with exception of
-parts that need the special privileges and one special
-component, the program that starts it all, but that file
-will have no mission except restarting the master server
-if it crashes once it has started the master server.
+microkernel is so that components can be added, remove
+and replaced online. Additionally, the message passing
+between the servers makes it easy to design a system lets
+lets you make clients that can listen on messages between
+the servers and perhaps modify them. This enables you to
+do some much more with your display server. Moreover,
+if a single part of the system crashses it does not bring
+down everything, and the crahsed server can be respawned
+with minor side effects. mds is architectured in three
+layers: a microkernel, a master server and a collection
+of servers. And clients are actually located on the same
+layer as the servers, because there is no actual
+difference, the only thing that separates a server from
+a client is for what purpose you run it. mds's kernel
+is a minimal program that do initialisation of the
+display, such as giving it an index and create runtime
+files and directories for servers and other programs
+to use. Then the kernel creates a domain socket for the
+master server and spawns the master server and respawns
+it if it crashes. Because of this, if the master server
+crashes it will not lose its socket when it is respawned.
+The master server than, on its initial spawn, starts
+the all servers and other programs that the user have
+choosen and then starts accepting connections to it and
+coordinates messages between servers and clients. Further,
+separating all components into separate processes enables
+us to only give the servers the privileges they actually
+need, rather than having one program with root privileges
+that takes care of everything even things that do not do
+require any privileges.
+
+All mds's servers, that is all running parts of mds
+except the kernel, are designed so that they can re-exec
+themself so that they can be replace online without any
+side effects. Servers serialises their state saves it
+to RAM (in a directory created by the kernel), re-exec
+themself and loads their serialised state. The kernel
+cannot do this because when has spawn the master server
+it has no reasone to re-exec, its only mission is to
+respawn the master server it if would happen to crash.
+It would (probably) technically be possible to enable
+the kernel to re-exec but it is not worth it as it as
+no reason to rexec, and doing so raises some challenges.
Is this vaporware? Probably I often bored with graphical
projects. Graphics sucks.