make keyboard work a bit

report/kernel.tex

@@ -269,16 +269,37 @@ registers and possibly other information which is different per Thread.
 \item Let Iris schedule the next process.  This is not thread-specific.
 \item Get the top Memory object.  This is not thread-specific.  Most Threads
 are not allowed to perform this operation.  It is given to the initial Threads.
-They can pass it on to Threads that need it (mostly device drivers).
+They can pass it on to Threads that need it (if any).
 \item In the same category, register a Receiver for an interrupt.  Upon
 registration, the interrupt is enabled.  When the interrupt arrives, the
 registered Receiver gets a message from Iris and the interrupt is disabled
 again.  After the Thread has handled the interrupt, it must reregister it in
 order to enable it again.
+\item Allocate a range of contiguous physical memory.  This is only relevant
+for device drivers whose device will directly access the storage, such as the
+display driver.  The result of this call is that the memory is counted as used
+by the Thread, and it is reserved, but it is not returned.  Instead, the
+address of physical memory is returned, and the pages need to be retrieved with
+the next operation.  This capability is not present in normally created
+threads.
+\item Allocate a page of physical memory.  This is used in combination with the
+previous operation to reserve a block of physical memory, and by device drivers
+to map I/O memory into their address space.  There is a flag indicating whether
+this memory should be freed (ranges) or not (I/O).  Users of this operation are
+trusted to handle it properly; no checks are done to ensure that no kernel
+memory is leaked, or that the allocated memory isn't used by other threads or
+the kernel.  Of course, this capability is not present in normally created
+threads.
+\item Get the physical address of a page.  Only device drivers need to know the
+physical address of their pages, so this operation is not available on normal
+threads.
 \item And similarly, allow these priviledged operations (or some of them) in an
 other thread.  This is a property of the caller, because the target thread
 normally doesn't have the permission to do this (otherwise the call would not
-be needed).  The result of this operation is a new Thread capability with all specified rights set.  Normally this is inserted in a priviledged process's address space during setup, before it is run (instead of the capability which is obtained during Thread creation).
+be needed).  The result of this operation is a new Thread capability with all
+specified rights set.  Normally this is inserted in a priviledged process's
+address space during setup, before it is run (instead of the capability which
+is obtained during Thread creation).
 \end{itemize}
 
 \subsection{Page and Cappage}
@@ -317,4 +338,14 @@ Operations or capability objects:
 \item Get a copy of the capability.
 \end{itemize}
 
+\section{Interface classes}
+Around Iris is a system of some programs to create the operating system.  These
+include the device drivers.  While Iris itself needs no specific interfaces
+from them, some interface classes are defined, which are used by the default
+environment.  By defining classes, it is possible to let a program use any
+device of that type without needing changes to its code.
+
+These definitions are in the source.  A copy of the information here would only
+lead to it getting outdated.
+
 \end{document}