1 files changed, 35 insertions, 0 deletions

diff --git a/overview.rst b/overview.rst
new file mode 100644
index 0000000..e3a60e8
--- /dev/null
+++ b/overview.rst
@@ -0,0 +1,35 @@
+Overview
+--------
+
+EUMEL is different from conventional operating systems in a lot of ways. Some
+of them were neccessary due to hardware constraints at that time and others
+were deliberatly designed this way. EUMEL’s key features are:
+
+Hardware independence
+    The OS has *two* hardware abstraction layers, significantly improving its
+    portability. The first one, Software/Hardware (SHard), provides functions
+    for a concrete machine, such as the Olivietti M20, Amiga ST or IBM PC
+    AT/XT.  EUMEL0 (Urlader), the second layer, implements a virtual machine on
+    top of a specific processor architecture like Z80 or x86. Programs are
+    compiled into bytecode for this machine and thus independent of the actual
+    machine they are running on.
+Single-level store
+    Every object (dataspace) lives in a single, virtual address space. The
+    memory is organized into pages, which can reside in memory or on disk.
+    The operating system transparently moves pages to disk if they have not
+    been in use lately and reads them back as soon as a process requests it
+    ([praxis2]_, p. 82).
+Copy on write
+    Pages are shareable and EUMEL automatically unshares them if one copy is
+    written to.
+Persistence
+    Every file and every task is a dataspace. Since they all reside in the
+    single-level store the machine can powered off and back on again, with all
+    tasks starting from the point where they left off.
+Time-sharing and multi-user
+    A single machine running EUMEL is capable of serving multiple “thin
+    clients” connected via serial lines.
+One-language concept
+    *ELAN (Elementary Language)* is system implementation language, programming
+    language, shell language and documentation language.
+