diff --git a/realtime/OpenOS/usr/lib/realtime.lua b/realtime/OpenOS/usr/lib/realtime.lua
new file mode 100644
index 0000000..033c9ad
--- /dev/null
+++ b/realtime/OpenOS/usr/lib/realtime.lua
@@ -0,0 +1,22 @@
+local computer = require "computer"
+local realtime = {}
+realtime.epoch, realtime.uptime, realtime.offset = 0, computer.uptime(), 0
+
+function realtime.update(epoch,uptime,offset)
+ if type(epoch) ~= "number" or type(uptime) ~= "number" then
+  return false
+ end
+ realtime.epoch, realtime.uptime, realtime.offset = epoch, uptime, offset or realtime.offset
+ return true
+end
+
+function realtime.time(utc)
+ local ofs = realtime.offset
+ if utc then
+  ofs = 0
+ end
+ local ut = computer.uptime()
+ return (realtime.epoch+(ut-realtime.uptime))+ofs
+end
+
+return realtime
diff --git a/realtime/OpenOS/usr/man/realtime b/realtime/OpenOS/usr/man/realtime
new file mode 100644
index 0000000..2e65182
--- /dev/null
+++ b/realtime/OpenOS/usr/man/realtime
@@ -0,0 +1,13 @@
+# realtime
+
+realtime is a library for OpenOS providing a reasonably accurate current real-world time, given the right input (see realtime-sync and realtime-relay).
+
+## API
+
+### realtime.time(*utc*)
+
+Returns the current time, either respecting the current offset, or if *utc* is set, with no offset.
+
+### realtime.update(*epoch*, *uptime*, *offset*)
+
+Updates the currently known real time, with the time as *epoch*, measured at *uptime*. Optionally, an offset can be provided.