XZ81 is an emulator of the Sinclair ZX81 computer running on Unix systems. It has been written by Russell Marks in 1995.

Here is a port on GP2X of the version 2.1 that ZX-81 had previously ported to PSP.

http://zx81.zx81.free.fr/serendipity/index.php?/archives/170-guid.html