Steem is a well known Atari ST emulator. It used to be the best ST emulator.
Its development was stopped in 2004, at v3.2. The Steem authors probably got
sick of all the lamers.
Since then, it has remained the best ST emulator with respects to "gameplay",
but other ST emulators like Hatari and SainT are trying to usurp Steem's
In 2011 the Steem authors (Hayward bros) released the source code for further
Steem SSE is a new version of Steem based on this release. It incorporates
new features, some of them based on the Hatari emulator, some on various
internet discussions and documentation.
Steem SSE aims to become the #1 STF/STE emulator. There's no limitation in
the original Steem structure that would make that goal unreachable.