<s>
SIMH	B-Application
is	O
a	O
free	B-License
and	I-License
open	I-License
source	I-License
,	O
multi-platform	O
multi-system	O
emulator	B-Application
.	O
</s>
<s>
SIMH	B-Application
was	O
based	O
on	O
a	O
much	O
older	O
systems	O
emulator	B-Application
called	O
MIMIC	O
,	O
which	O
was	O
written	O
in	O
the	O
late	O
1960s	O
at	O
Applied	O
Data	O
Research	O
.	O
</s>
<s>
SIMH	B-Application
was	O
started	O
in	O
1993	O
with	O
the	O
purpose	O
of	O
preserving	O
minicomputer	B-Architecture
hardware	O
and	O
software	O
that	O
was	O
fading	O
into	O
obscurity	O
.	O
</s>
<s>
In	O
May	O
2022	O
,	O
the	B-License
MIT	I-License
License	I-License
of	O
SIMH	B-Application
version	O
4	O
on	O
GitHub	B-Application
was	O
unilaterally	O
modified	O
by	O
a	O
contributor	O
to	O
make	O
it	O
non-free	B-Application
,	O
by	O
adding	O
a	O
clause	O
that	O
revokes	O
the	O
right	O
to	O
use	O
any	O
subsequent	O
revisions	O
of	O
the	O
software	O
containing	O
their	O
contributions	O
if	O
modifications	O
that	O
"	O
influence	O
the	O
behaviour	O
of	O
the	O
disk	O
access	O
activities	O
"	O
are	O
made	O
.	O
</s>
<s>
As	O
of	O
27	O
May	O
2022	O
,	O
Supnik	O
no	O
longer	O
endorses	O
version	O
4	O
on	O
his	O
official	O
website	O
for	O
SIMH	B-Application
due	O
to	O
these	O
changes	O
,	O
only	O
recognizing	O
the	O
"	O
classic	O
"	O
version	O
3.x	O
releases	O
.	O
</s>
<s>
On	O
3	O
June	O
2022	O
,	O
the	O
last	O
revision	O
of	O
SIMH	B-Application
not	O
subject	O
to	O
this	O
clause	O
(	O
licensed	O
under	O
BSD	B-Operating_System
licenses	I-Operating_System
and	O
the	B-License
MIT	I-License
License	I-License
)	O
was	O
forked	B-Application
by	O
the	O
group	O
Open	O
SIMH	B-Application
,	O
with	O
a	O
new	O
governance	O
model	O
and	O
steering	O
group	O
that	O
includes	O
Supnik	O
and	O
others	O
.	O
</s>
<s>
The	O
Open	O
SIMH	B-Application
group	O
cited	O
that	O
a	O
"	O
situation	O
"	O
had	O
arisen	O
in	O
the	O
project	O
that	O
compromised	O
its	O
principles	O
.	O
</s>
<s>
SIMH	B-Application
emulates	B-Application
hardware	O
from	O
the	O
following	O
companies	O
.	O
</s>
