.Dd February 22, 2021
.Dt OPERATING-SYSTEMS 7
.Os "Causal Agency"
.
.Sh NAME
.Nm Operating systems
.Nd criteria
.
.Sh DESCRIPTION
Sometimes in conversation
I use the term
.Dq real operating system
which people,
perhaps rightfully,
take as inflammatory.
But I have actually thought about
what I mean when I say
.Dq real operating system
and come up with
this list of criteria.
.
.Pp
An operating system should be...
.Bl -bullet
.It
Consistent and cohesive:
all parts of the system should have similar
usage, configuration, documentation and so on.
Parts of the system should naturally work together,
because they were designed to do so.
.
.It
Documented:
the system should include its own documentation.
A user should not have to
search some external wiki
to learn how the system works.
It should be obvious
where to find documentation
on a particular topic.
.
.It
Programmable:
the system should provide
a way to program the computer.
A computer which cannot be programmed
is not a computer at all.
Usually this takes the form
of a C compiler
and the tools that go with it.
In earlier times,
it might have been
a BASIC interpreter.
.
.It
Examinable and modifiable:
the full source tree
for the system should be included,
or easily obtainable
through official means.
A user should have no trouble
finding the corresponding source
for a part of the system.
Together with the previous point,
the source tree should be
compiled by the included toolchain,
allowing local modification.
.El
.
.Pp
Some things that may be parts
of real operating systems,
but are not themselves operating systems:
a kernel,
a package manager,
a collection of packages.
.
.Pp
I will leave it as an
.Dq exercise for the reader
to guess which operating systems
meet these criteria
and which don't.
.
.Sh AUTHORS
.An june Aq Mt june@causal.agency