Version
control
is
a
system
that
records
changes
to
a
____________________
or
set
of
files
over
time
so
that
you
can
recall
specific
____________________
later
.
For
the
examples
in
this
book
you
will
use
software
source
____________________
as
the
files
being
version
controlled
,
though
in
reality
you
can
do
this
with
nearly
any
type
of
file
on
a
____________________
.
The
need
for
a
____________________
way
to
organize
and
control
revisions
has
existed
for
almost
as
long
as
writing
has
existed
,
but
____________________
control
became
much
more
important
,
and
complicated
,
when
the
era
of
____________________
began
.
The
numbering
of
book
editions
and
of
specification
revisions
are
examples
that
date
back
to
the
____________________
-
only
era
.
Today
,
the
most
capable
(
as
well
as
complex
)
revision
control
systems
are
those
used
in
____________________
development
,
where
a
team
of
people
may
change
the
same
files
.
Version
control
systems
(
____________________
)
most
commonly
run
as
stand
-
alone
____________________
,
but
revision
control
is
also
embedded
in
various
types
of
software
such
as
____________________
processors
and
spreadsheets
,
collaborative
web
docs
and
in
various
content
____________________
systems
,
e
.
g
.
,
Wikipedia's
Page
history
.
Revision
control
allows
for
the
ability
to
____________________
a
document
to
a
previous
revision
,
which
is
critical
for
allowing
editors
to
track
each
other's
edits
,
correct
mistakes
,
and
defend
against
____________________
and
spamming
.
Audit
trail
The
following
features
are
commonly
part
of
a
change
management
____________________
procedure
:
Change
management procedures
are
formally
documented
and
controlled
.
Changes
are
requested
in
a
____________________
process
:
____________________
are
recorded
and
stored
for
reference
.
The
effect
of
the
requested
change
is
____________________
:
Each
change
is
assessed
based
on
its
projected
effect
to
the
computer
system
and
business
operations
.
The
assessment
is
____________________
with
the
request
.
Priority
is
based
on
____________________
,
potential
benefits
,
and
the
ease
with
which
changes
can
be
corrected
.
Controls
are
imposed
on
changes
:
Changes
are
limited
by
____________________
or
manual
controls
.
In
particular
,
unauthorized
changes
are
periodically
searched
for
.
An
emergency
change
process
is
in
place
.
:
____________________
clearly
define
emergency
changes
.
Generally
,
these
are
errors
that
significantly
impair
system
function
and
business
operations
,
increase
the
system's
vulnerability
,
or
both
.
Emergency
changes
override
some
,
but
not
all
,
controls
.
For
instance
,
a
proposed
change
might
be
documented
,
but
not
____________________
without
authorization
.
Change
documentation
is
____________________
updated
.
Maintenance
tasks
and
changes
are
recorded
.
Controls
are
applied
to
____________________
:
For
security
,
new
software
releases
often
require
controls
such
as
back
ups
,
version
control
,
and
a
secure
implementation
.
Software
distribution
is
assessed
for
____________________
:
Software
distribution
is
assessed
for
compliance
with
license
agreements
.
____________________
can
have
disastrous financial and
legal
results
.
Changes
are
submitted
for
approval
:
Proposed
changes
are
submitted
for
approval
after
____________________
have
reviewed
the
required
resources
,
other
changes
,
the
effect
,
urgency
,
and
the
system's
stability
.
Duties
are
separated
:
Responsibility
for
creation
,
approval
,
and
application
are
assigned
to
different
personnel
to
avoid
undesired
changes
.
Changes
are
reviewed
:
Changes
are
monitored
to
assess
the
efficacy
of change
____________________
.
