Jason: In this lesson,
we're going to talk about inaccurate system date and time.
Now, when it comes to inaccurate system date and time,
almost exclusively from a hardware perspective
this is going to be caused
by a battery failing on your motherboard.
Now, every motherboard has a small battery
that helps to keep its RTC or real time clock in sync.
This is because when you shut down your computer
you're removing power to it
and this real time clock needs to have power
to remember what the date and time was
that you set on that particular system.
In modern computer systems,
these are most commonly going to be a lithium coin cell battery
that is going to take the form factor of a CR2032.
Now, the CR 2032 looks like a watch battery, essentially,
and they usually last somewhere between three to five years.
And so if you're somebody who keeps a computer longer
than about three to five years, you may start to have issues
with the date and time of your system
where when you shut down the computer
and you bring it back online,
it forgets what the date is
or the time starts slipping either forward or backwards.
Now, luckily for us these days,
most of our modern operating systems
do set their date and time automatically over the internet
by talking to a centralized network time protocol server.
But if you're not connected to the internet
you are going to notice this date/time creep that occurs
and generally this is going to be
because the battery has died on your motherboard.
So why is time so important to us
on a computer that we have to have its own battery
on the motherboard to protect it?
Well, this all comes down to the fact
that time keeping needs to be done accurately
for a wide variety of things on our systems,
including the creation date of files and directories,
being able to communicate to other computers
over the network or over the internet
because a lot of our authentication relies
on a time based signature protocol,
and so if we're not all using the same type of time,
this can actually cause issues
and you won't be able to connect
to servers and other things like this.
And so it's really important that you make sure the time
is accurate on your system within a couple of minutes,
and that the system can remember that time
whenever you remove power from it.
Now, I mentioned that most motherboards are going to be
using a small circular coin size battery
that is called a CR2032.
This does depend on your make and model of motherboard
and so check your motherboards documentation
to ensure you're getting the right battery
for your motherboard.
On some older systems,
they didn't use these coin style batteries,
and instead they used the battery
that actually looked like a computer chip
that would actually be plugged into the motherboard.
And so these were very specific,
and made by each individual motherboard manufacturer
and you'd have to buy it from them.
Thankfully, over time,
we kind of got to this standard system
of these coin type batteries of the CR2032s
that are used across most motherboards.
Now, another major change we've seen over time is
that we've moved from what's called a CMOS into NVRAM
for being able to store the bios and UEFI data.
Now, in the old days,
we had this thing called CMOS, which stands for
the complimentary metal-oxide-semiconductor,
and this described the manufacturing process
that was used to create this type of of memory.
This memory, though had to constantly be refreshed
inside of it, otherwise we would lose the settings.
And to do that when the power was removed from the system,
it would rely on this battery
in the motherboard to be able to keep power
to that CMOS and ensure that those settings weren't lost.
Now, over time, this CMOs was actually replaced
with something called NVRAM,
which stands for non-volatile ram.
Now, on these modern motherboards that use NVRAM
or non-volatile RAM,
these things can actually store the data
without having to be constantly refreshed.
You can remove power from it
and it will still remember everything you stored there.
Essentially, think about it like your USB flash drives
or your solid state devices.
These things are also made out of NVRAM,
and so when you remove power from them,
the data still remains.
Now, in the older CMOS, that was not the case
and so these batteries were vitally important
because if that battery died on you,
you would lose not just your date and time,
but also all of your settings that you create
inside your bios, including your bios passwords
your storage device settings, and things like that.
So back then,
it was really important to make sure you had a good battery
on your motherboard to hold not just the date and time,
but also all of these settings
inside the bio or UEFI inside of your CMOS.
All that being said, for the exam, I want you to remember
that there is a battery on your motherboard
and anytime you start having date or time issues,
it could actually be tied to the fact
that that battery is now out of power
and it has died and needs to be replaced.
Also, when you talk about this battery
a lot of people will call this a CMOS battery.
Technically, that's not accurate anymore
because we don't really use CMOS.
We use NVRAM.
But on the exam,
if you see a question that mentions the CMOs battery
or the real time clock battery,
we're really talking about the same thing here
when we're talking about that CR2032
and it's the current standard on most modern motherboards.