How to Reformat a Disk
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So formatting a hard disk. It's something
that I think a lot of us take for
granted but not everybody really knows
how to do.
Let me show you. In fact I'm going to
show you four different ways
to reformat your hard drive. So here we
are in Windows 10
home I'm firing up Windows file explorer
and down here you'll see I've got this
little one gigabyte
that's a USB thumb drive. I'll right
click on it
and click on of all things format.
Format then gives me some options. It's
worth going through what some of these
options may or may not be
on your particular device whatever it is
you're formatting.
The capacity is what it is. It's
generally the capacity of this device.
Like I said, this is a one gigabyte
thumb drive so it's going to be
available as 956 megabytes after all the
overhead is removed.
We have some options in terms of file
systems. This actually has the longest
list of options that I've actually seen.
FAT is the default for something this
small. FAT32
is a great alternative for larger
devices
that are intended to be shared across
multiple
non-window devices so for example if you
were formatting an sd card to be used in
your camera or your cell phone
exFAT would be the way to go NTFS
on the other hand is a good alternative
for
internal drives or for external hard
drives
that are large-ish that you want the
full range of NTFS features including
bitlocker or permissions or
it's also a little bit faster on some
devices so NTFS is an option
when you're not sure just accept the
default that's fine
uh you can see it's actually called out
both FAT and FAT32
this device is small enough that it
doesn't need FAT32.
FAT16 also just plain old FAT. It's
perfect for a one gigabyte drive
allocation unit size. This is an
interesting one
on FAT there really aren't that many
options on NTFS there are a bunch
on some of the other formats there's a
difference the issue here
is essentially when you write data to a
file it's not
actually allocated according to the size
of the file the space on the disk isn't
allocated that way
it's allocated in chunks and what we're
saying here is how big should those
chunks be
so on this drive for example with the
default of 16 kilobytes for an
allocation size
a one byte file is going to take up 16
kilobytes it's
going to use or have allocated to it 16
kilobytes of disk space
now everything under 16 kilobytes will
also it'll just
be that 16 kilobytes when you then
exceed 16 kilobytes you get 16 kilobytes
and one well it has to allocate then
another chunk of 16 kilobytes
like I said the choices vary depending
on
how you're planning on using this device
which are available
which allocation unit sizes are
available for the format you've selected
whether you're going to have lots and
lots of small files versus like one or
two really big files
how many files you're going to have in
total all of these
can factor into this decision it's not
necessarily an
easy one unless you really have a good
idea of the criteria that you're looking
for
that's why once again I'm going to
suggest that unless you have specific
criteria that you're trying to target
except the default which in this case is
16 kilobytes
if you've been playing around by the way
say we said 64 kilobytes or we changed
it to like
exFAT we went back to 32
kilobytes whatever if you want to go
back to the device defaults just hit
that button and it will basically make
its recommendations once again the
volume label
that's just the text that appears here
and shows up on directory listings in
the command prompt
I'm going to go ahead and change this to
example just so that we can see that
this is one way to change that
and have it be set to something other
than whatever the device came with
if there's one at all. Quick format. I'm
going to do that
but when we do we're going to get a
warning first.
We're about to erase all the data on
this disk and that's something that I
think you really really need to
understand about formatting.
By definition formatting
means to erase everything that's on the
drive.
That means that whatever is there now
won't be there when we're done.
That's typically what we want. That's
typically why we format a drive and in
fact
a quick format is probably the fastest
way to erase
everything on a drive that's full of
stuff. So I'm going to go ahead and hit
OK.
And we're done. Quick formatting really
is pretty quick.
Now when we uncheck quick format we're
going to perform what's called a
full format. The difference is
important to understand. With a quick
format
all that really happens is the
formatting software
sets up the structures the data
structures
on the disk that track where files will
live. There are no files so it's setting
up empty data structures but it's just
basically setting up a directory that
says
"yep this disk is empty it's got no files."
But it's not doing anything to the rest
of the drive.
If we do a full format what it's going
to do first.
I'm going to go ahead and kick it off
here once again. It's going to warn us
and we're going to click ok.
If we do a full format what it's going
to do
is very carefully very methodically
it's going to go through and overwrite
everything on that drive. As you can see
it's already taken longer than the quick
format.
It'll take a few minutes for this one
gigabyte external drive. It's a
USB 2 thumb drive. It's an old one I had
laying around for example purposes,
but it's going to take a little bit of
time and it's taking time because it's
actually writing one full gigabyte of
data
to this thumb drive. It does that
so as to overwrite anything that might
have been there before.
The difference then is very important
with a quick format.
The data that used to be there, it's
still kind of there,
and it's possible that data recovery
software
could recover some of the files that
were on that disk
after a quick format. A full format
methodically overwrites all of the data
on the drive
making it not impossible but
significantly more
difficult to recover the data on that
drive.
It's important to do a full format. Say
if there were sensitive data on that
drive,
even if you're not sure somebody might
recover the data
this is what you want to do before you
give a hard drive away. This is what you
want to do before you give a computer
away.
You want to carefully erase all of the
data on that drive and that means doing
a full format. As long as this is taking
it's the quickest way to ensure that
whatever you had
on that drive be it sensitive or not is
not going to be recovered by somebody in
the future.
So I'm going to go ahead and let this
finish.
And we're done. Like I said you can see
that that took a little bit longer
than the quick format. Exactly how long
will depend on exactly
how big your disk is and how fast it is
and how fast the interface is. For
example like I said this thumb drive is
a USB 2 thumb drive. I've got it plugged
into a USB 3 port but that didn't help
me at all.
So you get the idea. It depends on the
device how big it is and how fast it is.
How long a full format will take.
Now so far I've shown you two ways of
formatting a disk. I promised you four.
For the other two which are basically
just the same thing we've just done
in a different form. We're actually going
to fire up
Windows powershell. This all works in
command prompt as well.
Your choice. Powershell command prompt
admin or not.
The key of course is a command called
not surprisingly format.
Now I'm going to quickly do it with a
slash question mark because that will
show you what all of the options
are to this tool. I'm not going to go
through them all here. Obviously there's
a lot of them.
But you get the idea. There's a lot of
different options. A lot of different
things you can do,
a lot of different settings that may or
may not apply.
I'm going to format this hard drive
again
but I'm going to do it just using the
command line.
So if we say format format h
says insert the disk. It's actually still
optimized for floppy disks for removable
drives.
I've already got it attached. I'm going
to hit enter.
Doing a FAT file system and now the
default
turns out to be a full format
and by verifying 957 megabytes, well it's
actually writing 957 megabytes.
I'm going to let this complete and we
will come back
as soon as it's done.
Now in this case since there is no
field that I've specified, the volume
label beforehand or I didn't add it on
the command line
it's asking me for what I want that to
be, and then I'll once again type in
example.
And you can see then that we now have
this disk as example.
In fact, if I take a look at what's on h
it just says there's nothing there.
If I check disk. You can see that
volume
is named example when it was created
which is just now,
how big it is and so forth. But you get
the idea that it has been formatted.
Now interestingly enough as it was
chugging through
the format it dawned on me why a full
format is the default for the format
command.
If I go back to format h and add slash
q that's a quick format and it's done it
was literally that fast and I get to
enter my
volume title again.
The reason that it defaults to a full
format?
Floppy disks back in the day,
floppy disks had to be formatted before
they could be used.
And by formatted I mean literally the
surface had to be
formatted to be able to hold the data,
and that's a side effect. That's why the
name is
format, but it's why the default for the
command line version which goes
all the way back to ms-dos and before,
even why it defaults to being a full
format.
But there you go. Four different ways in
two different utilities,
how to format your hard disks and USB
thumb drives and whatever else appears
as a disk on your system.
Hope that was helpful hopefully maybe
even a little bit entertaining.
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I'm Leo Notenboom
and this
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