>> Hi, everybody. Welcome back to the course.
In the last video, we talked about
the different types of file systems.
We talked about FAT,
NTFS, and then also the Linux file systems.
Extended file systems, so ext,
ext2, ext3, and ext4.
In this video, we're going talk about HFS
and HFS Plus for Mac,
but be very briefly.
Then we'll also take a high-level overview
of the different raid levels.
Again, the raid levels are definitely
something you'll want to know for the examination.
HFS and HFS Plus,
that's a hierarchical file system.
The difference there, HFS uses 16-bit allocation blocks.
HFS Plus uses a B-tree structure.
Specifically for your exam,
remember that HFS Plus uses a B-tree structure.
Just in case it's tested on there,
that was one of the more popular angles
inside of the official [inaudible] counting material.
Generally when they mentioned stuff multiple times,
you usually see it on their examinations.
RAID. We'll talk about
what it means here in just a second.
But we have different levels here as shown.
We will talk about each one and what that means.
RAID stands for redundant array,
and it used to be of inexpensive disks.
You might see it nowadays listed
as Redundant Array of Independent Disks.
It just depends on what you're
looking at for a source and what is called.
At the end of the day, it's still R-A-I-D,
still smells RAID, so that's what we go.
RAID 0. Some of the things with that one,
it offers disk striping, but no redundancy.
If one of them fails, we're done.
Then it requires two drives minimum.
RAID 1, it offered mirroring.
The cool thing there, offers redundancy.
If one of my disk fails,
I've still got an exact copy
on the other disk of my data,
and so I can just keep going.
Now, this one also has requirements
or requires two drives minimum.
We've also got RAID 2.
This one here doesn't use
any parity, mirroring, or striping.
That's a little different than the other RAID levels.
This one splits data at the bit level and
then distributes that data to multiple disk.
We have RAID 3,
this one here uses byte level striping,
then also a dedicated period disk.
This one also stores checksums.
This one is unable to cater to
multiple data requests at the same time.
That's one thing you'll definitely
want to remember as well.
We have RAID 5, which is
uses a byte level data striping.
It also requires three drives minimum.
Again, as there is a minimum
requirements here for the RAID,
just make sure you memorize,
like for example, RAID 5 has three drives minimum.
This RAID level has this,
this one has this, etc.
Then we have RAID 10 or RAID 1 plus 0.
This one actually combines,
as the name implies, RAID 0 and RAID 1.
So it combines the striping in the mirroring.
It requires four drives minimum.
That's one aspect of it is a little more expensive than
other options and then
the fault tolerance is actually similar to RAID 1.
Then if two disks in the same mirrored pair fail,
then the data is not going to be available.
That's some common sense there,
but it just in case you didn't know that.
Just one quick post assessment question here.
This type of RAID combines mirroring and striping.
If you answered RAID 10 or if you
screamed out at the computer,
hey, it's RAID 1 plus 0,
both of them we use interchangeably.
RAID 10 in that list is the correct answer there.
In this video, we talked about
the different raid levels as well as just a brief
overview of HFS and HFS Plus.
In the next video, we're going to talk about
things like file carving,
how to analyze different image files,
and then also the solution kit.