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A plus 220-1001 – Exam Objective 5.3 – Dumps4shared

A plus 220-1001 – Exam Objective 5.3

A+ Exam Objective 5.3 – ExamNotes

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5.3 Given a scenario, troubleshoot hard drives and RAID arrays.

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Welcome to ExamNotes by Dumps4shared! This
objective technically deals with hardware but as you’ll see, this objective has
a software thread running through it. Don’t ever think about these tests in a
strictly hardware or software sense. We need the software to direct the
hardware and the hardware to run the software. With that established let’s move
on. In this objective, we are asked to troubleshoot hard drives and RAID
configurations using the appropriate tools.

We will start out by examining the devices and configurations
you are likely to encounter. We will look at the drive, the configuration
possibilities, and the problems that may occur in the particular configuration.

Hard Disk
Drives (HDD)

This is by far the most recognizable component in modern
hardware. It has however undergone many changes. From the first hard drives to
today, the principle behind a hard drive is the same. A hard drive is a sealed
enclosure that contains several magnetic platters, the read/write heads, and
all the objects that makes operation possible. We’ll look at them closely
later.

Currently, a basic hard disk can come in two physical sizes:
2.5” and 3.5”. This doesn’t sound like a big difference but it is. The smaller
size accommodates the limited space requirements for a portable machine. In
addition, the smaller size reduces the energy requirement which saves valuable
battery life.

Let’s now look at the original, commercially available drive
which is the venerable 3.5” magnetic hard drive. This drive has been in use
since, believe it or not, when one could consider 5 MB a sufficient amount of
storage! During this time, a decent system would cost in the neighborhood of
$3,000 and you could get your own copy of the groundbreaking Windows 95! The
world has not been the same since!  Shown below is a great shot of the
inner workings of a HDD.

Hard Disk Drive (HDD) internal assembly

Inside the Hard Drive

Observe the perfection of the platters. This level of quality
and integrity is essential to ensure reliable performance and long Mean Time
Between Failure (MTBF). MTBF is a numeric representation of the average useful
life of a component, usually measured in tens of thousands of hours. If you are
responsible for the maintenance of hardware at your company, one of the many
essential tools is an external hard disk
enclosure
. This greatly simplifies the process of swapping drives in and
out of your machine for testing. Furthermore, it allows you to check the cables
and connectors involved in order to validate them.

Shown below is a 3.5” hard drive that is open and labeled. This image
explains in good detail the components inside the enclosure. We’ll start with
the platters.

Hard
Disk (HD) internal details labeled

Platters are very precisely machined and metallically coated. Platters
have been designed to store your data in incredibly small sections called
sectors. The data is read from and written to these sectors through the heads.
There is one head for each platter. The platters are double-sided and can hold
different data on either side. The tolerances in here are quite tight. For
example, a drive having three platters can easily hold 2 TB of data.

The heads are controlled by an actuator which consists of very strong rare earth magnets which control the actuator arms that hold the heads. The actuator can precisely move the heads to the right positions and can move them rapidly to the next location. Now this is where your speed is generated. By combining the rotational speed of the platters with the ability to read/write efficiently to either side of any platter, you have the speed and efficiency you need in a hard drive.

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Higher read/write metrics can be achieved by increasing the spindle
speed. Speeds are available from 5,400 RPM to 10,000 RPM and above. There are of
course advantages and disadvantages to everything. Let’s say you want to get
more speed from your laptop by switching to a 10,000 RPM from a 5,400 RPM hard
drive. Your laptop will be faster but your battery will run out twice as fast.

Common symptoms

By far the most common complaint about a working machine is slow
performance which many users tend to blame on the hard drive. Others blame the
processor or memory which is a little closer to home.

Slow
performance

Poor hard drive performance can be blamed on a number of
conditions. Fortunately, there are solutions for most of them. To address a
slow drive, you will want to use system tools to define and possibly repair the
problem. These tools include Defragmentation.

It is possible for a large file to exist with parts of the file spread
all over the disk. Parts of files that are not directly (logically) close to
each another are referred to as fragmented. Reading a file that is spread out
like this takes longer. The process of defragmentation
(Defrag) 
moves the associated files together in a contiguous arrangement
that is easier and faster for the drive to read. In addition, free space that
is clear is created to write data in. The end result is faster reads and
writes. This should be a once a month preventative maintenance activity.

Next, we’ll move to other drive problems that are associated by
their causes or repairs.

Here are some drive errors that can be pinpointed and possibly
remedied in the UEFI/BIOS.

Drive not
recognized

The drive was not auto-detected and the setup data needs to be
configured manually. Either that has occurred OR the drive has been damaged and
cannot be recognized by the system.

OS not
found 
and/or Failure to boot

The drive is improperly set up OR the drive is damaged beyond
repair. The operating system boot files are always located on the outermost
track of the hard drive. This space is reserved for this purpose alone.

RAID not found

This would indicate that the RAID controller has failed OR one
or more disks are misconfigured.

RAID stops
working

This would indicate that one or more of the RAID disks has
failed.

Reporting Technology (S.M.A.R.T) tests critical areas of hard
drive functionality quickly during boot to assess drive “health.” S.M.A.R.T.
errors appear when there is plenty of time to act, provided you act fast. This
is not the sort of error that will go away by itself.

Proprietary
crash screens (BSOD/pin wheel)

This screen is a death by degrees sort of thing. A BSOD (Blue
Screen of Death) is pretty much what the name implies. By the time you see a
BSOD, your system is already dumping the contents of its memory into a DMP file
to be used for diagnosis. The pinwheel indicates that the program you are
running has crashed and has taken some system functions with it. You may be
able to use Task Manager to recover.

Tools

Here is a look at some of the software tools that can be used to
fix any hard drive issues.

CHKDSK

This command, depending on the parameters used, can check a
drive’s overall condition all the way down to predicting sector failures and
getting the data off of them before there is a problem.

FORMAT

Use format when you are ready to start fresh. Formatting a
Windows disk essentially clears all data from the disk.

File recovery software

If you don’t have it turned on, turn it on now. Windows has the System
Restore feature that will restore your system back to a point before you had a
problem. Also, Windows SFC (System File Checker) will check critical Windows system
files and restore them if necessary.

Bootrec

This command can be used to repair the boot sector of a hard
drive including the files that belong there, such as the MBR and BCD.

Diskpart

This is a command line disk partitioning utility. It can be used
to delete all partitions on a disk or to re-arrange the sizes of partitions
provided there is space. Diskpart on a new drive can create a partition,
initialize it, and format it in preparation for the
operating system.

That’s all for 5.3! Good luck on the test.

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