What is a hard drive

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What is a hard drive?

• The hard drive stores all the computer's
  information and retains the information when the
  computer is turned off. A fast hard drive is
  needed to supply the CPU with data as fast as it
  needs it. Hard drive sizes are typically measured
  in GigaBytes. The larger the number, the more
  applications and games you can have installed. A
  hard drive can be IDE or SCSI. See IDE or SCSI
  for more information.

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What causes a hard drive to fail? Here are the
causes

•  Age - hard drives just grow old and die. It's
  inescapable. 
  
• Power failures and power spikes. Most of the
  time, your hard drive survives these with flying
  colors, other times?

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• Viruses can make your hard drive unreadable, or
  they can corrupt the data so it is unusable.
  Installing good virus protection is a must but
  isn't a guaranteed solution against viruses. 
• Physical damage. If you drop a hard drive (or the
  computer it is installed in) you can render the
  hard drive inoperable. Sometimes just sliding the
  system across the desk while the system is on can
  cause severe hard drive problems. 
• Defects in the hard drive - as with anything,
  hardware failures happen. 

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How to protect your data?

• Floppy Disk - Removable storage. This is not a
  suggested form of backup as floppy media is
  fairly unreliable. It would also be costly and
  time consuming, considering how much data is
  stored on today's hard drives. Floppy disks
  should be used for temporary storage, or to move
  something small from one machine to another. 
• Tape Drive - Removable storage. Tape drives can
  have very large capacities (and very large price
  tags). Tape drives are used mainly by businesses
  today. You can even buy tape drives that
  automatically feed many tapes so an unattended
  backup of an entire network in the middle of the
  night is possible.  

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• Using a second hard drive - Fixed storage. This
  is a viable backup method. It's quick, but it's
  still rather costly. This may become a more
  economical solution if used on a network where
  many people can save their important backup data
  to the same shared drive. 
• CD-R/CD-RW - Removable storage. This is probably
  the most cost effective method for backing up
  data . It's fairly fast (and getting faster all
  the time) and the blank media is very reasonable.
  You can store 650MB of data on a single CD-R or
  CD-RW disk, and the disk will be readable in
  pretty much any computer that has an optical
  drive. Newer PCs use DVDs for backup which can
  give even more space for storage

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• Online Storage. This is a very new industry that
  has emerged since broadband access to the
  Internet has become more widespread. This system
  allows you to copy your important data over an
  internet connection to a web server. You will
  need to pay for this service, generally on a
  monthly basis.

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What data to back up?

• The Favorites folder where you store your
  favorite Internet sites?
  
• Documents in your 'My Documents' folder?
• Pictures from your digital camera or received
  from family and friends?
  
• Email addresses of your friends and family?
• Old email?
• Characters from that game you've been playing for
  the last 3 months?
  
• Music files?
• Work from your business?

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How to replace your hard drive?

• Removing Hard Drive Mounting Screws Hard drives
  in PCs are either mounted in fixed cages (as
  above), in removable drive cages, or on rails.
  The standard method in older clones was fixed
  cages, these being the cheapest to build and the
  hardest to work with. The problem is that while
  the two screws on the front side are exposed and
  easily removed, as shown to the left, the two
  screws on the back side or hidden within the case
  infrastructure and in some instances, even
  blocked by the motherboard! The view in this case
  was so obscured there was no point trying to
  photograph it, but keep in mind that you have to
  remove four screws to replace your hard drive.

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• Once the screws are all removed, the hard drive
  is sitting in the bottom of the cage. This won't
  always be the situation, some really cheap cages
  are open at the bottom, so the instant the last
  screw is removed the drive drops if you aren't
  holding on. Oddly enough, this is the most
  critical stage of replacing a hard drive, in the
  sense that removing the drive through the case
  where the ribbon cables are bunched up and over
  the CPU and heatsink is most likely to create
  another problem. If the cables are long enough,
  you can leave them attached to the hardrive as
  you slide it out, but don't try pulling through a
  mess, clear a path first. Removing Hard Drive

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• Once the hard drive is out, you can remove the
  broad ribbon cable which carries the data and the
  4x1 power cable. The ribbon cable is sometimes
  secured in place with a glob of glue or silicon
  to prevent it from working out of the drive due
  to vibrations. The cable is often keyed properly
  to the drive, but if not, the important thing is
  to get the red wire on the Pin 1 location. The
  power connector is often tough to remove just
  because it's a tight fit. Work it back and forth
  gently along the long axis, making sure you
  aren't flexing the circuit board as you do so.
  The jumpers for Master/Slave are between the two
  cables.

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• Excuse the glare from the flash, but I wanted to
  point out the label on the replacement drive.
  When you replace or upgrade any hard drive, you
  want to make sure that the jumper settings for
  Master/Slave selection on older drives are set
  correctly. The correct setting, in case of a
  replacing a drive, means they should be set the
  same way they were on the old drive. In this
  case, the CD drive is installed on its own cable
  and controller, so the proper setting was
  "Single" (same as Master on most drives) and
  didn't need changing. These setting are normally
  shown on the label on the face of the drive, as
  to the right.

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• Again, since hard drive are three dimensional
  objects and fairly large relative to the size of
  the computer case, you have to clear plenty of
  room behind the cage to slide the drive straight
  in. Any time that you replace a hard drive and
  have new problems, like a CD that doesn't work or
  a new noise in the case, the culprit is usually a
  ribbon cable that's gotten loose on the
  controller while you were installing the hard
  drive, or a cable that's now hitting a
  fan.Install four screws (three is actually
  plenty) and the physical part of the job is over.

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What is memory?

• A computer is a machine that stores knowledge in
  its memory and does calculations on that
  knowledge. This knowledge is stored in symbols
  it is called data. A computer usually has a
  monitor to show results. However, some computers
  can speak these computers can be used for voice
  mail.
• Some computers are really simple calculators,
  like an abacus.

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What causes memory to freeze and crash?

• Application crashes are normally caused by one of
  two reasons either the user is asking the
  application to do something that it cannot do, or
  there is a glitch in the programming that
  causes the application to have a memory leak. If
  there is a glitch caused by the programmer, as
  the user works within the application it will
  begin using more and more of the computer's
  memory to do its job, sort of like starting with
  a full balloon of air and having the air slowly
  escape. Once all of the memory has escaped and
  there is none left, the application will crash,
  sometimes causing the entire computer to crash

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• Memory Violations
• A memory violation occurs when an application
  asks the operating system for more RAM, and the
  operating system doesn't have it, but the
  application pretends it received the higher
  allocation anyway. Let's say that you are using
  Photoshop to edit a large picture. Photoshop asks
  the OS for more RAM in order to make a huge
  gaussian blur. The OS says no go because there
  isn't any more RAM to give out. Photoshop ignores
  that fact, attempts to create the gaussian blur
  anyway, and creates a page fault, causing either
  Photoshop, or the entire computer to have to shut
  down.

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How to install new or more memory?
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Reasons for installing RAM?

• There are two good reasons for installing RAM in
  your system, either you want more total RAM
  installed, or your current module has failed.
  It's a simple job, providing you purchase a
  compatible memory module, almost all of which is
  in DIMM (Dual Inline Memory Module) form these
  days. The first task if to remove your old RAM
  and check the labeling, which is the surest way
  of making sure the replacement RAM will work.