Math Forum Discussions

jdawe

Posts: 318
Registered: 11/8/09

Action-Reaction: Solid State Disk VS Hard Disk Drive
Posted: May 15, 2013 5:47 AM

Plain Text

SSD - HDD

A Solid State Drive (SSD) is probably better known as a Centre State
Drive, that is the data is all stored in the centre rather than the
perimeter like a Hard Disk Drive (HDD) does on curved disks that
rotate around the centre.

Centre - Perimeter

Linear - Curvature

Imagine taking a ballpoint pen and placing the point on the centre of
a spinning disc. Imagine this is the read head of a SSD. This head
doesn't have to move anywhere to access the data stored because all
the data is stored in the same spot ? directly in the centre. Because
the head doesn't have to move to access the data it is has
theoretically instantaneous access.

Static - Variable

Instantaneous - Gradual

The problem here is that only one unit of data can be stored in the
centre. So to increase capacity we have to place another disk over the
top of the first one. This will give us two units of storage space.

I suppose you could imagine a plate full of 10 pancakes stacked up
then taking a pen and driving it through the centre of the stack from
top to bottom. Each pancake layer has a centre with the pen going
through it. Each layer of pancake has one centre that can only store
one unit of data so in a stack of 10 pancakes you can store 10 units.

So, a SSD is going to store data in a vertical straight line from down
to up rather than a hard drive that stores data horizontal from right
to left along a curved disk.

Vertical - Horizontal

This is important to understand because a HDD storing data
horizontally from right to left is going to wear 'inward' so the more
times it is used the more it wears 'in' and the better performing it
will be. In direct opposition the SSD storing data vertically from
down to up is going to wear 'outward' so the more times it is used the
more it will wear out and the less performing it will be.

If we look back at the plate stacked up with pancakes and a single pen
driven vertically through the centre the pancakes represent 'quantity'
and that discrete quantity opposes the single pen continuum.

Singular - Plural

Continuum - Discrete

No matter how many pancakes we add to the plate there will only ever
be a single continuous tunnel down the middle.

Absolute - Relative

The pancakes revolve relative to the centre that is in a fixed state.

You don't need to worry about the pancakes touching each other because
when disks spin up they 'float' and are independent of the other
discs.

The disks horizontally levitate opposed to the centre tunnel which
represent vertical gravitation.

Vertical - Horizontal

Gravitation - Levitation

Linear - Curvature

--------------

This newsgroup post is an edited transcript of a number of posts I
made to an Internet forum where a question was raised regarding the
operation of an Solid State Drive.

http://forums.whirlpool.net.au/forum-replies.cfm?t=2097941#r13