Transcript Memory - Can You Compute?

Trends in
Memory
Computing
Changes in memory technology
• Once upon a time, computers could not store
very much data.
• The first electronic memory storage used
valves (like light bulbs that could be switched
on or off). One valve to store one bit.
Large number of valves in
the computer’s memory
Changes in memory technology
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Valves took up a lot of physical space.
They were very fragile.
They got hot very quickly.
If a valve overheated it would pop like a light
bulb. It could not be used to store data
anymore. The computer needed to be fixed!
• So computers that used valves for their
memory were not very reliable.
Changes in memory technology
• New electronic components
were invented that were smaller
and more reliable.
• Core memory was still physically
large and could not store very
much data by today’s standards.
Changes in memory technology
• Core memory used a grid of iron rings that could
be magnetised or de-magnetised.
• 1 ring is used per bit (binary digit).
• When you magnetise a ring it stores a 1, when it
is demagnetised it stores a 0.
• You still needed a lot of rings – 1 for every bit that
you store.
Changes in memory technology
• When transistors were invented, these small
electronic components were better for making
smaller memory circuits that actually had
more storage capacity.
• Smaller physical device, that can store more
data!
• Silicon chips were a further new development.
Thousands or millions of tiny transistors could
be stored on one small silicon circuit.
Changes in memory technology
• Modern memory circuits on chips are made
up of tiny logic gates.
• One of the gates that is used the most is the
NAND (Not-And) gate.
• The smaller the gates are, the more of them
can fit in a circuit or on a chip.
• As we have got better at making gates smaller
and smaller, the amount of memory that a
single chip can hold has got bigger and bigger.
Trends in memory
• Memory devices are getting physically
smaller as we get better at making them.
• At the same time, memory devices have a
larger capacity – they can actually store more
data.
• In 2000, a PC might have had 128 MB of RAM.
• Today, you can buy a typical PC might have
4GB of RAM.
Trends in memory
• USB Flash memory drives can store more and
more data – they have higher and higher storage
capacity.
• But they are getting physically smaller!
128 MB
128 MB
2003
2 GB
2 GB
4 GB
8 GB
2011
Trends in secondary storage
• A hard disk drive made in 1990 was physically
much bigger than a hard disk drive made in 2013.
Web link to the evolution of hard disk drives
Old hard disk
drive.
Physically big,
stores less
data.
Latest hard
disk drive.
Physically
smaller, stores
much more
data.
Trends in memory and storage
• The capacity of memory devices is getting
larger – they can store more data than they
used to.
• A hard disk drive in 1990 might have stored
only 250 megabytes.
• Today you can buy a hard drive that will store
2 terabytes (that’s about 8000 times more
storage space).
• Storage devices are also getting cheaper.
Trends in memory
• Storage devices are also getting cheaper.
• A device that stores the same amount of data
now costs much less than it did 10 years ago.
Quantum Memory
A traditional CPU uses the electronic states of, ‘no charge’ to represent a zero
and ‘charged’ to represent a one. Advancements in technology have enabled
scientist and engineers to create ‘Quantum computers’.
A quantum computer uses positively charged atoms to represent a one and
atoms with no charge to represent a zero. Millions of these states can be
written onto the size of a pinhead increasing the overall processing power of
the CPU.
The most significant benefit of a Quantum Computer is that these atoms can
be either state. They can represent simultaneously both a zero and a one.
While current computer perform one calculation at a time, a quantum
computer can perform several calculations all at once, in turn considerable
increasing the processing speed.
Biological Computing with DNA
Scientists have engineered human DNA to create a string of ‘0’ and
‘1’, a binary string of data.
Genetic elements and viruses are spliced into DNA, this creates a
reaction and this reaction can be interpreted as a either a one or a
zero. The process can be revised and overwritten several times
using the same strand of DNA. However, the DNA does break down
after a while and the data is lost.
Recently UK scientists have encoded an MP3 file, digital photos and
154 of Shakespeare's sonnets into DNA structure.