Information Technology Reference
In-Depth Information
ever.really.said.such.a.thing.is.unlikely,.but.it.is.worth.recog-
nizing. that. way. back. when,. this. much. storage. seemed. like.
quite.a.bit..At.one.time,.640,000.(or.so).pieces.of.information.
probably.seemed.like.plenty.
But,. it. wasn't. long. before. we. started. talking. in. terms. of.
megabytes.or.one.million.bytes.(actually.2
20
.as.noted.above)..
That.might.seem.like.it.would.be.a.lot,.but.these.days.if.you.
told. someone. you. had. a. hard. drive. with. one. megabyte. of.
storage,.they.would.laugh.in.disbelief.that.such.a.tiny.amount.
of.storage.could.even.exist..It.is.impossible.to.ind.a.hard.drive.
with.any.amount.of.megabytes.of.storage.these.days.because.
we.kept.running.out.of.room.and.we.had.to.move.up.again.
The.next.step.is.gigabytes—.or.one.billion.(plus).bytes..All.
modern.hard.drives.are.listed.with.capacities.of.gigabytes..In.
fact,.at.the.time.of.this.writing.it.is.nearly.impossible.to.ind.a.
hard.drive.with.less.than.80.gigabytes.of.storage..Drives.with.
500. gigabytes. are. available. for. under. $100. and. in. fact. my.
favorite.computer.store.recently.had.a.sale.on.one.terabyte.
(one. trillion. [plus]. bytes). drives. for. less. than. $50. and. three.
terabyte.drives.for.less.than.$130.
Now,.I.have.to.admit.that.I.hesitated.to.emphasize.those.
numbers. above. because. of. something. called. Moore's. Law.
that. predicted. that. the. number. of. transistors. that. could. be.
placed.in.a.computer.(thus.the.size.and.capacity.of.the.com-
puter. system). would. double. every. 2. years.. This. has. in. fact.
proven.to.be.true.and.is.expected.to.continue.for.some.years.
to.come..Thus.the.numbers.that.seem.pretty.amazing.right.
now.will.no.doubt.be.blasé.to.folks.who.might.be.reading.this.
topic.in.years.or.even.months.to.come.
But.that's.as.it.should.be..Understand.that.way.back.in.the.
dark.ages.of.2011,.a.terabyte.hard.drive.for.under.$50.was.a.
pretty.exciting.thing.to.a.geek.
One.inal.idea.we.need.to.understand.before.moving.on—
and. that. is. the. difference. between. volatile. and. nonvolatile.
types.of.data.storage..All.these.bytes.of.information.are.stored.
in. your. computing. devices. in. one. of. two. ways. (and. often.
both)..As.you.are.working.on.a.document.or.in.an.application.
