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Cost of DVD as data storage versus HDD (UK)



 
 
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  #132  
Old November 8th 04, 04:15 AM
Peter
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I wondered where he plucked that figure from, I might have
guessed if it was 60000, mind you I did say somewhere in this
thread, that on average the data you want to read will be at
the other side of the disk, so it is nice to see my 'observation'
is part of an industry standard :O)


Oh, it was he
http://www.pcguide.com/ref/hdd/perf/...Latency-c.html
http://en.tldp.org/HOWTO/Unix-Hardwa.../optimize.html


  #133  
Old November 8th 04, 10:56 PM
Simon Finnigan
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half_pint wrote:
.

Ok, so my drive spins at 7200 rpm, the same as yours. How big are
your platters? Lets be VERY generous, and say the full 5 gig
capacity of your drive is on a single platter. My smallest drive is
180 gigs - lets say there are 3 platters there. My platters
therefore hold 60 gigs each, despite being the same physical size as
your platters. Therefore the data density on my platters is 12
times greater than on yours.

Therefore, for each revolution of the platter, my drive can read 12
times more data. That`s 12 times the amount of data in the same
amount of time, making the data transfer rate 12 times greater.

Is that simple enough for you, or is it still too complicated for
you to understand?


You have demonstrated how stupid you are, you have no idea how a
computer works, statistacially the data will be on the other side of
the drive and it will take
your drive just as long to assess it as mine. (aprox bearing in mind
your marginally
faster spin speed).


As someone else has stated, on average the drive will have to seek across
half of the platter. Depending what you`re doing, this could be reduced a
lot (if you`re accessing a load of data in sequence on a fairly well
de-fragged drive), but I can`t see many real-world situations that would
increase that figure by any significant margin. Why do you think that the
only issue here is the access time? Incidentally, if my drive spins at
7200rpm, and you`re spins at 5400rpm, that`s not a marginal increase in spin
speed, it`s almost a 50% difference.

What is the access time on your drive, can you find out?

End of story.

Why can you not admit you are wrong?


Because I`m not wrong.

Out of interest, why do you spend so much of your life trolling? You REALLY
should try going out and getting laid sometime, I`m sure it`d help your
mental issues.

--
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Earn money reading emails!
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  #134  
Old November 9th 04, 12:06 AM
half_pint
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Posts: n/a
Default


"Simon Finnigan" wrote in message
...
half_pint wrote:
.

Ok, so my drive spins at 7200 rpm, the same as yours. How big are
your platters? Lets be VERY generous, and say the full 5 gig
capacity of your drive is on a single platter. My smallest drive is
180 gigs - lets say there are 3 platters there. My platters
therefore hold 60 gigs each, despite being the same physical size as
your platters. Therefore the data density on my platters is 12
times greater than on yours.

Therefore, for each revolution of the platter, my drive can read 12
times more data. That`s 12 times the amount of data in the same
amount of time, making the data transfer rate 12 times greater.

Is that simple enough for you, or is it still too complicated for
you to understand?


You have demonstrated how stupid you are, you have no idea how a
computer works, statistacially the data will be on the other side of
the drive and it will take
your drive just as long to assess it as mine. (aprox bearing in mind
your marginally
faster spin speed).


As someone else has stated, on average the drive will have to seek across
half of the platter. Depending what you`re doing, this could be reduced a
lot (if you`re accessing a load of data in sequence on a fairly well
de-fragged drive), but I can`t see many real-world situations that would
increase that figure by any significant margin. Why do you think that the
only issue here is the access time? Incidentally, if my drive spins at
7200rpm, and you`re spins at 5400rpm, that`s not a marginal increase in

spin
speed, it`s almost a 50% difference.

What is the access time on your drive, can you find out?

End of story.

Why can you not admit you are wrong?


Because I`m not wrong.

Out of interest, why do you spend so much of your life trolling? You

REALLY
should try going out and getting laid sometime, I`m sure it`d help your
mental issues.


Bit rich coming from you sunshine ;O)


  #135  
Old November 9th 04, 04:03 AM
Rob Morley
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Posts: n/a
Default

In article , "half_pint"
says...

"Rob Morley" wrote in message
t...
In article , "half_pint"

says...
"Rob Morley" wrote in message
t...

snip
Let's try this using really basic concepts and small words, shall we?

Imagine two hard drives - both single platter single-sided, same
rotational speed. One is 1GB, the other is 4GB. In order to get 4GB

in
the same space as 1GB, the larger drive has twice as many tracks, and
each track holds twice as much data as a track on the 1GB drive. Now
imagine that you want to read a file that occupies 3/4 track on the

4GB
drive - this will occupy 1 1/2 tracks on the 1GB drive, so while the

4GB
drive can read it in a single revolution, the 1GB drive will need to
make up to two revolutions to read the same amount of data. So, all
other things being equal (which they are not) the 4GB drive is up to
twice as fast as the 1GB drive.

Are you with me so far?


Yes!! Now imagine a file which occupies 1 degree of the track
(on *my* drive) and it is 180%s away (%=degree here)
the disk has to spin 181%s to get the data, however on your
'faster' drive it only has to spin 180.5 degrees, wow!!!!!
thats a great improvement!!!!! your drive is 181/180.5 faster
than mine, that is 1.00277 or 0.277% (back to real percents now).
So you are a quarter of a percent faster than me!!
Big deal!!!!!!! you would never notice it!!!!

Are you still with me?

Indeed. Now take into account that the head of the 1GB drive in my
example has to move from one track to the next before it can read the
second track - by the time it gets there it might have missed the start
of the data, in which case it would need another revolution before it
was read. This makes the 1GB drive a third of the speed of the 4GB
drive.
Now lets look at the combined effect of seek time and access time.
Assume an average seek time of 11 milliseconds for both disks.
For a 5400RPM drive one revolution takes 11 milliseconds. So for the
scenario in my example you have
for the 1GB disk: 11 + 11 + 11 + 11 = 44mS
for the 4GB disk: 11 + 11 = 22 mS
That's the worst-case scenario on an unfragmented disk. As you said,
the best-case scenario sees very little difference. So on average we
might expect the 4GB drive to have completed its read in 66% of the time
that it takes the 1GB drive. Remember we're talking a 4x difference in
arial density - the drives you were originally comparing were ISTR 5GB
per platter versus 60 GB per platter, which gives a difference in linear
density of around 330%, while my example used 200%.

Now tell me that the small drive is as fast as the big one - show your
workings.


I will do that tomorrow when I have more time :O)

Still waiting ...
  #136  
Old November 9th 04, 05:14 PM
half_pint
Guest
 
Posts: n/a
Default


"Rob Morley" wrote in message
t...
In article , "half_pint"
says...

"Rob Morley" wrote in message
t...
In article , "half_pint"

says...
"Rob Morley" wrote in message
t...
snip
Let's try this using really basic concepts and small words, shall

we?

Imagine two hard drives - both single platter single-sided, same
rotational speed. One is 1GB, the other is 4GB. In order to get

4GB
in
the same space as 1GB, the larger drive has twice as many tracks,

and
each track holds twice as much data as a track on the 1GB drive.

Now
imagine that you want to read a file that occupies 3/4 track on

the
4GB
drive - this will occupy 1 1/2 tracks on the 1GB drive, so while

the
4GB
drive can read it in a single revolution, the 1GB drive will need

to
make up to two revolutions to read the same amount of data. So,

all
other things being equal (which they are not) the 4GB drive is up

to
twice as fast as the 1GB drive.

Are you with me so far?


Yes!! Now imagine a file which occupies 1 degree of the track
(on *my* drive) and it is 180%s away (%=degree here)
the disk has to spin 181%s to get the data, however on your
'faster' drive it only has to spin 180.5 degrees, wow!!!!!
thats a great improvement!!!!! your drive is 181/180.5 faster
than mine, that is 1.00277 or 0.277% (back to real percents now).
So you are a quarter of a percent faster than me!!
Big deal!!!!!!! you would never notice it!!!!

Are you still with me?

Indeed. Now take into account that the head of the 1GB drive in my
example has to move from one track to the next before it can read the
second track - by the time it gets there it might have missed the

start
of the data, in which case it would need another revolution before it
was read. This makes the 1GB drive a third of the speed of the 4GB
drive.
Now lets look at the combined effect of seek time and access time.
Assume an average seek time of 11 milliseconds for both disks.
For a 5400RPM drive one revolution takes 11 milliseconds. So for the
scenario in my example you have
for the 1GB disk: 11 + 11 + 11 + 11 = 44mS
for the 4GB disk: 11 + 11 = 22 mS
That's the worst-case scenario on an unfragmented disk. As you said,
the best-case scenario sees very little difference. So on average we
might expect the 4GB drive to have completed its read in 66% of the

time
that it takes the 1GB drive. Remember we're talking a 4x difference

in
arial density - the drives you were originally comparing were ISTR 5GB
per platter versus 60 GB per platter, which gives a difference in

linear
density of around 330%, while my example used 200%.

Now tell me that the small drive is as fast as the big one - show your
workings.


I will do that tomorrow when I have more time :O)

Still waiting ...


It will be ready to read by Thursday.


  #137  
Old December 7th 04, 02:46 PM
J. Clarke
Guest
 
Posts: n/a
Default

half_pint wrote:


"guv" wrote in message
...
On Sat, 23 Oct 2004 03:59:36 +0100, "half_pint"
wrote:

Then you have to consider the huge ammount of grief you will get from
CD's (burning problems, scratched disks, disks which won't work,
CD writers which wont work .....well read this group and you will
get the general idea).

No one I know that looks after their media has any problems. Probably
best not to use them as beer mats.

Tell me about it!! They are a pretty fragile media as is a cd burner,
one scratch or a spec of dust and its all fooked.


Solution. look after them!

Then there is the time cnsumed bburning your CDs, how would you
cost that? Several hundred pounds?

How much would you consume fitting all these HDs you would need to
buy? Burning a 4.7GB disc is hardly an issue. Even at 2x its only 30
mins. Go get yourself a 16x burner if you are counting seconds.

Not good for audio, even converting mp3 to.wav takes an age (on my

ancient
machine)


Eh? Is it the fault of DVDR media, that it takes ages to convert wavs
to mp3? Might that be the same process time storing to your HD?


I can play from mp3 on my pc, I won't buy a cd player (.wav) ever again
only mp3 playing devices, so I will never need to convert.


Then there is huge problem of storing, locateing, indexing of the
CDs.......

Why is it a huge problem? The 200GB hard drive you mention, is only 40
discs. Go by yourself a 200 disc folder and have the equivalent of 5
of your 200GB hard drives.

I have about 80 cdr's finding a file on one of them could take *hours*.


So use some catalogue indexing software. Or is the issue you cant find
the discs because they are all over the place?



Whatever I have tried alll that, its too much hassel and it
doesn't get done when you are in rush and it is a job in it self.
How many hours (days more like) will it take to catalogue 300 DVD?

And then you cannot reorganise your files as you can on a HDD


Now start working out the costs.

200 discs will cost you 48, plus 50 for the burner.


How much will 5 200GB hard drives cost you? How much storage option do
you get once they are full?

Oh I see I am talking about CD's not DVD's but the argurements are
the same except DVD burners are very expensive.

Very expensive? Best not shop at PC world then. They are available for
just over 30.


All you get from burnable media is grief and coasters.

You 300DVDs are 3 meters high and hardly portable!!

Your 300 DVDs hold 1,200GB of data. How many hard drives are you
buying? How are you going to connect them all?

I think burning media is a dying art, in 3 years time
a 200GB drive will be what? 20?

Oh ok guys. Wait for 3 years and all will be well.

Well I ws mainly talking about CD's but DVD have the same problems.

I cannot use my computer whilst burning and thats a problem.


So because you have an "ancient PC" that wont use burn protection,
that writes of DVDR as a media does it? I always do other things at
the same time I am burning and have yet to have one buffer underrun
through doing so.



Ah so I heed to add the cost of a new PC into the equation now?
Well thats another 500 minimum, mind you as it will have a HDD
inside I won't need to burn!!


If yours is so old that is doesn't have underrun protection then maybe it's
time to upgrade on general principle.

My older cd drive dont work anymore either (occasionally works).
Its just too much hassle.


Sounds reasonable to suggest you get a new CD drive then. ;-)


Well I find HHD's infinitely more reliable so I will invest my money
in that direction, incidently that is not the original CD drive, the
original failed within the first year and I got a free replacent. So in
My experience they are not very reliable (also have a failed
portable CD radio thing).
And whilst it *may* be my fault they failed, none of my
HDD's have ever had a single problem!!!


So the drives break. So what? When they break they don't lose your data.

LIfe is too shor to burn media!!!


Since a 52X burner will take a few short minutes, how is that too
short?

How long will it take you to find a file on 300 DVD's?
A month?


Nope. Seconds. They are all in keep cases (apart from the 2nd back up)
and on a shelf and clearly marked.


Seconds? you have to read 300 lists, you must be a quick and flawless
reader, like my PC find files function.
It is a major hassle manintaining allyou lists and puting the corect
CD in the correct box.


Why would he have to read 300 lists? Just find the file that he wants in
the master directory, pull the numbered case he wants off the shelf, he's
done.

Or do you assume that the only record he has of what's on each CD is a paper
list? If so, you have no idea how to use the computer that is sitting in
front of you. Keeping that kind of information and making it accessible is
what computers _do_.

Oh and another advantage is the fact my Hard drive doesnt fit in my
set top DVD player! ;-)


Yes but you don't need a set top DVD player as you can play
direct from your PC.


But now you need two, one in your workroom and one in the living room next
to the TV. Or you have to lug it back and forth. And how do you get the
data from one to the other? Now you have a network to worry about. And
given that you are too cheap to get yourself a five year old computer for
20 bucks that has enough gumption to support underrun protection I doubt
that you're going to pay for a second computer just to play videos on the
TV.

Oh, you don't have two rooms of your own? That would explain much.

I have a big box full of floppies, another full of CD's
do i want another full of DVD'S?


But all your floppies and CDS will fit on a couple of DVDRs so it
sounds like another box isnt necessary in your situation.


Dont think I would trust a CD or a DVD, wont take up
much space on a HDD though.


Until that disk crashes and you lose _all_ of it, not just one DVD worth.

You do have your drives mirrored or RAIDEd I presume? No? Well, I predict
that in a few weeks or months or years you're going to be one of those
pitiful twits who comes on here with "I lost all my data, how can I get it
back without it costing me anything". To which the answer is "You're
screwed buddy".


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--
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Reply to jclarke at ae tee tee global dot net
(was jclarke at eye bee em dot net)
 




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