building on your own a large data storage ...

Tim Southerwood · External Since: Apr 23, 2007 Posts: 113

bealoid coughed up some electrons that declared:

> This allows you to either buy many smaller drives (hitting the optimal
> dollar per gigabyte) or buy a few big fat drives and expand storage
> later.
>
> But, uh, I guess someone will be along to tell me that none of this
> will work with RAID. Sad

Au contraire: restriping to add an additional drive into RAID5 (and maybe
RAID6, I didn't pay attention) is in the newer 2.6 kernels. Not tried it
though. It will be slow (true of restriping on anything) and, although I
believe contingency measures are in the code, it's not the sort of
operation you really want your box to crash whilst it's in the middle of
it.

Another good option is to spec an 8 drive system, put 4 in now, 2-3 years
later, add a new 4 drives which are probably 2-3 times bigger by then for
the same money, and migrate the data over, remove the 1st 4 and use for
backups or something. That cycle can then be maintained for many years or
so, until the drives are no longer made with that interface or the system
is decrepid.

Tim

Ingo · External Since: Jun 08, 2007 Posts: 8

lbrtchx DeleteThis @hotmail.com schrieb:
> Hi,
> ~
> I need to store a really large number of texts and I (could) have a
> number of ATA100 S.M.A.R.T.-compliant hard drives, which I would like
> to use to somehow build a large and safe (RAID-5?) data store
> ~
> ~
> Should I got for ATA or SATA drives and why?
> ~
> You could use firewire and/or USB cards to plug in that many
> harddrives. Wouldn't it be faster/better using extra ATA PCI cards?
> What else would it entail? How many such cards could Linux take?
> ~
> People in the know use software based RAID. Could you give me links
> to these kinds of discussions?
> ~
> What would be my weak/hotspot points in my kind of design?
> ~
> Any suggestions of the type of boxes/racks I should use?
> ~

Have you ever thought of using some older x86 hardware/PC?
get all the obsolete pieces of hardware out and put the HD capacity yo
need in.

I have very good experience with 'FreeNAS', a FreeBSD based operating
system tailored for storage boxes. It is designed to hold the whole
operating system/firmware on a tiny CF-card, speaks NFS (essential for
Linux) and also FTP and CIFS. Administration is completely done via a
HTTP-web interface, including managing and adding new disks!

Check the homepage here:

http://www.freenas.org/

Best regards,
Ingo

Faeandar · External Since: Jul 06, 2007 Posts: 1

On Wed, 04 Jul 2007 04:12:06 -0700, lbrtchx RemoveThis @hotmail.com wrote:

> Hi,
>~
> I need to store a really large number of texts and I (could) have a
>number of ATA100 S.M.A.R.T.-compliant hard drives, which I would like
>to use to somehow build a large and safe (RAID-5?) data store
>~

How safe do you want it? RAID 5 is not the safest RAID, it's
basically better than nothing, but as RAID goes it's definitely entry
level.
Raid 1, Raid 1+0, Raid 5+1, Raid 6, etc. are all safer Raid levels.

> Now I am definitely more of a software person (at least
>occupationally) and this is what I have in mind:
>~
> * I will have to use standard (and commercially available (meaning
>cheap Wink

)) x86-based hardware and open source software
>~
> * AFAIK you could maximally use 4 hard drives in such boxes
>~

How big do you need this data store to be? Are we talking hundreds of
gig's or terabytes? If terabytes, 10's or 100's?

> * heat dissipation could become a problem with so many hard drives
>~
> * I need a reliable and stable power supply
>~
> Should I got for ATA or SATA drives and why?

There may be technical reasons to go with SATA over ATA besides
performance but personally I like the nicer cabling of SATA. If
you're looking to cram it all in one PC then that will be a factor.

>~
> You could use firewire and/or USB cards to plug in that many
>harddrives. Wouldn't it be faster/better using extra ATA PCI cards?
>What else would it entail? How many such cards could Linux take?
>~

Most cheap RAID controllers will handle up to 4 drives. You could
probably get two controllers and use a volume manager to pool the two.

> People in the know use software based RAID. Could you give me links
>to these kinds of discussions?
>~

What people are these? No one uses software raid except in rare or
specialized cases. NetApp uses software raid but they're highly
specialized. Most everyone else like BlueArc, EMC, HDS, Nexsan,
Overland, you name it all use hardware raid controllers. Recently Sun
came out with ZFS which is all software/file system raid but it's
pretty new and specific to the goals of the file system.
You can use software to pool multiple controllers together (as in a
volume manager) but using software to raid is just so 1986.

> What would be my weak/hotspot points in my kind of design?

You haven't given a design, just requirements.

>~
> Any suggestions of the type of boxes/racks I should use?
>~
> Is this more or less feasible? What am I missing here? Any other
>suggestions? or intelligent posts in which people have discussed these
>issues before? I found two in which some people have said a few right
>and some other questionable things:
>~
> comp.sys.ibm.pc.hardware.storage: "2 TB storage solution"
> comp.arch.storage: "Homebuilt server (NAS/SAN) vs the prefab ones?
>Peformance"
>~

For NAS, you could look at the previouslyt mentioned openfiler or go
to freenas.org.
freenas uses software raid, but it's exception is that it's free...

~F

Tim Southerwood · External Since: Apr 23, 2007 Posts: 113

lbrtchx.TakeThisOut@hotmail.com coughed up some electrons that declared:

>> You need to configure it right. Don;t use the full sector count of each
> disk, back off by about 0.5% - the 500GB disk you but next year to
> replace
> your 500GB from this year when it blows may be 100 sectors less - I've
> been
> caught out like that once.
> ~
> Aren't there any preferable regions in the disk? Should people leave
> them at the beginning, middle or end of it

No, just leave them at the end, which is the natural thing to do if
allocating from the start of the disk.

> ~
> I recall from when I used to see running scandisc that bad sectors
> tend to appear in clusters
> ~

The may tend too, but they could appear anywhere.

> Also I have heard people say that Western Digital drives tend to die
> slowly, while Maxtor ones die fast. To which extent are these
> differences between hard drives facts or myths?

Personally I wouldn't touch Maxtor with a bargepole, but they were bought
out by Seagate, who apparently are closing the Maxtor factories.

> Good readings on hard disk failures are:
> ~
> // __ http://labs.google.com/papers/disk_failures.pdf
> ~
> // __ http://www.cs.duke.edu/~justin/papers/tacs04going.pdf
> ~
> // __
>
http://en.wikipedia.org/wiki/Self-Monitoring,_Analysis,_and_Reporting_Technology
> ~ // __
>
http://www.usenix.org/events/fast07/tech/schroeder/schroeder_html/index.html
> ~ // __ http://arstechnica.com/news.ars/post/20070225-8917.html
> ~
> // __ http://www.gcn.com/print/26_10/44242-1.html
> ~
> Thanks
> lbrtchx

Walter Mautner · External Since: Oct 28, 2006 Posts: 55

Faeandar wrote:

......
>> People in the know use software based RAID. Could you give me links
>>to these kinds of discussions?
>>~
>
> What people are these? No one uses software raid except in rare or
> specialized cases. NetApp uses software raid but they're highly
> specialized. Most everyone else like BlueArc, EMC, HDS, Nexsan,
> Overland, you name it all use hardware raid controllers. Recently Sun
> came out with ZFS which is all software/file system raid but it's
> pretty new and specific to the goals of the file system.
> You can use software to pool multiple controllers together (as in a
> volume manager) but using software to raid is just so 1986.
>
We are talking about "consumer raid" here, with cheap chips and maybe
even "bios raid" which just disguises as a hardware raid, and most of the
time onboard controllers which die with the mobo.

Now, a hardware raid goes with it's controller - you can't put the drives in
elsewhere and expect the raid to be recognized again.

A software raid relies upon information stored on the drives so you can even
swap them between different linux versions/distributions, as long as the
controller and raid personality is supported by the kernel. Monitoring
(mdadm will send mail on drive failures if configured properly) a linux
software raid is a breeze as well, while you rely on special drivers for
hardware.

--
vista policy violation: Microsoft optical mouse found penguin patterns
on mousepad. Partition scan in progress to remove offending
incompatible products. Reactivate MS software.
Linux 2.6.17mm,Xorg7.2/nvidia [LinuxCounter#295241,ICQ#4918962]

Anton Ertl · External Since: May 21, 2006 Posts: 169

Faeandar <mr_castalot RemoveThis @yahoo.com> writes:
>On Wed, 04 Jul 2007 04:12:06 -0700, lbrtchx RemoveThis @hotmail.com wrote:
>
>> Hi,
>>~
>> I need to store a really large number of texts and I (could) have a
>>number of ATA100 S.M.A.R.T.-compliant hard drives, which I would like
>>to use to somehow build a large and safe (RAID-5?) data store
>>~
>
>How safe do you want it? RAID 5 is not the safest RAID, it's
>basically better than nothing, but as RAID goes it's definitely entry
>level.
>Raid 1, Raid 1+0, Raid 5+1, Raid 6, etc. are all safer Raid levels.

RAID 5 is good for surviving one disk failure, and RAID 1 with two
disks (the usual configuration) is also good for surviving one disk
failure.

>> People in the know use software based RAID. Could you give me links
>>to these kinds of discussions?
>>~
>
>What people are these? No one uses software raid except in rare or
>specialized cases.

We use software RAID, and that's all I recommend except in rare and
specialized cases. If you want to go with hardware or fake RAID, buy
at least two controllers (or motherboards if you are using an on-board
controller), so that you can still access the volumes when a
controller dies.

- anton
--
M. Anton Ertl Some things have to be seen to be believed
anton RemoveThis @mips.complang.tuwien.ac.at Most things have to be believed to be seen
http://www.complang.tuwien.ac.at/anton/home.html

Ogre · External Since: Jun 04, 2007 Posts: 20

lbrtchx DeleteThis @hotmail.com wrote:
> Hi,
> ~
> I need to store a really large number of texts and I (could) have a
> number of ATA100 S.M.A.R.T.-compliant hard drives, which I would like
> to use to somehow build a large and safe (RAID-5?) data store

You don't say how large it needs to be. Raid 5 gives you
(drives-1)*size in space. So with four drives of 500Gigs each you get
1.5T (ignoring the difference between manufacturer size and real world
size). Need more space, go with 750Gig drives. The 1T disks are
probably too pricey to consider.

> * I will have to use standard (and commercially available (meaning
> cheap Wink

)) x86-based hardware and open source software
> ~
> * heat dissipation could become a problem with so many hard drives
> ~

My motherboard supports 12 SATA drives. I'd probably need a few extra
fans and a bigger power supply, though. If you need more than four
drives then you are probably beyond the realm of "cheap", but you don't
necessarily have to go to "bloody expensive".

> ~
> What would be my weak/hotspot points in my kind of design?

You've covered it. Heat is going to be a big factor so you'll need a
case with lots of cooling capability.

A quality power supply will be essential.

With that many drives in the box, drive failure becomes an even bigger
factor. I'd probably go with two sets of RAID 5 or a RAID 5/1
combination (if I'm really paranoid), but the latter is a bit costly as
you use twice as many disks; space = (drives-1)*size/2.

Consider off-the-shelf solutions, too. There are some decent home
network quality filers out there. I wouldn't use them in a critical
business job, but something like that might be good enough for your needs.

--
Ogre

Bill Todd · External Since: May 11, 2005 Posts: 8

lbrtchx DeleteThis @hotmail.com wrote:

....

> * they do mention (I found it somewhat silly) the importance of
> taking into account the app usage patterns and other OS
> characteristics (including the FS used)

Why do you find that silly? Most (S)ATA drives are specced for a
relatively low duty cycle (8 hours per day), while enterprise drives are
specced for 24/7 operation: this doesn't make much difference in light
use (or for streaming sequential access), but it could easily make a
significant difference in longevity if (S)ATA drives were used in
seek-intensive (e.g., heavy OLTP) applications 24/7 (and exactly how the
file system organizes and accesses its data can also contribute to
higher or lower seek loads).

> ~
> To me these pieces of information are crucial. If you don't know the
> manufacturer's + model (+ even vintage/production cycles) you can't
> tell how much of the drive internal cache was being used.

That's probably almost completely irrelevant (at most, in a
write-intensive environment with disk-level write-back caching turned on
and lots of nominally synchronous small-write activity from the host
that it could not handle in its own write-back cache it might matter some).

....

> Something I notice is that some hard drives are placed vertically in
> some computers and horizontally in some others, but I think (actually
> it could be even proved) drives (their electro-mechanical parts) are a
> lot less taxed if they spin vertically, but I don't hear of anyone
> talking about these kinds of things ...

That's probably because they really don't matter.

> ~
> I am talking about the torque needed to reach a rotational momentum
> to actually rotate the drive.
> ~
> http://en.wikipedia.org/wiki/Torque
> ~
> I would even say that there is a linear relationship (depending on
> the lever) between the torque needed to move a flat cylinder (a
> platter) horizontally and to move it vertically. I am a freaking
> physicist, if you couldn't tell Wink

Your misconceptions in the preceding paragraph are not those I'd expect
from an actual physicist: are you sure you're not just a student?

> ~
> I wonder how is it manufacterers would say it does not matter. I mean
> I would even consider earth magnetism to place the drives in certain
> ways

Pure poppycock.

- bill

lbrtchx · External Since: Jun 24, 2007 Posts: 15

> > Well, I don't think that having a discussion about something we don't
> > really know (what is actually happening in googles servers'
> > infrastructure) is worthy,
~
> Speak for yourself: I suspect that I have a fairly good idea of what's
> happening there.
~
> > and no, I am not a student.
~
> You're certainly not much of a physicist
~
"not much"? ... OK, Mr. "I-know-what-happens-inside-google-servers"
define muchNESS for me. You may be right. Ja, ja, ... Also I am
talking here in this public newsgroup more in a general than
personally to you
~
I wonder what makes you be so certain about me not being a physicist,
but hey even though google salary might be definitely enough for you
to lose a bet on it, I would rather ask you to convince your sugar
momm[y|ies] (or extensively so) to come clear with "their findings".
Not every body out there is so technically cynical
~
http://www.usenix.org/events/fast07/tech/schroeder/schroeder_html/index.html
~
Unfortunately, many aspects of disk failures in real systems are not
well understood, probably because the owners of such systems are
reluctant to release failure data or do not gather such data. As a
result, practitioners usually rely on vendor specified parameters,
such as mean-time-to-failure (MTTF), to model failure processes,
although many are skeptical of the accuracy of those models [4,5,33].
Too much academic and corporate research is based on anecdotes and
back of the envelope calculations, rather than empirical data [28].
~
4
J. G. Elerath.
AFR: problems of definition, calculation and measurement in a
commercial environment.
In Proc. of the Annual Reliability and Maintainability Symposium,
2000.

5
J. G. Elerath.
Specifying reliability in the disk drive industry: No more MTBFs.
In Proc. of the Annual Reliability and Maintainability Symposium,
2000.

33
Jimmy Yang and Feng-Bin Sun.
A comprehensive review of hard-disk drive reliability.
In Proc. of the Annual Reliability and Maintainability Symposium,
1999.

28
T. Schwarz, M. Baker, S. Bassi, B. Baumgart, W. Flagg, C. van
Ingen, K. Joste, M. Manasse, and M. Shah.
Disk failure investigations at the internet archive.
In Work-in-Progess session, NASA/IEEE Conference on Mass Storage
Systems and Technologies (MSST2006), 2006.
~
lbrtchx

Ingo · External Since: Jun 08, 2007 Posts: 8

>> * I will have to use standard (and commercially available (meaning
>> cheap Wink

)) x86-based hardware and open source software
>> ~
>> * heat dissipation could become a problem with so many hard drives
>> ~
>
> My motherboard supports 12 SATA drives. I'd probably need a few extra
> fans and a bigger power supply, though. If you need more than four
> drives then you are probably beyond the realm of "cheap", but you don't
> necessarily have to go to "bloody expensive".
>
>> ~
>> What would be my weak/hotspot points in my kind of design?
>
>

I think that the discussion here is only half of the story:

it is not too difficult to build a > 1TB storage system/NAS. The more
disks are used to make up the capacity the higher the risk of failure!

So whatever RAID solution is used, it does not substitute a regular and
reliable backup! And with these capacities the backup-system (tape) will
be more expensive than the whole box!

Regards,
Ingo

Bill Todd · External Since: May 11, 2005 Posts: 8

lbrtchx DeleteThis @hotmail.com wrote:

....

>>> and no, I am not a student.
> ~
>> You're certainly not much of a physicist
> ~
> "not much"? ... OK, Mr. "I-know-what-happens-inside-google-servers"
> define muchNESS for me. You may be right.

Unless you can come up with convincing support for your drivel about
varying amounts of energy required to spin a cylinder depending upon the
static orientation of its axis of rotation with respect to the gravity
field, I suspect most people with any understanding whatsoever of the
subject will conclude that I *am* right.

Ja, ja, ... Also I am
> talking here in this public newsgroup more in a general than
> personally to you
> ~
> I wonder what makes you be so certain about me not being a physicist,

I think I answered that above (if my earlier comment was not
sufficiently specific for you to understand).

> but hey even though google salary might be definitely enough for you
> to lose a bet on it, I would rather ask you to convince your sugar
> momm[y|ies] (or extensively so) to come clear with "their findings".
> Not every body out there is so technically cynical

I'm really not all that cynical - just competent (at least in the
subjects upon which I choose to venture a strong opinion).

> ~
> http://www.usenix.org/events/fast07/tech/schroeder/schroeder_html/index.html

Thanks - read it months ago (and understood it, apparently unlike yourself).

- bill

Kevin Snodgrass · External Since: Oct 20, 2006 Posts: 43

Bill Todd wrote:
> Unless you can come up with convincing support for your drivel about
> varying amounts of energy required to spin a cylinder depending upon the
> static orientation of its axis of rotation with respect to the gravity
> field, I suspect most people with any understanding whatsoever of the
> subject will conclude that I *am* right.

Don't chase this one away. I'm really interested in the new torque
definition and formula.

lbrtchx · External Since: Jun 24, 2007 Posts: 15

> Oh, I did just peruse 2 of my college texts (University Physics, 6th Ed. Sears, Zemansky, Young; Mechanics 3rd Ed, Symon) and they both give tourque as I remembered it; the cross product of the Force vector with the Radial vector. No mention of the gravity vector.
~
Many school physics books and some of those "for engineers" are very
simple and basic even about relatively over-simplistic (and
simplified) Mechanics
~
I think what your books missed was that the angular momentum of a
solid body you calculate over an integration and in this integration
are considered
~
* gravity
* mass density distribution (pretty much constant for a hdd's
platter)
* lever
* objects volumetric form as "perceived" by the rotating axis
~
Do a search on "gravitational torque". Some of these links may lead
you there
~
// __ http://en.wikipedia.org/wiki/Torque
~
// __ http://en.wikipedia.org/wiki/Angular_momentum
~
// __ http://en.wikipedia.org/wiki/Center_of_mass
~
// __ http://physnet.org/home/modules/pdf_modules/m34.pdf
~
// __ http://www.lightandmatter.com/html_books/2cl/ch05/ch05.html
~
// __ http://physics.ucsd.edu/students/courses/fall2005/physics2aa/Solutions..._Sugges
~
> > gaging/measuring the amount of power a drive consumes in both
> > positions will ultimately say the truth
>
> Got a Kill-O-Watt and a couple volt meters. Maybe I'll try that.
~
I would bet half of my right gut Wink

that you need to do more work,
therefore there will ultimately be more power consumption, but both
spindle the hard drive's platter and its reading magnetic arm while
having the drive horizontally placed. How much more I don't know
~
lbrtchx

Kevin Snodgrass · External Since: Oct 20, 2006 Posts: 43

lbrtchx RemoveThis @hotmail.com wrote:
>>Oh, I did just peruse 2 of my college texts (University Physics, 6th Ed. Sears, Zemansky, Young; Mechanics 3rd Ed, Symon) and they both give tourque as I remembered it; the cross product of the Force vector with the Radial vector. No mention of the gravity vector.
>
> ~
> Many school physics books and some of those "for engineers" are very
> simple and basic even about relatively over-simplistic (and
> simplified) Mechanics

Ah, so my University Physics books are Physics for Dummys. I see. Did
I mention Mechanics, by Symon, is a grad school book?

> I think what your books missed was that the angular momentum of a
> solid body you calculate over an integration and in this integration
> are considered

When you are dealing with a non-rigid body, you have a point. The
platter(s) of a hard drive are quite rigid, therefore you do not have a
point when dealing with hard drives.

> * gravity

Please, do explain. I'm still waiting for your explainantion of how
gravity can affect energy requirements for spinning a small aluminum
disk, inre disk parallel to gravity vector vs. disk perpendicular to
gravity vector.

> * mass density distribution (pretty much constant for a hdd's
> platter)

Damn well better be. At spin rates of 5400, 7200, 10K and 15K rpm any
non-constant mass distribution will cause serious issues.

> * lever

Constant in this case.

> * objects volumetric form as "perceived" by the rotating axis

Constant in this case.

> Do a search on "gravitational torque". Some of these links may lead
> you there

I already did. Nothing new here...

>>>gaging/measuring the amount of power a drive consumes in both
>>
>> > positions will ultimately say the truth
>>
>>Got a Kill-O-Watt and a couple volt meters. Maybe I'll try that.
>
> ~
> I would bet half of my right gut Wink

that you need to do more work,

The phrase is "bet my right nut", as in gonad. I would suggest betting
something less important, like maybe a box of Krispy Kremes.

> therefore there will ultimately be more power consumption, but both
> spindle the hard drive's platter and its reading magnetic arm while
> having the drive horizontally placed. How much more I don't know

Probably non-existant, but most certainly smaller than a Kill-o-Watt
(digital), cheap digital multi-meter (digital), or the Voltmeter on my
engine analyzer (analogue) can resolve.

lbrtchx · External Since: Jun 24, 2007 Posts: 15

> ~
> > Many school physics books and some of those "for engineers" are very
> > simple and basic even about relatively over-simplistic (and
> > simplified) Mechanics
~
> Ah, so my University Physics books are Physics for Dummys. I see. Did I mention Mechanics, by Symon, is a grad school book?
~
I don't know about this particular book, but you could see what I
meant. Even the wikipedia entry for the explanation of what "torque"
is was so basic that it read like an odd joke to me
~
> > I think what your books missed was that the angular momentum of a
> > solid body you calculate over an integration and in this integration
> > are considered
~
> When you are dealing with a non-rigid body, you have a point. The
> platter(s) of a hard drive are quite rigid, therefore you do not have a
> point when dealing with hard drives.
~
Actually no. There is a form factor that factors (no pun intended)
into the integral to calculate the angular momentum
~
> > * gravity
> > * lever
> > * objects volumetric form as "perceived" by the rotating axis
~
> Please, do explain. I'm still waiting for your explainantion of how
> gravity can affect energy requirements for spinning a small aluminum
> disk, inre disk parallel to gravity vector vs. disk perpendicular to
> gravity vector.
~
I still owe you those one
~
> > Got a Kill-O-Watt and a couple volt meters. Maybe I'll try that.
~
> I would bet half of my right gut Wink

that you need to do more work,
~
> The phrase is "bet my right nut", as in gonad. I would suggest betting
> something less important, like maybe a box of Krispy Kremes.
~
Wink

~
> > therefore there will ultimately be more power consumption, but both
> > spindle the hard drive's platter and its reading magnetic arm while
> > having the drive horizontally placed. How much more I don't know
~
> Probably non-existant, but most certainly smaller than a Kill-o-Watt
> (digital), cheap digital multi-meter (digital), or the Voltmeter on my
> engine analyzer (analogue) can resolve.
~
Hmm! That was interesting to me! How did you make the drive spin?
Issuing internal assembler code to just make it spin without any rw
work and keeping its arm parked?
~
lbrtchx

lbrtchx · External Since: Jun 24, 2007 Posts: 15

> ~
> > Many school physics books and some of those "for engineers" are very
> > simple and basic even about relatively over-simplistic (and
> > simplified) Mechanics
~
> Ah, so my University Physics books are Physics for Dummys. I see. Did I mention Mechanics, by Symon, is a grad school book?
~
I don't know about this particular book, but you could see what I
meant. Even the wikipedia entry for the explanation of what "torque"
is was so basic that it read like an odd joke to me
~
> > I think what your books missed was that the angular momentum of a
> > solid body you calculate over an integration and in this integration
> > are considered
~
> When you are dealing with a non-rigid body, you have a point. The
> platter(s) of a hard drive are quite rigid, therefore you do not have a
> point when dealing with hard drives.
~
Actually no. There is a form factor that factors (no pun intended)
into the integral to calculate the angular momentum
~
> > * gravity
> > * lever
> > * objects volumetric form as "perceived" by the rotating axis
~
> Please, do explain. I'm still waiting for your explainantion of how
> gravity can affect energy requirements for spinning a small aluminum
> disk, inre disk parallel to gravity vector vs. disk perpendicular to
> gravity vector.
~
I still owe you those one
~
> > Got a Kill-O-Watt and a couple volt meters. Maybe I'll try that.
~
> I would bet half of my right gut Wink

that you need to do more work,
~
> The phrase is "bet my right nut", as in gonad. I would suggest betting
> something less important, like maybe a box of Krispy Kremes.
~
Wink

~
> > therefore there will ultimately be more power consumption, but both
> > spindle the hard drive's platter and its reading magnetic arm while
> > having the drive horizontally placed. How much more I don't know
~
> Probably non-existant, but most certainly smaller than a Kill-o-Watt
> (digital), cheap digital multi-meter (digital), or the Voltmeter on my
> engine analyzer (analogue) can resolve.
~
Hmm! That was interesting to me! How did you make the drive spin?
Issuing internal assembler code to just make it spin without any rw
work and keeping its arm parked? Could you do us the favor to let us
know about the specifics of how exactly did you do it?
~
If there is anything you could safely believe in is Physics
~
lbrtchx

lbrtchx · External Since: Jun 24, 2007 Posts: 15

> > Many school physics books and some of those "for engineers" are very
> > simple and basic even about relatively over-simplistic (and
> > simplified) Mechanics
~
> Ah, so my University Physics books are Physics for Dummys. I see. Did I mention Mechanics, by Symon, is a grad school book?
~
I don't know about this particular book, but you could see what I
meant. Even the wikipedia entry for the explanation of what "torque"
is was so basic that it read like an odd joke to me
~
> > I think what your books missed was that the angular momentum of a
> > solid body you calculate over an integration and in this integration
> > are considered
~
> When you are dealing with a non-rigid body, you have a point. The
> platter(s) of a hard drive are quite rigid, therefore you do not have a
> point when dealing with hard drives.
~
Actually no. There is a form factor that factors (no pun intended)
into the integral to calculate the angular momentum
~
> > * gravity
> > * lever
> > * objects volumetric form as "perceived" by the rotating axis
~
> Please, do explain. I'm still waiting for your explainantion of how
> gravity can affect energy requirements for spinning a small aluminum
> disk, inre disk parallel to gravity vector vs. disk perpendicular to
> gravity vector.
~
I still owe you those ones
~
> > Got a Kill-O-Watt and a couple volt meters. Maybe I'll try that.
~
> I would bet half of my right gut Wink

that you need to do more work,
~
> The phrase is "bet my right nut", as in gonad. I would suggest betting
> something less important, like maybe a box of Krispy Kremes.
~
Wink

~
> > therefore there will ultimately be more power consumption, but both
> > spindle the hard drive's platter and its reading magnetic arm while
> > having the drive horizontally placed. How much more I don't know
~
> Probably non-existant, but most certainly smaller than a Kill-o-Watt
> (digital), cheap digital multi-meter (digital), or the Voltmeter on my
> engine analyzer (analogue) can resolve.
~
Hmm! You see now we are talking! That is interesting to me! How did
you make the drive spin? Issuing internal assembler code to just make
it spin without any rw work and keeping its arm parked?
~
lbrtchx

lbrtchx · External Since: Jun 24, 2007 Posts: 15

> cosmic rays ...
~
in his excellent book about soft not hardware:
~
Why Programs Fail: A Guide to Systematic Debugging; ISBN-10:
1558608664
~
Andreas Zeller states cosmic rays don't affect computers ...
~
I had read otherwise @@
~
lbrtchx