Author Topic: EEVblog #395 - World's Most Expensive Hard Drive Teardown  (Read 29113 times)

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Offline calin

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Re: EEVblog #395 - World's Most Expensive Hard Drive Teardown
« Reply #15 on: December 06, 2012, 04:30:01 AM »
Indeed .. great. Used to have a similar at the university - came in really handy when we learned peripherals and storage. Not as sexy as this one but good learning tool.

BTW, u know IBM still calls the mainframe storage DASD up to these days.  I have a guy around me that is old enough to have seen these in use - he was overjoyed when I showed him the video :) .


Offline SeanB

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Re: EEVblog #395 - World's Most Expensive Hard Drive Teardown
« Reply #16 on: December 06, 2012, 05:07:50 AM »
BTW, the removal of the heads off the media is called parking........

Those disks are not sputtered units, they are spin coated. Pour a small slurry of ferrite and binder onto the inside while it spins at high speed and it will be evenly distributed over the disk, like in modern CD production when they are coating the optical pit layer with the top coating. No fancy magnetics at that low density, just finely ground iron oxide and chromium oxides that are sieved then blended in a ball mill to a fine submicron powder then mixed with a solvent based carrier to stick it to the aluminium platters. During final test there would have been a special jig that moved the head assemblies a precise amount as it wrote servo tracks on the one platter.

As to the magnetics, the writing direction is in x, the material in the gap forces the magnetic field to spread out into the magnetic media in the Y direction ( and a little internally as well) while the Z is inter track coupling. the data is written by the magnetic field at the trailing edge of the head gap ( it retains the magnetic orientation it has as it left the field in the gap) while the reading is of the material in the whole gap. That is why on later units you will have had 2 coils in a line, the first with a very small gap does the reading off the disk, while the back one a certain precisely controlled  time behind ( actually distance travelled as radial velocity of the disk) can write the new data onto the sector block after the read head has read the preamble and been servoed into alignment on the track. this compensates for offset due to heating and expansion of the platters and heads, yours has a servo platter that does the same function.

Older ones had a big enough head ( same as a floppy drive size wise) that they could ignore it mostly, as the tracks were set by a stepper motor.

As to the air lines, those are not Halon, but for pressurised clean dry air from a built in compressor and filter drier pack in the drive bay, used to circulate clean air into the drive case and remove the hot interior air. The cool air is aimed via the microfilters inside to pass over the heads, then pass through another filter before circulating through the disk pack and then exiting via the spindle motor to cool it. Thus the holes in the spacers so air can go down. All designed so there is no turbulent flow on the disk pack where the heads are flying just above the disk, on a thin cushion of air compressed by the wedge shape on the bottom. This keeps the heads almost in contact with the platter so the magnetic field does not spread out and weaken, but reduces the friction to almost zero, and reduces wear to almost nothing. Compared size wise to flying a 747 at full speed 6 inches over the ground.

Offline kyndal

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Re: EEVblog #395 - World's Most Expensive Hard Drive Teardown
« Reply #17 on: December 06, 2012, 05:45:42 AM »
as for taking the linear actuator apart.
looks to me like there is a "hinge like" mechanism on each side with a pin going length wise
down / through the side ?

what do you mean you dont have pneumatic impact tools in your shop ??

;)

Offline SeanB

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Re: EEVblog #395 - World's Most Expensive Hard Drive Teardown
« Reply #18 on: December 06, 2012, 05:51:39 AM »
The magnet holds it together, you need a set of jigs that pry the poles apart to get it open.

Online free_electron

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Re: EEVblog #395 - World's Most Expensive Hard Drive Teardown
« Reply #19 on: December 06, 2012, 07:14:16 AM »
i just posted some technical info under the video . not going to repost here. now, as far as cost.. THis is not the worlds most expensive drive. That would have been The RAMAC ( the original harddisk... )

http://en.wikipedia.org/wiki/IBM_305_RAMAC

Below a picture fo the entire drive. left the platters ( 52 of them , right the cabinets with electronics to tame this beast. )
-50 user disks (dummy disks at end to reduce turbulent buffeting)
-100 sides, 100 user tracks per side (2 test only tracks on inside and outside)
-5 sectors per track, 100 characters per sector
- Grand total of 50 disks x 2 sides/disk x 100 user track/side x 5 sectors/track x 100 char/sector = 5,000,000 characters

The bootloader of a modern OS wouldn't even fit on this thing... Take a picture with a 10 Megapixel camera of it in JPEG and you can't store it on this thing ...

The computer history museum has ony. The drive was invented here in San Jose and the were built in the Cottle road facility , where , today , they are STILL building and designing harddisks. Now part of Hitachi storageworks. ( IBM sold their drive business to hitachi ) HGST.
The old building was torn down and is now a Lowes home improvement sotre , but as part of the deal they had to decorate their building using the IBM tile pattern , put a memorial pagoda with images and a baseball field called RAMAC park. :
« Last Edit: December 06, 2012, 07:26:48 AM by free_electron »
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Offline Lightages

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Re: EEVblog #395 - World's Most Expensive Hard Drive Teardown
« Reply #20 on: December 06, 2012, 07:23:41 AM »
In the early 90s, IBM was doing the research into the materials used in the hard drives we have today. Their research center in San Jose California was using a very specifically designed materials research system designed to make giant magnetic resistive effect materials and high temperature superconductors. It is this research that resulted in the very small read heads that make the smaller drives now possible.

The picture attached shows their research system under development in 1992 at a company in Canada. If anyone is interested in what the system did or its capabilities, just ask!
https://www.youtube.com/watch?v=Xsj1UWol7l8
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Offline And!

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Re: EEVblog #395 - World's Most Expensive Hard Drive Teardown
« Reply #21 on: December 06, 2012, 07:27:57 AM »
Try to sprinkle a little bit of metal dust on a plate. Maybe tracks can be seen?
At 20MB 8" disk it was possible.

And
Spin it up ! Spin it up! Spin it up! ;)

It will be more difficult than running super high speed laser mirror motor (36m:00s):
EEVblog #303 - Photocopier Extreme Teardown


But it will be scary :D
« Last Edit: December 06, 2012, 07:29:40 AM by And! »

Offline dexters_lab

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Re: EEVblog #395 - World's Most Expensive Hard Drive Teardown
« Reply #22 on: December 06, 2012, 07:40:57 AM »
Dave you gotta get that actuator apart just for the magnets, those in the newer disks are puny in comparison as the newer voice coils are so much more efficient

Great video though, love seeing top of the line old tech pulled apart

Would also love to see the spindle motor powered up
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Online pickle9000

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Re: EEVblog #395 - World's Most Expensive Hard Drive Teardown
« Reply #23 on: December 06, 2012, 07:58:11 AM »
Too bad you didn't have some MICR toner, sprinkle a bit of the on the platter and the tracks would have shown up.

Offline mikeselectricstuff

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Re: EEVblog #395 - World's Most Expensive Hard Drive Teardown
« Reply #24 on: December 06, 2012, 08:05:13 AM »
as for taking the linear actuator apart.
looks to me like there is a "hinge like" mechanism on each side with a pin going length wise
down / through the side ?

what do you mean you dont have pneumatic impact tools in your shop ??

;)
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Offline Pentium100

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Re: EEVblog #395 - World's Most Expensive Hard Drive Teardown
« Reply #25 on: December 06, 2012, 08:44:12 AM »
It's a shame they don't make 5.25" (or bigger) drives anymore. With modern data densities the capacity would be awesome.

Offline Robreeves

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Re: EEVblog #395 - World's Most Expensive Hard Drive Teardown
« Reply #26 on: December 06, 2012, 08:58:26 AM »
Very similar to the first machine I was paid to program in 1973.  IBM 1440 (disk version of the 1401).  The disks were removable, 20000 sectors of 100 bytes = 2mb. We had 5 of them. Oh, and the big day is when we upgraded memory from 8k to 12k

Online EEVblog

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Re: EEVblog #395 - World's Most Expensive Hard Drive Teardown
« Reply #27 on: December 06, 2012, 10:51:13 AM »
Dave! How can you not take apart the linear actuator?

I tried to lever it open with a big screwdriver, and I couldn't.

Dave.

Online EEVblog

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Re: EEVblog #395 - World's Most Expensive Hard Drive Teardown
« Reply #28 on: December 06, 2012, 10:54:57 AM »
As to the air lines, those are not Halon, but for pressurised clean dry air from a built in compressor and filter drier pack in the drive bay, used to circulate clean air into the drive case and remove the hot interior air.

I am assured by the original owner that it was connected to cooled pressurised halon. Yes, it's used for cooling, I forgot to mention that.

Dave.

Online EEVblog

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Re: EEVblog #395 - World's Most Expensive Hard Drive Teardown
« Reply #29 on: December 06, 2012, 10:58:10 AM »
as far as cost.. THis is not the worlds most expensive drive.

Never let the facts get in the way of a good keyword searchable video title  ;)

Dave.


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