* Posts by Charles F J Barnes

5 posts • joined 13 May 2008

DataSlide reinvents hard drive

Charles F J Barnes

Surface calcs.. etc...

The basic 'unit' of a dataslide is a double-sided media plate with a head matrix on each side, two of these are then help in opposition to each other and driven by the same signal anti-phase,(to acoustically couple and therefore remove any sound from the oscillation) so the working 'unit' has four media surfaces, because this unit is a few mm in depth it is possible to fit at least 2, and in a full height form factor 3, of them into that space. I believe that this may help with capacity calculations, also read and write is done on each half cycle.

The immediate advantages are to Tier 0 as observed.

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Charles F J Barnes
Boffin

Surface contact and alignment and electro-mechanical

The surfaces are full face contact with a coating of taC (tetrahedrally amorphous carbon) this is simplistically a solid mixture of sp3 diamond and graphite, with a CoF of 0.01 - 0.001 depending on doping with nitrogen and humidity, it is therefore one of the hardest and slipperiest materials known. It has a very high heat transfer rate and in long term tests has shown no detectable heat from friction, no stiction and no detectable wear in high abrasion tests. The effective 'fly-height' of the heads is the RMS of the surface of the head matrix, this can be provided by Corning as a raw material at <1 nanometre RMS and <10 nanometre curvature.

The head matrix plate and the media surface are kept aligned in the X axis an active piezoelectric actuator and by sprung loaded side bearings, also coated in taC. Essentially a 'square bearing' it is also important to consider that apart from the ULE glass, the amount of skew necessary to miss-align mechanically is quite large over the entire slide.

It may appear pedantic, but the drive is a direct step voltage driven Oscillation, not a vibration, the former is deterministic and can be predictably controlled, the later is neither.

Curiously and often counter-intuitively, solid state comes with a built in cause of failure, with many recent small feature size chips having as little as 10,000 re-writes, obviously this is not an issue for your photos and music etc. on a memory stick, but at the Tier 0 of a server stack, logging, meta data and snapshot management can mean that this can be used very rapidly, wear-levelling is used, but this also comes with re-write issues.

Dataslide media is standard magnetic media and has a very well proven history in terms of longevity.

Also piezoelectric actuators are a very mature technology and have been tested for many billions of cycles.

There are in fact 'flat-pack' products, they do not however deal with the issue of re-write, power consumption, price/performance or heat dissipation(which becomes a more significant issue as the heat produced in inner layers has to be removed through the outer layers..

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Charles F J Barnes

--- Designing hardware with a buzz

My apologies, the capacity is rather deep in the technical 'stuff'', the current capacity at current sampled head feature size of 1 micron , is 80 GBytes for a 2 and 1/2 inch form factor, the road map is 2 Tbytes on two lithography 'turns', which the IC people tell me is pretty unambitious... ?

Incidentally the potential problems of noise from any oscillation, is dealt with by having two units (consisting of one media plate and two head matrix surfaces) physically coupled with an anti-phase drive signal, this effectively acoustically couples both and the result is a silent drive.

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Charles F J Barnes
Boffin

Reply...

To deal with each of the above in order:

It is not a drum, it is a (very) flat rectangle of Corning ULE glass, which has the mechanical properties of Aluminium and a CTE of 10-9, hence no thermal instability or miss-alignment issues.

Actually a read write head is a 'point' source, I believe a point or locus, is by definition dimensionless ?, a line, one dimension, a square, two dimensions etc....two dimensions are one of the foundations of relational calculus, hence SOL and most Databases, hence archtecturally useful in such applications..

Al the heads are lithographed (at micron feature size) in a very similar manner to LCD production using precisely the same techniques as current HDD heads, however by using a novel (hence patented), but fundamental magnetic flux concentration principle the flux produced is both orthogonal to the head matrix surface, but also ideal for perpendicular media and significantly more efficient per unit of current.

The huge reduction in process steps and component parts means that it will be possible to manufacture at a similar price point to current high end HDDs, and especially if one takes into account the short stroking and switching off of the cache of such drives at Tier 0.

The novel flux 'focus' and the simplicity of the design means most of the lithography is self-aligning, hence very low mask costs.

There is a very considerable amount of 'prior -art' in the recent decades to attempt just this, however the majority of these were concentrated on solving problems of particularly thermal miss alignment, the use of the Corning ULE glass removes this issue.

The heads are all fixed, the entire matrix moves, about 100 microns, the random access is achieved by time-slice switching during each half oscillation.

Similar to any number of head per track etc... devices, but in fact a head per sector and essentially a RAM mapped architecture.

The current first product feature size and surfaces, provides between 40 and 80 GBytes, this size of device at Tier 0, at very low energy per IOPS is a premium and growing market, also it is plug and play, can be put into a server rack in the DMZ and let your SysOps loose..... it won't be long before if moves down the storage Tiers and curiously that maps to our proposed manufcaturing road-map :-)

True, a disk wastes about half of the available linear space to put media into than HDD case, not only that but it wastes the 'depth' of the case, which dataslides can fill with head and media units to give increased capacity in a standard device, hence 'spatial' as opposed to 'areal' density.

There is no seek, since each head is located over the sector of media (and data) which it is registered to, it does however have a LATENCY of 0.5 ms at 1 KHz, also with some MRAM in the CMOS and some appropriate firmware it is possible to move this to much less.

Curiously, as to the order in which the various 'professions were introduced to the concept, this was actually invented by SysOps, tired of managing server farms.... scarily, the engineers are still very much in the ascendant :-)

The basic alignment process is done with piezoelectric actuators which currently are in any number of industrial applications and especially in the IC industry, nanometre accuracy is standard, and is a direct voltage step process.

Also the CTE of 10-9 means about an atom width per degree Kelvin I believe... so not an immediate problem...

In fact it is likely that the first product, because of the largest/optimal IC stepper size, will be a RAID device n each surface...

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Intel said to feed Google solid state drives

Charles F J Barnes
Happy

How about an HRD, or Hard Rectangular Drive,

Commentators may be interested to note Dataslide's developments of a magnetic media based storage with the architecture of RAM.....

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