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SSD myths - write endurance
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image shows Megabyte's hot air balloon - click to read the article SSD power down architectures and acharacteristics
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what are the big storms in SSD right now?

The market is plowing through some heavy design issues with DIMM wars and a widening range of segmentation opportunities in all memories not to mention a new plot twist in DWPD with metascale advised, life-cycle fitted, virtually hardened flash endurance.

Many reference points in the memory storage framework which were long thought to be stable are now cracking apart like ice floes - while flurries of IP volcanoes are spawning new islands of cinder which may be too hot to safely reach for without a promise of cloud-hanging softly insulated boots, bridges and roadmaps.
which SSD companies matter?
If they've been written about here on then they've been important in some way or other.

A company which may be very significant in a specialist niche may be almost unknown by the mainstream market. But all the good technology ideas in the SSD market eventually bubble up to the surface and affect how unrelated products are designed and used.
how to find more stuff on this site?
The site search box below works well and there's an A to Z site map if you prefer.

Use the search box to find what's been said in the past about a company or an SSD technology idea. Everything on this site is about SSDs or storage so you don't have to worry too much about constructing clever search formulas to exclude irrelevant results.

It took 20 years for the SSD market to grow to 10 concurrent active companies.

That score was reached in 1999.

9 years later - in 2008 - that had grown to 100 companies.

2 years later - in 2010 - that doubled to 200 companies.

I stopped counting market active SSD companies when the score went past 600.

A lot of ideas have changed in that time.

Here are the key stories recorded as events unfolded and some stories revisited later.
SSD history

"The winners in SSD software could be as important for data infrastructure as Microsoft was for PCs, or Oracle was for databases, or Google was for search."
all enterprise data will touch an SSD

image shows Megabyte's hot air balloon - click to read the article SSD power down architectures and acharacteristicsIf you've ever watched the movie Black Hawk Down...

It's like the chopper scene...
Surviving SSD sudden power loss

pcie  SSDs - click to read articleThe enterprise PCIe SSD market has exploded and fragmented into many different directions.

And some big bang PCIe SSD business dreams have shrunk too.
what's changed in enterprise PCIe SSD?

SSD servicesSome companies are making it easier to do business with them - by offering services which make it easier to buy their SSDs.
services which sell SSDs

the SSD heresies
Why can't SSD's true believers agree on a single shared vision for the future of solid state storage?
the SSD Heresies

SSD jargon explained

Little words can have with big meanings in the world of SSDs.
SSD jargon explained

The arguments about flash in enterprise SSD accelerators have changed.

sugaring  flash for the enterprise First you learned about SLC (good flash).

Then you learned about MLC (naughty flash when it played in the enterprise - but good enough for the short attention span of consumers).

Now we're writing silly rhymes about endurance.
sugaring flash for the enterprise
(12 years of taste tests)

boom bust article
Why do semiconductor memory makers get into oversupply and lossy pricing?
an SSD view of memory boom-bust cycles

custom SSDsIf it cost more - no one would do it.

Custom is an important business differentiator in the way that SSD companies do business.
some thoughts about SSD customization

 data recovery articles

Apple vs FBI shows it's not that easy.
SSD data recovery stories

storage reliability articles and newsReliability is more than just MTBF...

and unlike Quality - it's not free.
storage reliability

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where memory goes - compression follows

by Zsolt Kerekes, editor - - August 19, 2016

Cache memory compression techniques and a survey of why and where they can be useful featured in a news story here in April 2015 and was part of the rethinking RAM in an SSD context industry trend which is sweeping across computer architecture.

But where can we find examples of such techniques being used?

A recent case is a new version of software from A3Cube - which relates to their RAM over FABRIC system.

Among other things - Fortissimo Foundation 2.6 now includes In-Memory compressed IO caching.


is data remanence in persistent memory a new risk factor?

maybe the risk was there all the time

by Zsolt Kerekes, editor - - August 3, 2016

In 1981 I noticed that the contents of the RAM on a couple of preproduction processor boards which I was playing around with retained substantially most of the test data patterns which I'd initialized them with - even after switching the power off.

(These cards were part of an intelligent IO system I'd co-designed and for which I was writing the firmware. I remember it well because I was using 2 separate in circuit emulators. One controlled by typing wth my left hand, the other with the right.)

storage test equipment and analyzersMy focus was checking the repeatability of the analog IO side of these systems (from digital to analog and back again) at room temperature before we put them in the temperature characterization ovens and ran interference tests but I was surprised that the memory remembered - because that really wasn't what I was expecting.

I noticed that whenever I repeated the power off and power back on again cycling (into what we'd now call a "cold boot" condition) most of the contents of the memory looked similar to what they had been before, instead of scrambled which is what I expected.

Sure there was some corruption - but most of the old data was clearly visible.

It was interesting - but so what? In my earlier work at a previous company similar things must have happened. But I had never noticed - due to using more primitive tools and working under much greater time pressure.

Hm - so RAM can remember data after losing power...

I tucked this away as an interesting thing to remember and didn't think about it for another 10 years. (That old memory was SRAM BTW.)

So - about 10 years later - in 1991 - I had a customer with ultra sensitive applications who absolutely, under no circumstances whatsoever would return an expensive processor - offsite for a planned logic upgrade.

This was one of those sites where they point a gun at you as they check your ID and look in under your car and bags.

Disk Sanitizers
disk sanitizers
Their rigid process was - if it's got memory on it (and this card had a lot of DRAM and a lot of processors) then it had to stay forever under their control once it had been used.

If it couldn't be fixed on site it would be destroyed (probably with a special mechanical shredder).

Remembering back to my earlier experience (in 1981) I concluded that my customer almost certainly had the ability to read cold memory contents themselves and they were not going to be amenable to any textbook waving engineer telling them something which they knew and I knew was patently false:- that RAM loses its data after being unpowered.

So the options we had at that time were:- to test things better before shipping them and - if repairs were needed - to figure out how they could be done on-site.

In those days I wasn't really into storage jargon.

And in the 25 years which followed that - during my cut and paste career as a publisher and editor of this publication and its predecessor - the term "remanence" (which is the jargon term for this) occurred rarely if ever - and when it did - was always in the context of ensuring the security of data in non volatile storage products such a hard disk sanitizers and autonomous data destruct SSDs.

Looking back from the solid state storage everywhere context of today it may be easy to conclude that I've had a very narrowly focused career.

I would counter that saying my horizons have been occasionally broadened with other storage media (which are sadly no longer with us) and other data related aspects such as stories about data recovery and software.

Having thought about these things in recent days - obviously while reading and writing about the shape of future memory systems architectures we might yet see - I thought - isn't it a bit strange that I haven't come across this angle (of recovering data from cold DRAM) in any of the stories here on the mouse site?

Maybe you imagined it? Or maybe you just missed it? I thought.

recovering data from cold DRAM

So I did a quick Google search this morning and was reassured to find that there some published literature on this topic.

The first example I found was a paper - Lest we remember: cold boot attacks on encryption keys (pdf) (2008) in which the authors did experiments on cooling memory with freezer spray to see how much data would stay intact for how long:-
  • 99.9% of bits after 60 seconds unpowered
  • 0.2% decay after 60 minutes
From which article I quote - "This suggests that, even in modern memory modules, data may be recoverable for hours or days with sufficient cooling." the article (pdf)

To which I would add - you can skip the cooling requirement and get a recoverability time of days if you use DSP techniques and play around with the RAM voltages.

So... what's the point of mentioning this now?

Having gone down this tour of memory lane and observing that if you're recycling servers then there's a security vulnerability in the DRAM on those processor boards - not just in the much better known HDDs and SSDs.

And BTW don't rely on encryption to protect the DRAM contents - because your processor and its memory contents are on good speaking terms.

My point is that - now we're seeing new types of persistent memory creeping into DIMM sockets. And not just the flash backed hybrids but flash as RAM too.

So now you've got terabytes of data in these sockets. (And depending on your workloads some of this data stays in place for days or even weeks without being swapped out.)

And when the power is switched off - even without recourse to freezer spray - the contents will be there - clearly visible to someone with the right forensic skills - for months or years - same as if it were on a hard drive.

This creates new doors of opportunity for those in the business of making sure that doors which are thought to be shut stay firmly closed.

encrypting memory controllers?

After posting the above I did some more looking around for related articles and found this - Defending Against Attacks on Main Memory Persistence (pdf) - which was written in 2008 by clever people at the Department of Computer Science and Engineering, Penn State University - which just goes to show that when it comes to SSDs you have to go back many years in time to find articles which discuss the hot topics of today.

Among other things in that paper the authors say:- "The introduction of NVDIMM memory invalidates a basic assumption upon which OS and application security is based."

They go on in that paper to discuss an encryption based memory controller "to ensure plaintext data is never written to the persistent medium." the article

Their context at the time was low capacity alt nvms but the ideas discussed will give you a foretaste of what to anticipate in new SCM DIMM wars products.
Hmm... it looks like you're seriously interested in SSDs. So please bookmark this page and come back again soon.
.... is published by ACSL founded in 1991.

© 1992 to 2016 all rights reserved.

Editor's note:- I currently talk to more than 600 makers of SSDs and another 100 or so companies which are closely enmeshed around the SSD ecosphere.

Most of these SSD companies (but by no means all) are profiled here on the mouse site.

I learn about new SSD companies every day, including many in stealth mode. If you're interested in the growing big picture of the SSD market canvass - StorageSearch will help you along the way.

Many SSD company CEOs read our site too - and say they value our thought leading SSD content - even when we say something that's not always comfortable to hear. I hope you'll find it it useful too.

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the background to machine learned endurance tuning

Does - what you call the SSD...
impact - who the SSD buyer will call?
Branding Strategies in the SSD Market

The enterprise SSD story...

why's the plot so complicated?

and was there ever a missed opportunity in the past to simplify it?
the elusive golden age of enterprise SSDs

DRAM latencySetting the scene for DIMM wars

The DRAM market's new clothes had long been invisible.

But the SSD market was too preoccupied with lower hanging storage fruit.
latency loving reasons for fading out DRAM

How committed (really) are these companies
to the military SSD business?
a not so simple list of military SSD companies

Can you trust market reports and the handed down wisdom from analysts, bloggers and so-called industry experts?

heck no! - whatever gave you that silly idea?
here's why

Why do SSD revenue forecasts by enterprise vendors so often fail to anticipate crashes in demand from their existing customers?
meet Ken and the enterprise SSD software event horizon

Who's got all the answers to help understand how all the changes in the SSD market are coming together?
no one and everyone and you too

These fast evolving critters haven't read what it says on your jungle bug spray.
the survivor's guide to enterprise SSDs

How will the hard drive market fare
in a solid state storage world?
a classic article

unraveling the unreal positioning of AFA startups
compared to EMC...

Now we're seeing new trends in pricing flash arrays which don't even pretend that you can analyze and predict the benefits using technical models.
Exiting the Astrological Age of Enterprise SSD Pricing

My long held view is that all the traditional ways of prediction can't help but understate the destination size of the SSD market.
The big market impact of SSD dark matter

How much investment does it take to achieve something big in the SSD market?
over 100 SSD VC funding stories

In my role as Occasional SSD Agony Aunt - I've spoken to people about the "SSD acquisition problem" at both ends of the game. Here's what I've learned.
3 Easy Ways to Enter the SSD Market

90% of the enterprise SSD companies which you know have no good reasons to survive.
market consolidation - why? how? when?

With hundreds of patents already pending in this topic there's a high probability that the SSD vendor won't give you the details. It's enough to get the general idea.
Adaptive flash R/W and DSP ECC IP in SSDs

"...Application-unaware design of memory controllers, and in particular memory scheduling algorithms, leads to uncontrolled interference of applications in the memory system"
Are you ready to rethink RAM?

"A critical test of whether you really understand the dynamics of a complex market like enterprise SSDs - is whether you can predict what rational buyers might do when offered new product options at the extreme limits of - for example - price."
Boundaries Analysis in SSD Market Forecasting

"You'd think... someone should know all the answers by now. "
what do enterprise SSD users want?

We can't afford NOT to be in the SSD market...
Hostage to the fortunes of SSD