
SanDisk crams 400GB into a microSD card - jonbaer
https://www.engadget.com/2017/08/31/sandisk-400gb-microsd-card/
======
userbinator
This is almost certainly going to be 3 or 4 bits per cell flash, which has
exponentially worse retention and endurance than 1 (SLC) or 2 (MLC) bits per
cell for only a multiplicative increase in density[1], and requires even more
(fragile) algorithms for error correction/avoidance/longevity. I wouldn't be
surprised if this "400GB" was actually 512GB (2^39 bytes, or "512 real
gigabytes"[2]) of raw capacity, with 112GB of spare area. OK for short-term
"transfer" storage, like the camera applications alluded to in the article,
but definitely not for long-term archival or maybe even medium-term. Perhaps
there should be a separate category for devices like this:
"pseudononvolatile".[3]

To parallel an old saying: "big, fast, reliable - pick two."

[1] The terms "triple-level cell(TLC)/quad-level cell(QLC)" are entirely
misleading, since they imply only a multiplicative increase in the actual
number of distinct voltage levels in each cell. One wonders if they are
deliberately downplaying the associated reliability issues by making it seem
multiplicative instead of exponential. These should really be called triple-
bit/quad-bit or eight-level/sixteen-level cells.

[2] Remember when flash disks had real binary capacities? I have a 64MB USB
drive that really contains 131,072 user-accessible 512-byte sectors --- and
it's still working, because it's SLC flash.

[3] I've worked with NAND flash over the years and noticed something
interesting: you can very easily find datasheets for SLC and MLC (2-bit)
flash, which give the endurance/retention. But there is very little on TLC
(3-bit) flash --- they're almost all NDA'd leaks, which a few years ago were
already rare, but seem to have mostly disappeared now --- and basically
nothing on QLC/4-bit. Why the secrecy? It makes one wonder if there's
something inconvenient about this high-density flash, that they don't want
people to know...

~~~
slackingoff2017
I think this is a short-term issue just because error correction is so good.
We have many error correction algorithms that approach the theoretical limit
for efficiency.

Eventually error correction will take more bits than it saves and the number
of levels per cell will stall.

I would say our SSD's are actually much more resistant to errors than hard
drives were. Because the error correction in spinning disks is generally crap.

With flash, manufacturers have been forced to include extremely good ECC
schemes because cells die all the time. Since errors are generally random and
happen in large numbers, the life of the drive becomes predictable instead of
the death cliff we used to see with spinning disks.

~~~
fooker
What does error correction algorithms have to do with whether the disk spins
or is solid state?

~~~
slackingoff2017
It just happens that hard drives still have crap error correction. Probably
because most of their failure modes are catastrophic anyways.

Part of it is also Sandforce. The flash to make SSD's existed a few years
before they came on the scene but they were the catalyst. They created a
sophisticated controller that could do very good error correction and wear
leveling, allowing the first practical SSDs to be built.

------
lisper
My first day working at Google back in 2000 they had just inked an exclusive
deal with a hard drive manufacturer for their brand new high-capacity 40 GB
drives. They had a 4U rack stuffed full of 25 of them, and everyone was
standing around oohing and ahing and saying, "Wow, that's a TERABYTE!"

Now the same storage is the size of a thimble.

~~~
tapirl
I remember I bought a 4.7GB Seagate hard drive, for $250, at 1997.

~~~
King-Aaron
I remember my Dad buying a 20MB drive in 1993 for around double that..

~~~
mchahn
I started a company, Corvus Systems, that sold 5 MByte hard disk drives for
$4000. We sold a zillion.

Of course the competition was 74 KByte floppies at the time.

~~~
EugeneAZ
At the time I copied games for ZX-80 on a tape recorder. One 90 min cassette
had 260KB of storage. And now IBM make a 330TB one.

~~~
yread
Back in my day we only had stone tablets which had space for just one dot. A
whopping 1 bit of storage! /s

------
jandrese
IMHO, the most likely use case outside of people who shoot a lot of RAW photos
is for people building appliances out of stuff like Raspberry Pis that needs a
lot of storage. Things like MAME cabinets, DVRs, security systems, and the
like. The $250 price point on these is obviously a barrier for now, but it
should come down reasonably quickly if history is any guide.

~~~
bhauer
As with previous capacities, another use case is to have your entire music
library available in your phone. I use one of the previous 200 GB uSD cards
with my whole music library. It's nice to have _everything_ available
_everywhere_ I go. Now even those with >200 but <400 GB of music are able to
do the same.

~~~
rsync
"another use case is to have your entire music library available in your
phone."

Unfortunately, almost all phones continue to support microSD cards "up to 32
GB". Some will (reportedly) work with 64 GB cards, but if I understand
correctly, others need hacks/tweaks to access >32 GB cards ...

~~~
SAI_Peregrinus
My phone and tablet work fine with 128GB cards. The phone is a Samsung Galaxy
S4 running Android 7.1.1, the tablet is an Amazon Fire HD 5th Gen. Any device
that supports sdxc cards must support up to 2TB. The exFAT filesystem is
required for these, so you can't use FAT32 anymore. sdxc host devices started
coming out in 2010, pretty much everything that uses sd cards these days has
support for them.

~~~
userbinator
FAT32 has an individual filesize limit of 4GB, but otherwise works fine for a
2TB partition:

[http://www.cdrlabs.com/images/stories/reviews/silicon-
power_...](http://www.cdrlabs.com/images/stories/reviews/silicon-
power_armor_a30/silicon%20power%20armor%20a30%20properties.png)

~~~
SAI_Peregrinus
Yes, but SDXC drivers don't necessarily support FAT32 on SDXC cards. The spec
only requires exFAT. SDHC used FAT32.

~~~
userbinator
That's interesting. It seems the SD specs (which include SDXC) are mandating a
specific filesystem. According to
[https://en.wikipedia.org/wiki/Secure_Digital#SDXC](https://en.wikipedia.org/wiki/Secure_Digital#SDXC)

 _Nevertheless, in order to be fully compliant with the SDXC card
specification, many SDXC-capable host devices are firmware-programmed to
expect exFAT on cards larger than 32 GB. Consequently, they may not accept
SDXC cards reformatted as FAT32, even if the device supports FAT32 on smaller
cards (for SDHC compatibility)._

That seems like a gross "abstraction layer violation" to me --- like making
SATA controllers which work with SATA6 HDDs only when formatted with NTFS. The
filesystem should have nothing to do with SD, which simply implements a block
device abstraction. No doubt Microsoft was involved in this ridiculousness...

~~~
derefr
"SD" is basically the name of a standard _stack_ , not a particular layer. You
can reformat an SDHC card to not be FAT32, but then it won't be an SDHC card
any more.

There _is_ a point to this: SD cards are used in all sorts of low-level
embedded applications, with firmware that uses very inflexible (usually
assembler) code to address the card. The assumptions about the SD wire
protocol + the FAT32 filesystem + even the particular location of the FAT
table on disk are all knotted together in these devices.

Because of this, it's not even just that SDHC requires FAT32; SDHC requires
FAT32 _done with a specific formatting tool released by the SD standards
group_. Because your OS might put the FAT anywhere, but the tool puts it in
exactly one place, and that's the place that dumb embedded devices expect to
find it.

------
pmoriarty
I wonder how their reliability is compared to a traditional spinning platter
drive, for the typical workload of a desktop.

It would be nice if I could ditch the bulky spinning hard drive (or even SSD
drive) and use a microSDXC card. I've tried that before, and while it did
work, they quickly (within maybe a month or two) wore out and got errors on
them. I can usually get at least 3 or 4 years out of a traditional spinning
platter drive.

~~~
sundvor
I was going to say something about reliability.

As impressive as this feat is, and it really boggles the mind, I've had a
large number of SanDisk MSDs fail on me before I switched to Samsung. I'm not
very likely to switch back.

~~~
unkown-unknowns
Conversely the only Samsung microSD card I ever had failed on me. I've also
had some trouble with SanDisk cards from time to time. My general experience
is that microSD cards are _okay_ but I'm not at all happy about them.

I'm doing a project soon involving a Raspberry Pi. I've used rpi for various
things before but the different thins time is that it's going to be installed
at the location of a client. I am quite nervous that the microSD card will
fail. For my own stuff I can easily write the image to a new card and it
doesn't matter. But with a client where they expect the thing I'm making to
work it would be painful to have it fail.

Is there some ready-made Linux distro for Raspberry Pi that is extremely small
in size and which is made to load it whole self into memory and not write back
to the SD card at all? It'd be extremely helpful to know about it if any such
distro exists. Preferably it should be based on Rasbian just slimmed down and
with logging etc removed. That way the kernel itself would be more reliable so
that it won't crash randomly for reasons that have otherwise been fixed in
Raspbian but which might not be in an independently maintained kernel.

~~~
ZenoArrow
First of all, it should be noted that it's now possible to boot from USB,
bypassing the need for a microSD card, though the feature is classed as
experimental:

[https://www.raspberrypi.org/documentation/hardware/raspberry...](https://www.raspberrypi.org/documentation/hardware/raspberrypi/bootmodes/msd.md)

You could also use network boot:

[https://www.raspberrypi.org/documentation/hardware/raspberry...](https://www.raspberrypi.org/documentation/hardware/raspberrypi/bootmodes/net_tutorial.md)

To answer your question directly, yes there are Linux distros that
minimise/eliminate SD card usage. Aside from being able to mount the SD
storage as a read-only device (like you can with live Linux CDs), there are
some minimal distros that boot to RAM. One example is Tiny Core Linux:

[http://tinycorelinux.net/welcome.html](http://tinycorelinux.net/welcome.html)

Latest RPi build is was released only a few months ago:

For Pi Zero:
[http://tinycorelinux.net/9.x/armv6/releases/RPi/](http://tinycorelinux.net/9.x/armv6/releases/RPi/)

For Pi 3:
[http://tinycorelinux.net/9.x/armv7/releases/RPi/](http://tinycorelinux.net/9.x/armv7/releases/RPi/)

As a last bit of advice, there are quite a few different storage options
available for the Raspberry Pi. Here's one that you may be interested in (you
can buy the hard drive seperately if you didn't want to use the Raspberry Pi
Zero):

[http://wdlabs.wd.com/products/pidrive-node-
zero/](http://wdlabs.wd.com/products/pidrive-node-zero/)

------
Koshkin
This modern uSD tech is astonishing, beyond any science fiction. I no longer
pay attention to the transistor sizes or the CPU clock rates, but the advances
in the data storage technology look amazing to me.

~~~
mansilladev
Same here. Clearly, it's the work of the devil.

------
th-ai
IF 'SanDisk made a 4 GB microSD card on July 2006, at first costing $99 (USD)'
[1] and in 2017 'SanDisk crams 400GB into a microSD card' (costing $250 USD)
THEN

In 2028, maybe a 40TB microSD might cost $300? (@10 years of mp4?) And by
2040, 4 PB petabytes? (@1000 years of mp4?) Who's gonna have time to watch all
that?

So much local client memory is coming. With less network dependency in more
local storage, will our apps process memories faster?

[1]
[https://simple.wikipedia.org/wiki/MicroSD#History](https://simple.wikipedia.org/wiki/MicroSD#History)

~~~
wingworks
But as time goes one video etc gets larger, e.g. 1080p to 4K, to 6K to 8K etc.
Usually, the extra space we get is used up soon.

~~~
eat_veggies
This might be another "64kB of memory should be enough for anybody"
prediction, but will we ever need to go past 8K resolutions? Even 4K is crazy
high resolution and anything higher feels unnecessary and pointless if our
eyes can't see smaller.

~~~
bentpins
If 360 video kicks off, we might see resolutions resolutions much higher than
8K that ensure the viewport is always 8K. 10 bit colour is something that
could get wider adoption. Also I'd assume bitrate will creep up with network
speeds and storage prices, to reduce compression artifacts.

------
hs86
If we put the economic part aside, what kind of storage density could we reach
with these in a 4U case? I mean something like a custom build Backblaze
Storage Pod [1] but for microSD cards.

[1] [https://www.backuppods.com/](https://www.backuppods.com/)

~~~
jandrese
Power and cooling requirements would likely prevent you from achieving
absolutely insane density I think. Plus, you would go broke trying to fill the
thing with $250 cards.

You could use smaller cards, but then you have the nightmare of trying to find
a stable supplier that doesn't have a ton of fakes in their supply chain.

Even then, your competition is 10TB HDDs, and you need 25 cards + card readers
+ cooling to match one drive. Performance is better, but probably not enough
to justify the expense.

~~~
std_throwaway
Your 10TB HDDs have a density of only 2.56e16 bits/m³ which is far inferior to
microSD cards.

PS: Your lack of faith disturbs me.

~~~
imtringued
Unless you have a fully automated SD card library (tape library for sd cards)
then you have to at least consider the volume of the smallest possible SD card
reader instead of taking just the SD card's volume.

~~~
std_throwaway
You could possibly connect them all with through holes or very thin PCBs. No
need for a library or a full reader.

------
jakobdabo
From 200GB to 400GB in two years, so Moore's law is still rocking.

Now I can place all my music files inside my player!

------
_acme
As opposed to the microSD card with the most capacity, what is the microSD
with the best reliability for use with, e.g., a Raspberry Pi?

~~~
StavrosK
The Lexar high endurance. If you want to find SD card reliability info, check
websites and videos that do reviews for dashcam SD cards. Their primary focus
is on reliability because they need the cards to be able to be written on
constantly without failing for a long time.

~~~
adrr
I run Lexar high endurance in my dashcam had issues with other cards but with
the Lexar cards. Its different technology(MLC) so it doesn't have the capacity
as other cards but gains in durability. If i remember it stores 2 bits per
cell instead of 3.

------
patrickfl
This is getting crazy! One thing I love about the microSD market is it (pretty
much) eliminates the need to upgrade your iphone to the 128/256/512 version
and pay $xxx extra when you can just keep one of these puppies, and even take
it with you to your next upgrade, or swap to Android etc.

~~~
hanklazard
Maybe a dumb question, but how are you using microSD with your iPhone?

~~~
kevin_thibedeau
There are cases with an integrated lightning -> SD adapter.

~~~
tinus_hn
You can only use the storage with the app that came with the adapter.

------
cmurf
On reliability, I've got a much smaller 32GB Samsung EVO microSDXC in an
adapter in an Intel NUC formatted Btrfs being used as rootfs for Fedora
Server, for 6 months with zero errors of any kind including regular scrubbing.

I think the latest iterations of these cards (at least brand name anyway) are
a lot more reliable than SD cards of yore. Those were meant pretty much
strictly as a FAT32/exFAT camera card that you only write to, read off all
files from, then reformat to reuse; and were not really meant as a random
access device, organizing files, deleting individual files, modifying them,
like what an OS would do.

I do highly recommend running f3 tests on whatever you buy, f3write followed
by f3read, to check for fake flash. There's a lot of fake flash out there.

~~~
nickcw
If you like testing your media then you'll probably enjoy:
[https://github.com/ncw/stressdisk](https://github.com/ncw/stressdisk) my
project to test media.

I test all my flash / hard disks with it and have sent plenty back over the
years which failed!

------
ChuckMcM
One of the things I was thinking about building was a write once logging
system. Even at the high levels of logging that I run on various servers it is
only 10s of megabytes per day which this kind of thing could absorb for years.
And as a write once system it would never erase (not even have the capability
of erasing) allowing for 'walking backwards' in the logs in the event of
intrusion or malicious behavior.

It would certainly be an interesting mail archive system as well.

------
samstave
do you have any idea how many microSD cards I have lost in my life...

I am less worried about reliability and more about "oh crap I lost another
one" \- but with 400GB - thats the risk of losing a lot of data.

~~~
mmagin
And they're too small to have a useful area for writing on.

~~~
samstave
Can't you just write to the MBR!

------
kazinator
> _That means it can hold up to 40 hours of full HD video, in case you were
> wondering._

Easily 100 to 200 hours of 1080p material, if we go with a bit rate in the
range of 2 to 4 gigabytes per hour.

------
jballanc
This raises the inevitable question: what's the bandwidth of a 747 full of
these cards?

