
The Evolution of Disk Storage and an Introduction to NVMe - workrockin
https://www.linuxjournal.com/content/data-flash-part-i-evolution-disk-storage-and-introduction-nvme
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sliken
My dad had a 256bit memory module on his desk. Made out of sandwich of two
pieces of glass and 16 vertical and 12 horizontal wires. Each intersection had
a small ferrous ring.

Around that time he was programming and early computer and you could actually
hear the memory bits changing. He was excited listening to it, figuring each
click was a loop. Then her heard a different sound and realized he as hearing
instructions and not loops.

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jcoffland
Some really early computers stored bits in waves in mercury. A series of waves
would be started at one end of a tube full of mercury and they would be read
back when they arrived at the other end. The memory of course then had to be
refreshed. Core memory was however much more successful.

[https://en.m.wikipedia.org/wiki/Delay_line_memory](https://en.m.wikipedia.org/wiki/Delay_line_memory)

~~~
agumonkey
Same idea was used between satellite and ground, wave was used as a memory
that could be reused when back to station.

~~~
winrid
Holy crap that's so cool. Thanks for that info.

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agumonkey
Some teacher that worked for the french ministry in the 80s told us that. It
makes sense but I never found data on it. I'm not 100% sure it was done
because he was a bit of a big mouth but at the same time he was in the field
for decades so..

~~~
winrid
ah yeah I haven't found anything. Still a cool idea, however I'd imagine you'd
have issues with data loss.

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spectramax
I am surprised the article doesn't talk about Optane technology:
[https://en.wikipedia.org/wiki/3D_XPoint](https://en.wikipedia.org/wiki/3D_XPoint)

~~~
Nursie
Is Optane really 'all that' compared to other PCIe storage?

I know that Intel are positioning it as some sort of system accelerator, and I
know it does tend to score well in comparisons... but not "This is in a
completely different category" well, AFAICT.

What's special about it compared to, for instance, Samsung's NVMe offerings?

~~~
synack
Optane is persistent and bit-addressable, with mean latency under 1
microsecond, which is an order of magnitude faster than other SSDs.

I don't think the market has figured out the right use case for Optane yet.
The majority of desktop applications won't benefit from lower latency IOPS and
it's too expensive to use for general purpose storage on servers. It does make
sense for constant write or seek-heavy applications like database journals,
but most databases are optimized for doing bulk sequential reads/writes and
won't take advantage of Optane's bit addressable storage.

Intel's recently started shipping Optane DIMM modules that act like slow,
cheap, high density RAM. This is an interesting option as it allows in-memory
databases to be atomically persistent without having to add any code.

~~~
paulmd
It is actually significantly faster than traditional flash-based (NVMe/SATA)
SSDs for consumer workloads because flash performance falls off drastically at
low queue-depths, and almost all consumer workloads have low queue-depths.

A lot of consumer applications are not really optimized around super-fast SSD
storage in general. You end up with CPU bottlenecks initializing stuff and so
on. So in many cases Optane is not _noticeably_ faster than NVMe because the
bottleneck moves to the CPU instead of the SSD.

The real problem is price, of course. I'd gladly replace all my flash with
optane at $100/tb, but it's also an order of magnitude more expensive. Not
sure if that's just an issue of economies of scale not being there or what,
but I got a good deal on a 280 GB 900P (about $200) and that's enough super-
fast storage for the things that really matter to me. I use 1 TB EX920s for
the rest.

~~~
Rafuino
What do you use the 280GB 900P for in front of your 1TB drives? You're right
the bottleneck is often somewhere else in the system once you have modern
SSDs. The 280GB 900P is ~$0.89/GB [1] and 1TB EX920 is ~$0.15/GB [2] these
days, so the cost delta is not an order of magnitude (i.e. >10x).

What's funny to me is that the first consumer flash SSDs Intel released were
just over 10 years ago, and they were ~$7.44/GB with only 80GB capacities [3].
Things change quickly, eh?

[1]
[https://www.newegg.com/Product/Product.aspx?item=N82E1682016...](https://www.newegg.com/Product/Product.aspx?item=N82E16820167439)

[2]
[https://www.newegg.com/Product/Product.aspx?Item=N82E1682032...](https://www.newegg.com/Product/Product.aspx?Item=N82E16820326778&Description=ex920&cm_re=ex920-_-20-326-778-_-Product)

[3]
[https://www.tomshardware.com/reviews/Intel-x25-m-SSD,2012-15...](https://www.tomshardware.com/reviews/Intel-x25-m-SSD,2012-15.html)

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edoo
I use LVM and have enough storage that all SSD would be a little expensive so
for the last few years I've been using the block caching LVM feature with
mirrored NVME drives as a writeback cache to my large HDD array. It greatly
increases the performance of the storage with little hassle.

If haven't played with gluster for a few years but it has a tiered storage
feature so the most recently used files actually get moved onto the high speed
storage medium, which depending on your workloads might be even better,
assuming gluster is now performent and stable enough.

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ntw1103
I recently upgraded my laptop to a Thinkpad T470s, which supports M.2 NVMe,
and M.2 Sata. I upgraded from a 500gb NVMe drive to a 1TB M.2 sata drive. Why
do I say upgraded if it is slower? Well, in a laptop, power usage is hugely
important, as is heat. To prevent throttling on the CPU, less heat is better.
I did a lot of research, and found that the sata based M.2 drives consume less
power, and generate less heat. For my purposes the sata speed is sufficient.
:)

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brianpaul
FWIW, I believe Cray had an SSD option for the X-MP back in the early 80s.

~~~
wolf550e
From the brochure, it had a few million of 64-bit words worth of RAM that was
used as regular RAM ("central memory") and a lot more of ECC DRAM that was
used as fast storage ("SSD"). What was the API for the SSD? Was it mapped into
virtual memory as RAM, or did the ISA have I/O in,out opcodes for it with word
address, or did it use the API for disk storage, or what?

~~~
mechagodzilla
Even the Cray-1S supported it! I believe it was connected via a 128-bit wide
bus operating at the system clock speed (80 MHz in the case of the Cray-1),
which made it a ~10 gbit interface. From a low-level software perspective, it
was connected to a pair of DMA "channels" (1 input / 1 output), and there were
instructions to do bulk copies from SRAM->CHANNEL or CHANNEL->SRAM. It may
have used another slower channel pair as a command interface, but I'm not sure
(nor how COS or UNICOS exposed it from a higher level software perspective).

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sliken
Register latency is usually around 4ns (2.5-3.5 Ghz with a pipeline depth of
12-16). The article claims main memory latency is 7x more, which is around
24ns to 45ns. I tried to come up with plausible numbers that fix the 7x ratio
they mention.

These days main memory latencies are more around 70-80ns (single sockets) and
80-100 ns (dual sockets).

Being off by so much does make me wonder about the accuracy of the rest of the
article.

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3xblah
Will the expression "spin up" ever fall out of usage?

~~~
jyrkesh
Contrary to what others said, it will likely fall out of favor the way the
floppy icon faded for "Save" functionality in GUIs. It's everywhere until one
day you realize you can't find it in any of the apps you use every day.

~~~
SketchySeaBeast
Doing a quick survey of the apps on my machine, it seems like most have just
forgone the button altogether. For those that still have the button, the
floppy icon seems to still be there.

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Cthulhu_
Yeah, purely from memory here but it's not that the save icon went out of
fashion, but the concept of an icon bar or ribbon has gone; Microsoft's
current UI standard for their native apps still has a ribbon IIRC, but I feel
like that's one of the last vestiges. Using real world analogies went out the
window after skeuomorphic design was no longer a thing too.

Oddly enough, for me I had trouble adjusting to the 'folder' icon (or
referring to folders as folders), we grew up with the term "directory" and I
never had an association with anything physical with that.

