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Everything I know about SSDs (2019)

kcall.co.uk

21–30 of 53 posts

Re: Everything I know about SSDs (2019)

#21
post #9

Earlier quoted context omitted.

I never heard of using a literal flash to reprogram EPROMs, but this wikipedia entry[1] makes your story for the origin of the term “Flashing” seem likely EPROMs are easily recognizable by the transparent fused quartz (or on later models resin) window on the top of the package, through which the silicon chip is visible, and which permits exposure to ultraviolet light during erasing. [1] https://en.m.wikipedia.org/wik…

It does look like all the references I can find point to engineers at Toshiba in 1980 coining the name, although Google ngrams shows some references to "flash EPROM" prior to 1980, so I can't help but wonder if the idea existed at least in some form prior to 1980

Looking into it, those references look miscategorized. It's some Zambian national report that's talking about 0.18um processes (aka, 180nm) in the same paragraph, which wouldn't have come out until the very late 90s.

Re: Everything I know about SSDs (2019)

#22

Something useful to know that wasn't mentioned: SSDs will corrupt data if sitting for extended periods without being powered on and thus should never be used for cold storage. "There are considerations which should be made if you are planning on shutting down an SSD based system for an extended period. The JEDEC spec for Enterprise SSD drives requires that the drives retain data for a minimum of 3 months at 40C. This…

Makes me wonder if those external SSD drives made by Samsung and WD/Sandisk take that into account and use different flash memory with better longevity without power.

Re: Everything I know about SSDs (2019)

#23

Something useful to know that wasn't mentioned: SSDs will corrupt data if sitting for extended periods without being powered on and thus should never be used for cold storage. "There are considerations which should be made if you are planning on shutting down an SSD based system for an extended period. The JEDEC spec for Enterprise SSD drives requires that the drives retain data for a minimum of 3 months at 40C. This…

Makes me wonder if those external SSD drives made by Samsung and WD/Sandisk take that into account and use different flash memory with better longevity without power.

Unlikely in the case of Sandisk, which is known for a recent bout of extremely unreliable external SSDs: https://arstechnica.com/gadgets/2023/08/sandisk-extreme-ssds...

Re: Everything I know about SSDs (2019)

#24

Something useful to know that wasn't mentioned: SSDs will corrupt data if sitting for extended periods without being powered on and thus should never be used for cold storage. "There are considerations which should be made if you are planning on shutting down an SSD based system for an extended period. The JEDEC spec for Enterprise SSD drives requires that the drives retain data for a minimum of 3 months at 40C. This…

Relevant: Nintendo 3DS and Switch game carts go bad unless played https://news.ycombinator.com/item?id=39367506

Re: Everything I know about SSDs (2019)

#25
post #5

I always thought 'flash' was a holdover from early reprogrammable ROM technology, non-volatile memory that you could erase by literally flashing a literal flashbulb over a little window on the chip. I would've sworn in a court of law that I recall this being called "flashable" memory, that erasing it was called "flashing" it, and reprogramming it in general was called "reflashing" in a sort of synecdoche. And I'd hav…

I always thought that "flash" memory was named for EEPROM's erase speed compared to EPROM erase speed (less than a second versus 20+ minutes).

EPROM has erase as the first word in the acronym, so everyone just said "erasing" the PROM when they put the chip in the UV eraser.

Wikipedia lists finer differentiation between flash memory and EEPROMs.

see https://en.wikipedia.org/wiki/EEPROM#Related_types

Re: Everything I know about SSDs (2019)

#26

Something useful to know that wasn't mentioned: SSDs will corrupt data if sitting for extended periods without being powered on and thus should never be used for cold storage. "There are considerations which should be made if you are planning on shutting down an SSD based system for an extended period. The JEDEC spec for Enterprise SSD drives requires that the drives retain data for a minimum of 3 months at 40C. This…

Makes me wonder if those external SSD drives made by Samsung and WD/Sandisk take that into account and use different flash memory with better longevity without power.

If anything, I would expect consumer SSDs to use the cheapest/lowest grade of flash available.

Re: Everything I know about SSDs (2019)

#27

I've heard SSDs are more likely to "fail fast". Can anyone recommended utilities that monitor and warn before SSD failures?

My SSDs show SMART attributes, which can be used as a rough indicator of health, but really the only strategy I've found to work well for my peace of mind is to use redundancy. Concretely, I use ZFS with a zpool with 2 SSDs in a mirror configuration. When one dies, even if it's sudden, I can just swap it out for another one and that's it. My vulnerability window starts when the first SSD fails and closes when the mir…

Did you stagger the power-on times? Otherwise you could get tightly correlated failures.

Re: Everything I know about SSDs (2019)

#28
11 years ago, I did a 3 hour 'Introduction to Solid State Storage' at LOPSA-East 2013 that also covered how spinning disks worked, if anyone is interested.

https://www.youtube.com/watch?v=G3wf1HMr6b0

The SSD content starts at around 1 hour in: https://youtu.be/G3wf1HMr6b0?si=5kdNeLGafrrU6Gmy&t=3573

Re: Everything I know about SSDs (2019)

#29

I've heard SSDs are more likely to "fail fast". Can anyone recommended utilities that monitor and warn before SSD failures?

My SSDs show SMART attributes, which can be used as a rough indicator of health, but really the only strategy I've found to work well for my peace of mind is to use redundancy. Concretely, I use ZFS with a zpool with 2 SSDs in a mirror configuration. When one dies, even if it's sudden, I can just swap it out for another one and that's it. My vulnerability window starts when the first SSD fails and closes when the mir…

[deleted]

Re: Everything I know about SSDs (2019)

#30
post #27

Earlier quoted context omitted.

My SSDs show SMART attributes, which can be used as a rough indicator of health, but really the only strategy I've found to work well for my peace of mind is to use redundancy. Concretely, I use ZFS with a zpool with 2 SSDs in a mirror configuration. When one dies, even if it's sudden, I can just swap it out for another one and that's it. My vulnerability window starts when the first SSD fails and closes when the mir…

Did you stagger the power-on times? Otherwise you could get tightly correlated failures.

They are about 25 hours apart, which isn't very large I'll admit.

Thankfully, the serial numbers aren't too close to each other, so I'm hoping they aren't part of the same batch.

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