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Everything I know about SSDs (2019)

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Re: Everything I know about SSDs (2019)

#11

Post by 0xcde4c3db »

jmbwell wrote: 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…

Old-school windowed EPROMs need to be erased under a UV-C tube for something like 20 minutes. By comparison a flash memory block erase operation is practically instantaneous.

Re: Everything I know about SSDs (2019)

#12

Post by ThrowawayR2 »

jmbwell wrote: 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…

EPROMs were erased by many minutes of exposure to UV light, not a flashbulb, in a device called a UV eraser. I've never heard anyone refer to any operation on an EPROM as "flashing".

Re: Everything I know about SSDs (2019)

#13

Post by howard941 »

jmbwell wrote: 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…

Programming the windowed EPROMS was called burning. Don't ever recall hearing anything about flashing them for programming or erasure.

Re: Everything I know about SSDs (2019)

#14

Post by markhahn »

little hard to understand why it's worth explaining the details if you're going to gloss over the issue of endurance and erase cycle limits.

if you do very little writing, you have nothing to worry about with SSD endurance. just read-disturb.

do you do very little writing?

Re: Everything I know about SSDs (2019)

#15

Post by Eisenstein »

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 means that after 3 months of a system being powered off in an environment that is at 40C or less, there is a potential of data loss and/or drive failures. This power off time limitation is due to the physical characteristics of Flash SSD media's gradual loss of electrical charge over an extended power down period. There is a potential for data loss and/or flash cell characteristic shift, leading to drive failure."

* https://www.ibm.com/support/pages/potential-ssd-data-loss-af...

Re: Everything I know about SSDs (2019)

#16

Post by magnetic »

password4321 wrote: post #7

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 mirror is rebuilt. If something bad happens to the other SSD during that time, I'm toast and I have to start restoring from backup.

Re: Everything I know about SSDs (2019)

#17

Post by jmbwell »

ThrowawayR2 wrote: post #12
jmbwell wrote: 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…

EPROMs were erased by many minutes of exposure to UV light, not a flashbulb, in a device called a UV eraser. I've never heard anyone refer to any operation on an EPROM as "flashing".

Yep, "UV eraser" confirmed by an elmer I know. A unit with a drawer and a timer knob, he says you'd typically set for 30 minutes.

He says he does recall people calling it "flashing," but not until much later, by which time it would have been actual "flash" memory.

As for my own memory, I'm going to file this under Mandela Effect, cross-referenced under Things People Probably Told Me That I've Believed Since Before The Internet Was Available To Fact-Check!

Re: Everything I know about SSDs (2019)

#18

Post by radicalbyte »

sgerenser wrote: post #8
jmbwell wrote: 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 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…

These things were used in a number of computers from the early 90s, I have a few lying around for my Amiga.

Re: Everything I know about SSDs (2019)

#19

Post by d_sem »

jmbwell wrote: 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…

Anecdotally this was also what was told to me by (now retired) electronic engineers who worked in automotive embedded systems in the 80's/90's. The term flash was related to the process of UV exposure to erase memory. This was also humorously explained to me as the beginning of the end for system performance. You didn't need to prove out your system when you could just update your hardware after the fact. In a world of over-the-air flashing we have come a long way from fixed design elements.

Re: Everything I know about SSDs (2019)

#20

Post by monocasa »

howard941 wrote: post #13
jmbwell wrote: 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…

Programming the windowed EPROMS was called burning. Don't ever recall hearing anything about flashing them for programming or erasure.

Yeah, exactly. 'Burning' itself being a holdover from PROMs, where you'd literally burn certain fuses in the array to select bits.
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