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Samsung expands DIY repair program, adds Galaxy S23 and Fold 5 in US

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Re: Samsung expands DIY repair program, adds Galaxy S23 and Fold 5 in US

#61

Post by ssl-3 »

malfist wrote: post #35
skyyler wrote: post #26

Earlier quoted context omitted.

Doesn't it degrade with use? I thought with modern wear leveling you get degraded performance for a long time before it just stops working, but I'm no expert. I'd love to learn more about this actually

It does degrade, but not performance. The degrading happens when blocks hit their wear limit and can no longer be used. Flash memory typically includes additional blocks to replace those that are at their wear limit, but that will eventually exhaust and then the drive will be in a failure state. This can sometimes be that the drive stops working, or that it shrinks it's capacity, but the bandwidth and access speed ch…

How does a storage device shrink in capacity, and by what mechanism is that shrinkage communicated with the filesystem?

Re: Samsung expands DIY repair program, adds Galaxy S23 and Fold 5 in US

#62

Post by vardump »

antongribok wrote: post #49
FirmwareBurner wrote: post #34

Earlier quoted context omitted.

Not sure if you're sarcastic or not, but SD cards have been absent from flagship Androids for about 10 years now. Wait till you find out the batteries are not swappable anymore.

Galaxy S10+ came out in 2019. I believe this was the last flagship to have a microSD card slot.

Galaxy S20 definitely has a microsd-slot. At least some models.

Re: Samsung expands DIY repair program, adds Galaxy S23 and Fold 5 in US

#63

Post by thebruce87m »

ssl-3 wrote: post #60
malfist wrote: post #43

Earlier quoted context omitted.

Flash memory does not erase during user actions. TRIM is done async

Flash memory is always erased during user-initiated writes in instances where trim is not used, or when there are not enough known-erased blocks to hold the write -- for whatever reasons these conditions may exist. At a low level, a block of flash can't be written without being first erased. It might have been erased previously (which is ideal), but it might also might need to be erased immediately (which is much slo…

> Flash memory is always erased during user-initiated writes in instances where trim is not used

Great answer but slight nit pick: In my world (embedded) the flash on (some? dare I say most?) microcontrollers is only erased when you specifically tell it to erase. You can write to sectors multiple times without erasing. You can even write to the same word multiple times, as long as you only want to turn 1’s to 0’s. If you want to turn any 0 to a 1 in the whole sector then that’s when the erase comes in.

This gives interesting use-cases where you can count up using individual bits without a time-consuming/power-using/cycle-consuming erase.

Re: Samsung expands DIY repair program, adds Galaxy S23 and Fold 5 in US

#64

Post by malfist »

ssl-3 wrote: post #61
malfist wrote: post #35

Earlier quoted context omitted.

It does degrade, but not performance. The degrading happens when blocks hit their wear limit and can no longer be used. Flash memory typically includes additional blocks to replace those that are at their wear limit, but that will eventually exhaust and then the drive will be in a failure state. This can sometimes be that the drive stops working, or that it shrinks it's capacity, but the bandwidth and access speed ch…

How does a storage device shrink in capacity, and by what mechanism is that shrinkage communicated with the filesystem?

That's determined by the firmware and the manufacturer.

Flash isn't like disks. You don't write to a block that's on a certain cylinder on a certain platter. You write a block and the memory controller determines where it will be stored, usually based on some wear leveling algorithm.

It's one of the reasons you can't securely delete a flash drive.

Re: Samsung expands DIY repair program, adds Galaxy S23 and Fold 5 in US

#65

Post by ssl-3 »

malfist wrote: post #64
ssl-3 wrote: post #61

Earlier quoted context omitted.

How does a storage device shrink in capacity, and by what mechanism is that shrinkage communicated with the filesystem?

That's determined by the firmware and the manufacturer. Flash isn't like disks. You don't write to a block that's on a certain cylinder on a certain platter. You write a block and the memory controller determines where it will be stored, usually based on some wear leveling algorithm. It's one of the reasons you can't securely delete a flash drive.

The question remains.

Handwaving about how flash is different than disks isn't an answer to how shrinkage is conveyed to the filesystem (and isn't a meaningful differentiator anyway, since common spinny-disks haven't been 1:1 mappings for well over 3 decades, themselves).

Re: Samsung expands DIY repair program, adds Galaxy S23 and Fold 5 in US

#66

Post by ssl-3 »

thebruce87m wrote: post #63
ssl-3 wrote: post #60

Earlier quoted context omitted.

Flash memory is always erased during user-initiated writes in instances where trim is not used, or when there are not enough known-erased blocks to hold the write -- for whatever reasons these conditions may exist. At a low level, a block of flash can't be written without being first erased. It might have been erased previously (which is ideal), but it might also might need to be erased immediately (which is much slo…

> Flash memory is always erased during user-initiated writes in instances where trim is not used Great answer but slight nit pick: In my world (embedded) the flash on (some? dare I say most?) microcontrollers is only erased when you specifically tell it to erase. You can write to sectors multiple times without erasing. You can even write to the same word multiple times, as long as you only want to turn 1’s to 0’s. If…

Solid nit pick. I appreciate it.

(And somewhere in the back of my head I knew of this method of writing useful things to flash. It certainly has at least a couple of efficiency advantages that can be important in some cases, even if they're not the kinds of things that would be important or even usable with a consumer-oriented flash device that is operated from a high level.)

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