Re: Shutdown behavior and flash storage devices

From	Don Y <blockedofcourse@foo.invalid>
Newsgroups	comp.arch.embedded
Subject	Re: Shutdown behavior and flash storage devices
Date	2021-07-27 11:27 -0700
Organization	A noiseless patient Spider
Message-ID	<sdpj5t$7h3$1@dont-email.me> (permalink)
References	<sdhb29$ibh$1@gioia.aioe.org> <nnd$0a5908ee$3a9716e7@d5a763e0a23fc394>

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On 7/27/2021 10:44 AM, Jaded Hobo wrote:
> On 24-07-2021 17:19, Dave Nadler wrote:
>> Hi All - I'm wondering what other folks do about this issue...
>>
>> Consumer flash storage devices (USB memory stick, SD card, etc)
>> have a nice internal wear-leveling controller. When one does a write 
>> operation, lots of sectors may be internally rejiggered to provide uniform 
>> wear (so things that are never rewritten from the application point of view 
>> are actually moved around and rewritten). This activity is invisible from 
>> normal application's point of view, but takes some time. If the device is 
>> powered off during such activity, data corruption... So, its necessary to 
>> provide the device some time after the last write before it is powered off. 
>> Plenty of embedded stuff I've seen too often corrupts memory at power off, 
>> and of course the device manufacturers blame the memory manufacturers...
>>
>> So, how do you avoid this kind of corruption in your designs?
>>
>> Thanks,
>> Best Regards, Dave
> 
> A number of upper tier memory device manufacturers sell flash drives, USB 
> sticks, SS Sata drives and M2 drives with "UPS" capabilities. When they sense a 
> loss of power they will have just enough onboard juice to power down in a 
> controller manner.
> 
> I have used drives from InnoDisk ( 
> https://www.innodisk.com/en/products/flash-storage/ssd ) on Linux boxes inside 
> machines with hard on/off switches. With regular drives we'd see boot problems 
> after 20 to 30 power cycles, with the "UPS" protected ones we could do hundreds 
> of hard cycles without ill effect.

What's the (typical) price premium for that "feature"?

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Shutdown behavior and flash storage devices Dave Nadler <drn@nadler.com> - 2021-07-24 11:19 -0400
  Re: Shutdown behavior and flash storage devices Theo <theom+news@chiark.greenend.org.uk> - 2021-07-24 16:37 +0100
  Re: Shutdown behavior and flash storage devices Don Y <blockedofcourse@foo.invalid> - 2021-07-24 18:10 -0700
    Re: Shutdown behavior and flash storage devices Dimiter_Popoff <dp@tgi-sci.com> - 2021-07-25 14:18 +0300
      Re: Shutdown behavior and flash storage devices Don Y <blockedofcourse@foo.invalid> - 2021-07-25 09:20 -0700
    Re: Shutdown behavior and flash storage devices Dave Nadler <drn@nadler.com> - 2021-07-25 08:49 -0400
      Re: Shutdown behavior and flash storage devices Don Y <blockedofcourse@foo.invalid> - 2021-07-25 09:30 -0700
      Re: Shutdown behavior and flash storage devices Dimiter_Popoff <dp@tgi-sci.com> - 2021-07-25 22:51 +0300
        Re: Shutdown behavior and flash storage devices Don Y <blockedofcourse@foo.invalid> - 2021-07-25 13:27 -0700
          Re: Shutdown behavior and flash storage devices Dimiter_Popoff <dp@tgi-sci.com> - 2021-07-26 00:00 +0300
            Re: Shutdown behavior and flash storage devices Don Y <blockedofcourse@foo.invalid> - 2021-07-25 17:35 -0700
  Re: Shutdown behavior and flash storage devices kegs@provalid.com (Kent Dickey) - 2021-07-25 13:53 -0500
    Re: Shutdown behavior and flash storage devices Don Y <blockedofcourse@foo.invalid> - 2021-07-25 13:20 -0700
  Re: Shutdown behavior and flash storage devices Jaded Hobo <badboy@heaven.org> - 2021-07-27 19:44 +0200
    Re: Shutdown behavior and flash storage devices Don Y <blockedofcourse@foo.invalid> - 2021-07-27 11:27 -0700

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