Date: Sun, 24 Feb 2019 08:34:49 -0600 From: Valeri Galtsev <galtsev@kicp.uchicago.edu> To: freebsd-questions@freebsd.org Subject: Re: Recover failed SD card Message-ID: <16fe9803-9978-df84-7534-d46803e8e08d@kicp.uchicago.edu> In-Reply-To: <1D49330E-F047-4F86-8F37-A54980624332@kreme.com> References: <2341a9ac-42aa-737e-441f-b69cccc826c6@netfence.it> <d5a35ea2-4730-1244-7448-8effa8aca8d8@kicp.uchicago.edu> <afed71c6-b3be-9144-5bc1-78663932e6f5@baywinds.org> <1D49330E-F047-4F86-8F37-A54980624332@kreme.com>
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On 2/23/19 6:46 PM, @lbutlr wrote: > On 23 Feb 2019, at 13:50, Bruce Ferrell <bferrell@baywinds.org> wrote: >> Unfortunately flash memory "wears out". There are spare storage blocks and logic to level wear by switching th the spares when main block failures are detected. > > Yeah, that’s good theory, but it’s not what has happened with mine. Genrally they fail in the first few weeks. Even if it takes longer, it is not like they have been written and rewritten many times. This isn’t a wear issue, it is an "SD Cards Break easily" issue. > With all statements like that I would really like to hear at least the following about failed devices: 1. brand and model of device that failed on you 2. the source (vendor) you got the device from The truth is that there is lot of garbage that is manufactured and sold, and flash cards are the ones that have really gross difference between good (proper) ones and bad ones. Finite number of write operations is in specifications od flash memory. Fatal failure after short use is not, and is an indication of garbage device. Another example in the same lines would be rechargeable batteries (specifically: 16340 LiPo were the ones I was getting for myself recently, and it took me quite some effort to pick the good ones - knocking on wood). Now, I use and used in my car camera (read: written and overwritten all the time I drive), no failures: 1. High grade Samsung 128GB 100MB/s (U3) MicroSD EVO Select; 2. This one I do not consider the best, but it survived at least 6 years of use in car camera: Micro Center class 10 Micro SD (32 GB) So, instead of generalizing, I would really like to hear the detailed information about _failed_ devises Just my $0.02 Valeri -- ++++++++++++++++++++++++++++++++++++++++ Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ++++++++++++++++++++++++++++++++++++++++
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