2.11BSD on two RL02 drives? Probably not, but...

Christian Corti cc at informatik.uni-stuttgart.de
Fri Aug 4 09:07:04 CDT 2017

On Fri, 4 Aug 2017, Noel Chiappa wrote:
> But are SD cards really that unreliable? If they were, I'd have thought I'd

Yes they are. Just have look around in the world of cameras and 
smartphones where people suffer from losing their photos just because an 
SD card decides to fail. I have several failed SD and CF cards, as well as 
USB bars. And many flash cards will fall into a read-only mode when errors 
cannot be corrected anymore, in contrast to real disk drives where you can 
skip the bad areas.

I just had a look on some datasheets for industrial SD cards. ATP gives a 
value of 384 TBW (terabytes written) for SLC and 38.4 TBW for MLC devices. 
For a 32 GB SD card, this means a max. write count of 12,000 for a byte. 
SanDisk give 192 TBW for their Industrial XT, that is even worse. A 64 GB 
SD card would only support 3000 writes per byte before you begin to 
play roulette...

Soooo... here I come again with my preference of PATA/SATA drives. If you 
really want a non-rotating media, then I suggest that you use SATA SSDs.
Hence why I prefer a controller/interface with PATA/SATA connectors ;-)
You are totally free in using rotating or non-rotating media.


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