[HN Gopher] LightPC: A Resilient System Using Only Non-Volatile ...
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       LightPC: A Resilient System Using Only Non-Volatile Memory
        
       Author : giuliomagnifico
       Score  : 28 points
       Date   : 2022-04-25 16:31 UTC (6 hours ago)
        
 (HTM) web link (news.kaist.ac.kr)
 (TXT) w3m dump (news.kaist.ac.kr)
        
       | karteum wrote:
       | Are there no longer issues with regards to the limited number of
       | writes on flash chips before they wear out ?
        
         | wmf wrote:
         | I don't think this is about flash.
        
         | ncmncm wrote:
         | This is probably using the stuff Intel was putting in its
         | Optane non-volatile RAM.
         | 
         | Downside is, turning it off and back on again doesn't fix
         | anything.
        
       | bogwog wrote:
       | This is really clever, but it seems "obvious" in the sense that
       | it must have been attempted before, right?
       | 
       | > LightPC matches the performance of DRAM by minimizing the
       | internal volatile memory components from non-volatile memory,
       | exposing the non-volatile memory (PRAM) media to the host, and
       | increasing parallelism to service on-the-fly requests as soon as
       | possible.
       | 
       | If it really does match the performance of DRAM, then this seems
       | huge. Surely it can't be true? Maybe it's only true for small
       | amounts of memory?
        
         | wmf wrote:
         | There's plenty of previous work on NVM as main memory. This
         | looks like an incremental improvement. All real NVM chips I'm
         | aware of are slower than DRAM so the only way to match DRAM
         | performance would be to use more chips which has packaging
         | considerations.
         | 
         | NVM is mostly theoretical since XPoint is mediocre and nothing
         | else is available.
        
       | ncmncm wrote:
       | It would have sufficed to provide just enough battery or
       | capacitor to copy from regular RAM to non-volatile storage in
       | case of a power drop. For reliability, you just need to ensure
       | stuff is charged up again, on startup, before resuming.
        
         | wmf wrote:
         | Half the point of NVM was to be cheaper than DRAM, not more
         | expensive.
        
           | ncmncm wrote:
           | The point of NVM is to be NV. A few GB of DRAM for cache and
           | a super-capacitor would not increase cost notably, but would
           | eliminate any performance impact, and also give a more
           | reliable recovery.
        
       | bitwize wrote:
       | My prediction is that this tech will remain an unviable
       | experiment. Until Apple just goes ahead and integrates it into
       | the M3 chip at which point everyone on Hackernews will have to
       | have one.
        
       | xyzzy21 wrote:
       | Issue: NVM endurance limits.
        
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       (page generated 2022-04-25 23:02 UTC)