No surprise on memory

John Watlington wad at
Thu Dec 18 10:52:19 EST 2008

The soldered in NAND is also 14 times slower on writes and half
the speed of a good SD card.


On Dec 18, 2008, at 5:51 AM, John Gilmore wrote:

>> What about using a NAND partition as swap?  Has this ever been done?
>> Given that partition support is a recent development it seems  
>> unlikely.
> Swapping to the soldered-in NAND chips is a very bad idea.  It will
> tend to wear them out rapidly.  Even if you use load-leveling software
> (e.g. swapping to a file in a jfffs2 filesystem), the problem is that
> if you do start wearing out serious numbers of flash blocks, the
> laptop becomes toast; it requires a soldering iron and spare chips to
> fix it.
> A much more reliable scheme would be to swap to an SD card, if one is
> plugged in and contains a swap partition (or a file in its root called
> SWAPFILE).  See  Even a small,
> cheap SD card could double or triple the available virtual RAM space.
> And if an SD card gets worn out, you merely pull it out of the laptop,
> throw it away, and buy a new one (for a fraction of the original cost,
> since Moore's Law has been working in your favor in the intervening
> years).
> This doesn't solve the least-common-denominator problem of people  
> without
> SD cards -- but it does offer a user, or a deployment, a very  
> simple and
> relatively cheap way to solve most problems related to physical RAM  
> size.
> On the topic of memory overload in general:
> Older XO releases did much better things when they ran out of physical
> memory:  they tended to rapidly kill off some process, leaving the  
> system
> largely functional.  In 767, the system instead goes from usable to
> molasses-like in a period of seconds, then freezes totally for minutes
> or hours.  As far as I know, nobody has debugged why that changed.   
> The
> prior behavior was infinitely preferable.
> 	John
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