Nokia N95-3 boots slower than N95 “classic”
November 1, 2007 by Dario Soltani
Found this youtube video by zgold, displaying something rather strange. When booting the new N95-3 (the American phone) and the old N95 classic, it seems the old phone is performing better.
I’m not sure if this is because of Demand paging (more info at Wikipedia), a technique used to significantly improve device performance by creating a big virtual RAM memory which in reality is handled by the ROM – the memory card. Demand paging seems to be one of the big improvments on the coming Nokia N95 8GB, which has been reported to support a limited version the technique.
Hopefully new firmware upgrades will make all our N95’s support Demand paging.
I believe that you’re mistaken about how demand paging will work under Symbian. I believe that the addresses are virtualized (hence the reference to virtual memory), however this will be used simply to load “pages” of an application’s code only as they are used. Hence time will not be spent loading unused regions of code and such code will not be taking up precious RAM.
I apologize if this is simply what you’re saying, however the part about the “memory card” and “ROM” is confusing. If by “memory card,” you are referring to the flash memory card, this is hardly ROM and I don’t believe it will be used as, say, a large swap space as the result would most likely be quite slow. The presentations from Nokia about demand paging have emphasized *increased* speed and better use of scarce memory.
I believe that you may be confusing demand paging with virtual memory applications that increase the apparent memory by swapping out to secondary storage. This is similar, but never does the swapping out part — it only delays loading of read-only code blocks (and possibly throws away long unused pages to be reloaded, if needed, again later).
Is it possible that the N95-3 is booting more slowly because it’s loading more things at boot time?
Weisen, you’re a source of gold. I realize I’ll have to study demand paging further and perhaps write a post on how it works. I don’t understand, do you mean the phone executes code in realtime, or are we talking about compiled code here?