AaronJ wrote:
Roy Schestowitz <newsgroups@schestowitz.com> wrote:
Hmmm... that's a small difference to be worth paying for. I never looked
into Noah Pro, but I will do so now.
Even though Noah Pro allows you to use the SD card for the dictionary database,
it still requires about one meg of internal ram for what it calls a 'vfs cache'.
Sadly, a VFS cache is a necessity if you want to get good performance.
(VFS is Palm OS lingo for the part of Palm OS that accesses files on
SD Cards.)
The OS does not cache reads from SD Card, so if you read the same thing
twice, it has to physically go to the SD Card twice for it in all cases.
This by itself is really, really bad.
What makes this worse is that, because the Palm runs on batteries, it's
very aggressive about putting the SD Card (and its controller?) into
power-saving mode. I'd say based on experience it probably puts the
SD Card into power saving mode after something like 15 seconds of
inactivity. And it takes like 1/2 a second to 1 second to come
out of power-saving mode. So, what could take a millisecond with
a cache will possibly take an entire second without one!
However, my experience in implementing my own VFS cache was that 256K
was plenty for my purposes. I know the larger you make the cache, the
better performance you get, but 1 MB seems a little on the high side
to me.
Shameless plug:
If you'd like to see a dictionary that only has a 256K VFS cache but
performs fine, check out Nexus at http://pocketsensei.com/nexus.php
- Logan
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