hxh167
Member
Registered: Feb 2001
Location: Penn State
Posts: 116 |
 Dave/ Kopsis answered questions.
Here are some answers from Dave/Kopsis for questions about the differences between VFS(Virtual File System) and PiDirect:
> Now that all the details of PiDirect is on their web site. i would
> like to know the differences between the two without all the jargon.
It's really tough to explain all this in non-technical terms, but I'll
give it a shot.
> 1. How are they similar?
Both solutions give apps a way to read data from the memory
card. PiDirect "tricks" the OS into thinking that one of the
directories on the CF card is built-in read only memory. VFS doesn't
do any tricks, it just gives apps a standard way to access data on the
memory card.
> 2. How do they work?
PiDirect is transparent to the applications. Databases stored on the
card are accessed by the applications just as if they were stored in
RAM (except no writing is allowed). VFS requires that applications be
designed to work with an removable storage memory card. Since it is a
Palm standard, any app written to use VFS functions will work with
SD/MMC cards on a Palm m50x, MemorySticks on a Clie, and CF cards on a
TRGPro. When we have a VFS solution for FlashAdapter, those same apps
will work with it.
Of course the app launcher is really just a regular Palm OS
application, so PiDirect will let the launcher "see" and run apps that
are stored on the memory card. VFS requires that the launcher
"understand" the concept of memory cards, so a third party launcher
(such as Launcher III or SilverScreen) will be required to launch apps
from CF via VFS.
> 3. WHat are the differences in functionality?
>
> 4. What are the pros/cons or advantages/disadvantages of each?
PiDirect lets existing apps use the memory card without their
knowledge. VFS requires that apps be "designed" to use a memory
card. The former has the advantage of making a wider range of apps
"memory card compatible", but the downside is that the methods that
existing apps use to access databases are *very* inefficient for
accessing data that is stored in files. Applications specifically
designed to work with a memory card understand the pros and cons of
getting their data that way and can be designed to access the data in
much more efficient ways. Lastly, PiDirect doesn't allow apps to write
to the memory card. That's not a problem for reference databases and
read only documents, but there are many cases where a read/write
solution is better. For example, I *predict* you will see a version of
AvantGo within the next year that will be able to store web content on
a memory card using VFS.
> 5. Which is better for large files and why?
Both have the potential to work equally well. However, PiDirect will
only work well with large files that are broken into many small
database records. Many files are like this, but some (such as
Mapopolis maps) are pretty much just one big record so PiDirect
becomes nothing more than an automover in that case.
> 6. If I have 1 MB of space left on my Visor and have a 5 MB document
> I want to view, would I be able to do it with any of these solutions?
As I indicated above, in the case of PiDirect, it depends on the
database format. If we're talking Aportis Doc format, then yes, you
would be able to view the 5MB doc on a Visor with 1MB of RAM free. But
the FlashAdapter can do the same now with CSpotRun, and future VFS
enabled doc readers will give you the same capability.
Now one last thing to keep in mind is that an application like MSMount
uses VFS functions to provide capabilities very similar to
PiDirect. So with VFS you have the potential to get the best of both
worlds.
--
- Dave Kessler
President - Kopsis, Inc.
http://kopsisengineering.com
|
05-31-2001 10:36 PM
Does MemPlug have a version of Noah Pro to support them? It's odd that I don't know where I can get it. Please tell me. As I know the only 3rd party software supporting them is CSpotRun except the softwares originally included on the module. Don't tell me about these PiDirect related softwares because I cannot find them and I cannot use them (I am a VDX user).
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