Newb questions on Palm file management

Archived from groups: comp.sys.palmtops.pilot (More info?)

Bill H wrote:
> I have aquired a couple of 'file-managers' - Teal Mover and MacFile.
> I am reasonably familiar with the MS file structures but I don't
> understand how things work in Palm OS. Is there an 'Idiots Guide'
> reference anyone would recommend?
>
> I seem to be missing some of the logic behind how Palm associates file
> extensions with file types and links this to shortcuts on the 'desktp'
> and applications.

OK, briefly, what you're looking at are Palm databases.

Databases come in two flavors: record databases, and resource
databases. You may recognized the extensions (on the desktop)
".pdb" and ".prc". A ".pdb" is a record database, and a ".prc"
is a resource database.

The main difference between a resource and a record database
is that in a record database, every record is numbered. So, if
you have 100 records, the first is always 0 and the last is 99.
Meanwhile, in a resource database, every record has a type
(which is a four-character string) and an index (which is a
number). So, for example, you might have the type 'tFrm' and
the index '1000', and that would be form number 1000. (A form
is kind of the Palm OS equivalent of a window.)

The practical difference is that all applications are stored in
resource databases. Resource databases can have other types of
data in them, but usually they are applications. Record databases
are usually data files (for instance, the address book and the
datebook each use a record database to store your contacts and
appointments), and they can never contain an application.

Also, every database (whether it's a record database or a resource
database) has, in addition to a name, a "type" and a "creator".
Both of these are four-character strings. The type specifies
what type of database it is ('appl' is an application), and the
creator specifies what application it goes with.

So, for example, the built-in Calculator application is a resource
database that has type 'appl' and has creator 'calc'. If it
had any data it would need to store, it would probably store it
in a record database with any type it wants and the creator 'calc'.

> Teal and MacFile give subtly different file lists and in MacFile some
> of them are greyed out. Puzzling.

I haven't used McFile in a long time, but it's possible the
greyed-out ones are databases that are stored in ROM. In some
file manager programs, you can choose to see databases in RAM
or those in ROM and RAM. Obviously, those that are in ROM can't
be modified, so they're just there for reference.

> In Teal I also get a number of files wiith extensions including
> _frFR, esES and _deDE, which I assume are something to do with
> foreign language support. Can I just delete all the non _enUS files?

Those are most likely overlay files. An overlay is basically a
resource database that goes with an application and is used to
replace some of its stuff (strings and so on) with locale-specific
stuff. Which overlay is used depends on what language you've got
the device set to.

However, if you don't need them, you probably can't delete those
overlay files, because they are probably in ROM. The good news
is that if they are in ROM, then they aren't taking up any space
you could use for anything else, so there's no need to delete
them either.

- Logan

Archived from groups: comp.sys.palmtops.pilot (More info?)

On Tue, 19 Apr 2005 07:26:21 GMT, Logan Shaw
<lshaw-usenet@austin.rr.com> wrote:

>> Bill H wrote:
>
>>> I seem to be missing some of the logic behind how Palm associates file
>>> extensions with file types and links this to shortcuts on the 'desktp'
>>> and applications.
>
>Oh, I forgot one thing I wanted to explain, which is how the
>launcher works.
>
>Here's what it does. It looks for all resources databases whose
>type is 'appl'. These are resources databases that hold an
>application. Then, it opens up each of those resource databases
>and looks for a couple of special resources in them. One tells
>it the name the application should have in the launcher (which
>doesn't have to be the same as the database), and the other is
>a resource that contains the actual image of the icon itself.
>
>There are no shortcuts on the "desktop". The launcher just
>scans all databases for ones that look like they must be
>applications and displays the names/icons for each of those.
>
>Also, there are no folders. All the databases exist together
>in one giant "pool" (for lack of a better term). That's not
>as bad as it sounds because the type/creator system makes it
>easier to figure out which databases go with which applications.
>
>One other thing makes this a little more complicated: when
>you have something like an SD Card, those use the same type
>of filesystem (no databases, no type/creator system, etc.) that
>desktops use, so the Palm also has a separate system for dealing
>with those.
>
> - Logan

Thanks for the pointers Logan.

Bill