[comp.sys.apple2] cdevs

wombat@claris.com (Scott Lindsey) (04/12/90)

In article <9004111222.AA14492@apple.com> TE880714@BANUFS11.BITNET (Stef Bracke) writes:

> In my spare time, I like to examine programs, like GS/OS...
> This time, I'm looking at the Cdevs.
> Somehow, I found out that it is possible to make the icon of a cdev
> appear during startup. Is this for the current Cdevs or for the ones to come?

It is possible currently: the only CDev from Apple to make use of it is the
AppleShare CDev.

> These Cdevs use an Icon fork, a Data fork and a Flag fork. (Excuse me, I have
> it wrong.). Isn't there a program to investigate those forks. (An Iconeditor
> maybe?)

Your terminology isn't quite right.  Files under GS/OS can have two forks:
Resource and Data.  The data fork is presently unused (reserved) for CDevs.
Certain resources are defined for CDevs, including its icon, flags, etc.

A standard icon editor (like Apple's or Dave Lyons' DicEd) doesn't look at
resources, so that won't help you.  There's not much in the way of resource
editors available; TML has one for use with their development system; Apple
had Little.Res (which is no longer available as far as I can tell).  Then
there's Rez and DeRez for APW, but they aren't much use for browsing or
tinkering.

> Also, Cdevs are stored different on mediums. Is it similar to the normal
> format but just with another Storage type number?

A CDev is stored in a forked file, which is a newly defined storage type;
while similar to the existing storage types, it is effectively two files,
one of which (the resource fork) has a reserved format (unless, of course,
you bring over a Mac file which has an entirely different resource map).

> Finally, how can I make a Cdev myself?
You need either Rez for APW or RezIIgs for MPW to convert your code into
the proper resource.

> Please, keep in mind, that it is extremely (costly) difficult for me to
> consult any GS/OS manual, or to phone or fax to the States.
> Any help appreciated.

Unfortunately, to do any of this right, you absolutely need access to
(at least) the Tool Reference Volume 3 (beta draft) and the File Type note
for $C7.  Development is tricky enough when you have all the proper
documentation.  Without it, you'd almost do as well by randomly aligning the
bits on a floppy and seeing what you get :-)

--
Scott Lindsey     | I dig iguana in their outer space duds
Claris Corp.      |    saying, "Aren't you glad we only eat bugs?"
ames!claris!wombat| DISCLAIMER: These are not the opinions of Claris, Apple,
wombat@claris.com |    StyleWare, the author, or anyone else living or Dead.

ericmcg@pnet91.cts.com (Eric Mcgillicuddy) (02/05/91)

I have finished testing ViM and am getting ready to release the thing. It
currently exists as a PIF with a cheesy Applesoft configuration program to get
it going. It has been suggested that I convert it to a CDEV  (like the System7
VM module). Trouble, I don't have a clue sa to how to convert a PIF to a CDEV.
I have read the Technote on cdevs and have Rez as well, but I can not make
heads or tails of what they are saying.

Could someone give me a blow by blow description of how one does this?
Preferably from personal experience.

Also, is there an Extended Control that allows the user to select a vloume
name from a list of online volumes? This allows me to ditch the Applesoft
thing and have the user configure from within the CDEV.

UUCP: bkj386!pnet91!ericmcg
INET: ericmcg@pnet91.cts.com