Mac OS X Metadata - Apple: 1, 9K Users: 0 [Archive]

JCS

Sep 26, 2002, 02:02 PM

Well John, "behaves correctly" could theoretically mean, that in the current build (bitter grape or however the next version is supposed to be called) everything is implemented and working fine.

As I posted to another board:

Well, "Closed/Behaves Correctly" can be interpreted several ways.

Maybe Apple didn't think the user demand justified any changes, in which case perhaps more user feedback will help. This is why there's a link to the Mac OS X feedback form (http://www.apple.com/macosx/feedback/) on the updated proposal web page.

On the other hand, maybe Apple decided the current system is best, regardless of any volume of user feedback, in which case we're kind of screwed.

Finally, maybe Apple has Big Plans for this area, but is not willing to reveal them at this time. I'd like to believe that, but better safe than sorry, IMO, so it's time to hit that feedback form... :)

OAW

Sep 26, 2002, 04:34 PM

Originally posted by JCS:
Well, it looks like Apple closed the bug filed as part of the Mac OS X metadata proposal. The close message? "Closed/Behaves correctly." *sigh*

For more information:

http://homepage.mac.com/jcs/.Public/metadata.html

John,

We've discussed this before over on Arstechnica .... and my position remains the same. I agree with you that it would be better if OS X only relied on extensions if there was no other metadata available. Having said that, I again must state that the current implementation is quite functional and very usable on a practical basis, and is much better than the Windows implementation.

Quite frankly, I believe that the most ardent opponents of the current implementation are coming from an "It's the principle of the thing!" mentality. That is, they come up with contrived examples such as this ...

http://homepage.mac.com/stewer/visu/files.gif

... to bolster their argument, while conveniently overlooking the fact that the typical user is generally not going to give the same name to multiple files of different types by accident, let alone on purpose! So barring this rather unlikely scenario, the current implementation just works! Far better than OS 9 IMHO where I couldn't change what application opened a file without saving it in that other application or utilizing 3rd party tools. (And yes I know, application binding is a separate issue from file metadata ... but one must admit that they are definitely related).

The bottom line for me is that in OS X I simply don't have any extensions/metatdata related issues. I don't find myself in a conundrum because the OS will allow me to give multiple files of different types the same name in the same folder ... because I have never come across a good reason to do that.

Over on Arstechnica I asked you the following ....

"So I have "95%" control over the file name and great cross platform compatibility in OS X instead of 100% control over the file name and very poor cross platform compatibility in OS 9. Maybe there is a better way, but in the meantime I'll take the "95%" because that "5%" has little to no impact on my day-to-day use of OS X! My question to you is ... all theory and hypothetical situations aside ... does the current implementation negatively impact your daily use of OS X in a significant manner? I mean honestly, is the sky really falling in your computing experience because of this?"

... to which you responded ...

"Everything's relative, of course. But I really do think this is a big issue in the grand scheme of things, especially in light of the ~17 years Apple spent trying to make a go of a "better" system. Dropping all that and simply tacking on file name extensions everywhere and then papering over them in the UI does not strike me as the "technological leadership and innovation" that I expect from Apple. YMMV."

Not quite a direct answer to the question, rather, more of a reiteration of your concern regarding the direction that Apple is taking as opposed to a criticism of your current user experience ... but I didn't really expect to pin you down that easily! ;)

OAW

Developer

Sep 26, 2002, 04:49 PM

OAW, the metadata issue is not about filename extensions primarily.

It is NOT about filename extensions alone!!

JCS

Sep 26, 2002, 05:17 PM

the current implementation is quite functional and very usable on a practical basis, and is much better than the Windows implementation.

"Better than the current implementation in Windows" is damning with faint praise in this situation, IMO :) And yes, it is "usable", but I think it could be better, which is the point of the proposal.

Quite frankly, I believe that the most ardent opponents of the current implementation are coming from an "It's the principle of the thing!" mentality. That is, they come up with contrived examples

The "principles" do not exist in a vacuum. A better system would not only make current interactions more robust, understandable, and direct, it would also enable many new interactions that are not possible at all with the current system.

The way the BeOS Finder-like app ("Tracker", IIRC) could display MP3 files in list view windows with columns for "Song title", "Album", "Artist", and so on, is only the tip of the iceberg. Support for arbitrarily extensible metadata is required to reap these benefits.

all theory and hypothetical situations aside ... does the current implementation negatively impact your daily use of OS X in a significant manner?

Define "significant" :) Like I said in the Ars thread, users can get used to anything, especially geeky users. My concern is with the overall direction. MS is currently working on moving away from its legacy file metadata system and towards a more database-like approach, full of rich, extensible metadata. Apple, OTOH, is headed in the other direction, moving to a system where the only storage location for file type is in the file name, for example. Not only has Apple ceded leadership in this area to MS, it also appears to be losing ground with its metadata storage system, while MS and others race forwards.

JCS

Sep 26, 2002, 05:19 PM

[oops, double-post]

Targon

Sep 26, 2002, 05:46 PM

Recently i have bumped into another problem with this file extension issue that is a cause for my concern.

Recently, for some stupid reason Apple have decided that screen shots be captured as ".PDF" image files. Before OS X 10.2, I have NEVER seeen on the web a picture/image in ".PDF" .....NEVER so why now? Anyways, in the past i have always associated ".PDF" files aka Portable Document Files eg manuals, read me's etc with Adobe Acrobat Reader.
All my image files have always been accosiated with GraphicConverter. I set this with the "Always open this file extension with ..... whatever app"

Now im stuck in the position where these new ".PDF" image files are getting opened up by Acrobat Reader not GraphicConvertor but if i was to reverse the situation the GraphicConvertor can't open the text variety of ".PDF".

This i feel is a **** up on a grand scale. I feel this is relevent (correct me if you feel im wrong) since in Mac OS 9x due to the file type/creator meta data i could have Acrobat Reader open the ".PDF" text variety of files and have GraphicConverter open up the ".PDF" image variety of the files without issue since it isnt dependent on File Extensions...the crux of this situation.

I have also noticed more dependency on file extensions in OS X 10.2 that is annoying. Downloading ".dmg" files with the same file name eg nightly Chimera builds to the same location places a "1" suffix at the end of the file extension so it looks like this "chimera.dmg1" when this happens the file gets a generic icon and will not be post proccesed with Disk Copy because the system doesnt know what kind of file it is. Sure the ".gz" file is post proccesed with stuffit but the file goes no further an remains on the desktop and is unable to be used until the file extension has the "1" removed...at least on my system this is how thing are behaving.

This is exactly the ****up Windows has been long known for and i personally feel this is an unexceptable half assed method that should really be redesigned to avoid the situation above.

Im sure there are more instances which i have yet to discover but i think the file extension idea should be used as a last ditch effort in the failings of all other efforts to resolve a files true identity.

JLL

Sep 26, 2002, 05:54 PM

Originally posted by Targon:
I have also noticed more dependency on file extensions in OS X 10.2 that is annoying. Downloading ".dmg" files with the same file name eg nightly Chimera builds to the same location places a "1" suffix at the end of the file extension so it looks like this "chimera.dmg1" when this happens the file gets a generic icon and will not be post proccesed with Disk Copy because the system doesnt know what kind of file it is.

?? On my Mac they are named Chimera.dmg and Chimera.1.dmg

OAW

Sep 26, 2002, 06:05 PM

Originally posted by JCS:

"Better than the current implementation in Windows" is damning with faint praise in this situation, IMO :)

Touche! :)

Originally posted by JCS:

And yes, it is "usable", but I think it could be better, which is the point of the proposal.

Agreed. There is always room for improvement!

Originally posted by JCS:

The "principles" do not exist in a vacuum. A better system would not only make current interactions more robust, understandable, and direct, it would also enable many new interactions that are not possible at all with the current system.

The way the BeOS Finder-like app ("Tracker", IIRC) could display MP3 files in list view windows with columns for "Song title", "Album", "Artist", and so on, is only the tip of the iceberg. Support for arbitrarily extensible metadata is required to reap these benefits.

Agreed. This sort functionality would be ideal! Having said that, IMO I believe Apple is doing this by encouraging the use of specific iApps to organize and display various types of files. iTunes for music files, iPhoto for images, iMovie for movies, etc. .... as opposed to engineering a system where the Finder tries to be "jack of all trades".

Originally posted by JCS:

Define "significant" :) Like I said in the Ars thread, users can get used to anything, especially geeky users. My concern is with the overall direction.

By "significant", I mean does it have any negative impact on your day to day user experience? Is it something that is a constant annoyance? Or do you only think about it when contemplating how the situation could be handled even better?

For me, I never even think about extensions/metadata outside of these sorts of discussions, because the OS X implemenation is so unobtrusive. I found OS 9 to be much more of a hassle in this area, because it refused to let me work the way that I wanted to work. OS X is much better for me on a practical basis, despite the fact that it uses what could be considered a less "elegant" metadata approach.

OAW

Developer

Sep 26, 2002, 06:21 PM

Originally posted by OAW:
I believe Apple is doing this by encouraging the use of specific iApps to organize and display various types of files. iTunes for music files, iPhoto for images, iMovie for movies, etc. .... as opposed to engineering a system where the Finder tries to be "jack of all trades".Good, but not everybody's needs can be fulfilled by Apple's iApps. And some people need to work on different types of files (on the same project), that still could share the same meta data (project name, stage, customer, author...)

The Finder doesn't need to be a "jack of all trades" *), it just needs to allow arbitrary meta data categories. If it can handle stuff like ID3 tags and EXIF data by default - even better.

-
*) whatever that means

Targon

Sep 26, 2002, 06:25 PM

Originally posted by JLL:

?? On my Mac they are named Chimera.dmg and Chimera.1.dmg

No.............. as i wrote : Chimera.dmg and Chimera.dmg1 for a second instance.

Mac The Fork

Sep 26, 2002, 06:32 PM

By "significant", I mean does it have any negative impact on your day to day user experience? Is it something that is a constant annoyance? Or do you only think about it when contemplating how the situation could be handled even better?

I think the problem is that Microsoft is a moving target. It makes sense to be compatible with filename extensions, but it doesn't make sense to rest on the assumption that they will be around forever. Apple needs to prepare for a change now, or face losing sales to Windows once it catches up (soon). Though Apple doesn't have the R&D of Microsoft, they do have the flexibility to handle things better now, and they should take advantage of that. Otherwise, what's the point?

Brass

Sep 26, 2002, 06:41 PM

Originally posted by OAW:
By "significant", I mean does it have any negative impact on your day to day user experience? Is it something that is a constant annoyance? Or do you only think about it when contemplating how the situation could be handled even better?

YES! Quite significant. Eg, only YESTERDAY, I installed a new version of Mozilla on a client's Mac OS X 10.2.1 machine. Previously, the older version had been installed with just the application, alone. To install this newer version, I dragged the folder from the disk image to the /Applications folder.

When I then opened the /Applications folder, I was confronted with two identical file names (apparently), because one actually had a hidden extension of ".app" and they could co-exist. I was a bit confused as to how this happened at first, until I remembered, "that's right... Apple has screwed up how files are names, and hidden parts of the names from us, EVEN WHEN WE TELL THE OS TO SHOW ALL FILENAME EXTENSTIONS!!!

This is not the first time I've had this happen, and at least this time it was obvious (by the icons) that one of the files was a folder and the other was a file (although the other one was actually a folder too, but it just looks like a file... hmmm... does that help? :)

I'd also had several occaisions of files having two file extensions (eg, "filename.jpg.gif" with the second extension being hidden, and getting very confused about which type of file it was.

This kind of thing is totoally unacceptable in a modern operating system.

Surely we'd be better of with the old filetype and creator codes if we only had access to change them built into the OS?

Then have some API to convert between those and filename extensions when sending things by email/ftp/whatever (with some system preference to choose how and when it is done). Media4's MacDrive for Windows does this transalation between filetype/creator codes and filename extensions VERY well indeed and it is completely transparent to the user, once you've set up your preferences for it. Apple could learn a lot from these types of things.

OS X should definitely still be able to recognise a file's type from it's filename extention (because there are so many files made that way coming from Windows users and windows machines) but should ONLY use that information if the file does not have a valid creator/type code (or whatever the new equivalent metadata might be).

JCS

Sep 26, 2002, 06:42 PM

This sort functionality would be ideal! Having said that, IMO I believe Apple is doing this by encouraging the use of specific iApps to organize and display various types of files. iTunes for music files, iPhoto for images, iMovie for movies, etc. .... as opposed to engineering a system where the Finder tries to be "jack of all trades".

This is absolutely the wrong approach! And I suspect Apple knows this, but Apple is forced to "reinvent the wheel" in each iTunes-like app because the OS doesn't provided the services that apps like this need!

The OS is supposed to provide services to applications, and I have a hard time thinking of any application that couldn't benefit from rich metadata services, were they provided by the OS.

Every time I see yet another application roll its own metadata database system from scratch, I cringe. The OS should provide the infrastructure for metadata. Imagine how much better the apps you use on a daily basis (e.g. Mail, the Finder, even iTunes and iPhoto) could be if the metadata-powered viewing, searching, and organizing abilities demonstrated in iTunes came "for free" from the OS for an app that wanted to use them.

By "significant", I mean does it have any negative impact on your day to day user experience? Is it something that is a constant annoyance? Or do you only think about it when contemplating how the situation could be handled even better?

Well, it annoys me that things are added to my file names without my consent or control; it annoys me that I always have to be conscious of the "actual" file name, which may or may not be the "displayed" file name (this becomes important when FTPing files to a web server, for example, since links must point to the "actual" file name...and I find turning off file name extension hiding entirely is even worse, from an aesthetic perspective); it annoys me that renaming a file can sometimes be a "harmful" operation.

So yes, I'd classify it as a "constant annoyance" to me personally, but that's the really the point. The solution is not to "stop doing things that annoy me personally." The solution is to fix the root of the problem(s) and not only fix the annoyances, but also enable all the great new features and services that "the world's most advanced operating system" should be providing.

Amorph

Sep 26, 2002, 07:02 PM

Originally posted by JCS:

Every time I see yet another application roll its own metadata database system from scratch, I cringe. The OS should provide the infrastructure for metadata. Imagine how much better the apps you use on a daily basis (e.g. Mail, the Finder, even iTunes and iPhoto) could be if the metadata-powered viewing, searching, and organizing abilities demonstrated in iTunes came "for free" from the OS for an app that wanted to use them.

Optimist that I am, I actually consider this (along with the more or less stagnant Finder) evidence that Apple has plans to implement some form of robust metadata in a forthcoming release. The iApps cry out for rich file metadata.

Well, it annoys me that things are added to my file names without my consent or control; it annoys me that I always have to be conscious of the "actual" file name, which may or may not be the "displayed" file name (this becomes important when FTPing files to a web server, for example, since links must point to the "actual" file name...and I find turning off file name extension hiding entirely is even worse, from an aesthetic perspective); it annoys me that renaming a file can sometimes be a "harmful" operation.

It took me a little getting used to (since I work in Windows 8 hours a day, it didn't take much...). I turned off extension hiding, which even in Apple's enlightened implementation is an abomination - why would you voluntarily hide metadata? - and got used to keeping the extensions around.

It actually helped me, once. I had a recalcitrant (possibly corrupted) file with no suffix at all to deal with, so I changed the suffix to .txt and opened it in BBEdit. :) Now, granted, I could have found a less cumbersome way to do that (I'm still in 10.1, though, so the options are a bit thin), but it was helpful nevertheless.

So yes, I'd classify it as a "constant annoyance" to me personally, but that's the really the point. The solution is not to "stop doing things that annoy me personally." The solution is to fix the root of the problem(s) and not only fix the annoyances, but also enable all the great new features and services that "the world's most advanced operating system" should be providing.

On the other hand, if you're moving from a binary metadata system like HFS to a more portable variety (MIME and/or XML-based), you first have to clear out the old system. You also have to clear out Mac OS 9, which can't grok anything but HFS/HFS+. So guess what Apple's doing? ;)

But, like I said, I'm an optimist.

JCS

Sep 26, 2002, 07:51 PM

if you're moving from a binary metadata system like HFS to a more portable variety (MIME and/or XML-based), you first have to clear out the old system.

No you don't, since the new system will be extensible and can therefore support the old system easily during the transition. (Also, what is a "binary" metadata system? A metadata system with only two values? ;-)

You also have to clear out Mac OS 9, which can't grok anything but HFS/HFS+.

That's actually an argument for keeping that information around until Mac OS 9 is gone. Yes, of course, Mac OS 9 will go away eventually, but until then applications should make sure the files they create can be read by the millions of Mac OS 9 systems still out there.

So guess what Apple's doing?

Beats me... :)

Developer

Sep 26, 2002, 08:14 PM

Do we really need metadata support in the file system? Let's see:

All files have metadata like names, creation and modification dates, permissions etc.
For the metadata not natively supported on the file system, the OS writes them into a .DS_Store database.

mp3s contain ID3 tags. For metadata not supported by ID3 tags (either because the mp3 uses an older version, or it's iTunes specific like ratings) iTunes writes the metadata into a separate database.

Images contain EXIF data which iPhoto can handle. For data specific to iPhoto (labels, thumbnails) iPhoto writes that into a separate database.

Curator does the same, but with a separate proprietary database.

As does Photoshop that writes the metadata into a .md0 database for metadata and a .tb0 for thumbnails.

Conclusion:
a) most decent applications require metadata as above examples prove.
b) proprietary, incompatible metadata databases that easily break if files are moved, renamed, or edited by other applications need to go away, and the metadata support must move into the file system.

Brass

Sep 26, 2002, 08:34 PM

Originally posted by Developer:

Conclusion:
a) most decent applications require metadata as above examples prove.
b) proprietary, incompatible metadata databases that easily break if files are moved, renamed, or edited by other applications need to go away, and the metadata support must move into the file system.

And BeOS / BFS was the only OS / FS that really did this well. I sure hope that Apple come up with something at least as good as whet the BeOS used. It has such an incredibly versatile and extensible metadata system.

clarkgoble

Sep 26, 2002, 08:38 PM

Once again to restate what has been said many times, Apple hired the BeOS filesystem guy to do their new file system. If you've read his book on file systems you know how well he's thought these things out. (That book is without a doubt not only one the best books on file systems I've read but one of the easiest and clearest writings on a fairly complex topic I've seen)

I suspect that OS XI or whatever it will be called will have a pretty amazing and efficient file system. If Apple can deliver that plus some good hardware to compete with Intel, then Linux may find itself in trouble for everything but servers.

JCS

Sep 26, 2002, 09:33 PM

Apple hired the BeOS filesystem guy...

This is true.

...to do their new file system.

This is speculation, isn't it? :)

Amorph

Sep 26, 2002, 10:14 PM

Originally posted by JCS:

No you don't, since the new system will be extensible and can therefore support the old system easily during the transition. (Also, what is a "binary" metadata system? A metadata system with only two values? ;-)

Yeah. TYPE and CREATOR. ;)

No, a system that stores metadata in a binary format. So that it's inaccessible to the rest of the world.

The original system might be able to be configured to support the limited and primitive (but largely effective) implementation supported by OS 9, but that will simply encourage it to stick around. I think it's pretty clear that Apple doesn't want it to stick around.

That's actually an argument for keeping that information around until Mac OS 9 is gone. Yes, of course, Mac OS 9 will go away eventually, but until then applications should make sure the files they create can be read by the millions of Mac OS 9 systems still out there.

Mac OS 9 is gone next year, as far as Apple is concerned. The millions of OS 9 systems have a perfectly nice subsystem for associating extensions to file types, so baseline compatibility from X to 9 is not a problem. It might not be what you'd like, but I don't see Apple supporting OS 9 style metadata no matter what solution they finally settle on.

Should Apple decide to do so, Classic can easily be fooled into thinking that it has type and creator codes to work with, since it uses OS X's filesystem. Fooling OS 9 would be another matter, which is one reason why I think Apple is keen to kill it. Hardware isn't the only thing Mac OS is inflexible about.

eno

Sep 26, 2002, 10:41 PM

Originally posted by JCS:
Well, it looks like Apple closed the bug filed as part of the Mac OS X metadata proposal. The close message? "Closed/Behaves correctly." *sigh*

For more information:

http://homepage.mac.com/jcs/.Public/metadata.html
Give it a rest, John, and stick to doing what you do best (writing Mac OS X REVIEWS).

One would think that this would be enough to make you call it quits, but it seems no...

I am trying very hard to be amused by all this rather than bored, but the truth is it's starting to get quite annoying to hear your constant yapping about this.

Brass

Sep 26, 2002, 11:02 PM

Originally posted by eno:

Give it a rest, John, and stick to doing what you do best (writing Mac OS X REVIEWS).

One would think that this would be enough to make you call it quits, but it seems no...

I am trying very hard to be amused by all this rather than bored, but the truth is it's starting to get quite annoying to hear your constant yapping about this.

Sometimes "constant yapping" is the only way to get a message across. Especially when you're trying to get the message across to a group diss-interested in their own clients as Apple.

If you tired of listening then dont' listen. But those of us who are unhappy with Apple's decisions are entitled to air our concerns.

cpt kangarooski

Sep 26, 2002, 11:23 PM

I concur. Apple's dropped the ball. Accepting it isn't going to help matters any. I'm fully behind John.

Big Mac

Sep 26, 2002, 11:34 PM

The only thing I'm prepared to say about metadata is the following:

File name extensions should definitely be used as a last resort; they are not a replacement for types and creators. The fact that file name extensions currently work "okay" isn't good enough for me. Those users who are prepared to forgo proper metadata support just don't get it.

biscuit

Sep 27, 2002, 04:47 AM

I, like Amorph, am an optimist. I find it hard to believe that Apple isn't working on something new here. I suspect the reason we haven't seen it yet is because it is/was too big a job to be doing whilst trying to get OS X out the door. So HFS sticks around for now (for Classic etc.) but Windows compatibility is improved by supporting File extensions. The end result is functional but maybe not as elegant as Apple might have liked, but that doesn't matter because theres something new in the pipeline anyway.

I think this BeOS guy has to be working on either the File System or the Finder. As far as I can tell thats where his skills lie.

Maybe I'm a little over-optimistic, but I truely believe things will change. Give it a little time and Apple will have picked up that ball and will be running ahead of the field again.

Of course, active discussion and feedback never hurt...

biscuit

sadie

Sep 27, 2002, 07:14 AM

I'm with John as well. I do hope the optomists are right, and Apple is working on this (long and difficult) issue in one of their labs somewhere. But until I know, until they've committed to this, until I know whether my platform is going to stay the world leader or just drop into computing history, I'm going to keep pestering.

JCS

Sep 27, 2002, 10:09 AM

I am trying very hard to be amused by all this rather than bored, but the truth is it's starting to get quite annoying to hear your constant yapping about this.

Is someone coming into your house and talking to you about this issue against your will? Or is there some sort of virus on your computer that forces your browser to automatically open all threads I start about metadata? Hmmm... ;)

Amorph

Sep 27, 2002, 11:45 AM

Originally posted by biscuit:
I, like Amorph, am an optimist. I find it hard to believe that Apple isn't working on something new here.

[...]

Of course, active discussion and feedback never hurt...

Certainly not. Which is why, if you go to JCS' page about this (linked at the top of the thread), you'll see my John Hancock among the "sample signatures." :)

stew

Sep 27, 2002, 12:07 PM

Give it up, John. You're a misfit. A rebel. A troublemaker. You see things differently.
Apple doesn't want people like you.

;)

OAW

Sep 27, 2002, 01:22 PM

Just for clarity ...

In case anyone got the impression that I was advocating the current implementation as the "best" approach, then let me state clearly that I agree with John's proposal. However, let me also be clear in stating that for me the current approach is much better than the OS 9 approach. Extensions/metadata and all that just simply isn't an issue in my typical computing experience. Of course, YMMV.

The bottom line for me is that if Apple implemented something like John's proposal ... I would be all for it. But in the meantime, I'll take the OS X implementation over the OS 9 implementation anyday. And I daresay there are a lot more who agree with me than some would care to admit.

OAW

Sven G

Sep 27, 2002, 02:16 PM

Originally posted by stew:
Give it up, John. You're a misfit. A rebel. A troublemaker. You see things differently.
Apple doesn't want people like you.

;)

Regrettably, that (the last line) seems to be the current trend at Apple, today: if only they could Think Different�...!

But - probably! - there's some hope with the former BeOS and Mozilla programmers that Steve-O has hired, recently... :cool:

macmike42

Sep 27, 2002, 02:58 PM

1) OS X 10.2.1 currently prefers file types over extensions. Proof:

http://users.rcn.com/booth7/images/forum-posts/metadata.png

2) Apple made (and continues making) a mistake in choosing to leave "Always show file extensions" off by default.

3) Apple has not made a mistake in mandating that file extensions are the only required way to identify file types, since it is the only method that is supported by every file system the OS can use (only HFS(+) supports file types and creators natively, the rest require dotfiles scattered everywhere, and network file systems are too slow to use the magic number method).

4) Any app that automatically changes a file's extension when a file with the same name exists is doing the wrong thing.