hqx, sit, zip, dmg? I'm confused.

[bittersweet]

Hi all,
I was wondering which among the 4 I can safely trash without interfering with the program it contains.

(hqx, sit, zip -- okay, this can be safely removed after Un-Stuffing right?, and dmg).

[Kenneth]

You can't delete the DMG file because that's where the actuall image resides. As for the others, yes, after decompressing, you can throw them away.

[ginoledesma]

Like Kenneth, you can safely delete the other "compressed files" after extracting them.

If you care for a little "history," you might understand them better

You already know ZIP, as that's the most common compression format used in the PC world. In the Mac world, the Stuffit (SIT) format was the most popular.

When the Internet became more accessible to the common folk, the Stuffit format proved to be problematic when sent as an email attachment. The reason was because email servers, mostly running on Unix systems, did not understand the format. Certain Mac files have two "pars" -- the resource fork and the data fork. When these files are transmitted through the Internet over email, the resource fork is almost always lost, which means programs sent through email will no longer "run" on the target computer (if it's a Mac). Technically speaking, Unix email systems spoke "7-bit", whereas Macs spoke "8-bit". So when an 8-bit file is moved through a 7-bit system, the file becomes damaged.

To fix this, the proccess of encoding was used to "transform" an 8-bit file into a 7-bit file. The receiving computer just has to "reconvert" these into its original format. One such encoding is BinHex (hqx), short for binary hexadecimal encoding. Though most systems these days support 8-bit encoding, hqx is still around "just in case."

Other encoding format you may run into is MacBinary (.bin), which basically transforms Mac files with two parts (resource/data forks) into a single 8-bit file. The target computer has just to "separate" these two combined parts.

Starting with the late releases of Mac OS (e.g. Mac OS 8.6/9.x), disk images were becoming more common. The classic versions use the IMG extension, and these can be mounted by Disk Copy. With Mac OS X, disk images took on another format, this time ending with the .dmg extension. You can use Disk Utility (or the Finder) to "mount" these images. Stuffit Expander is still a popular chocie for people to use as a compression format, although you'll notice that Mac OS X has built-in support for ZIP (common in Unix environments).

So there you have it:
ZIP -- popular compression file format in the PC (Windows) world.
SIT -- legacy / popular compression file format in the Mac world.
HQX -- an old way to safely transfer Mac files over the Internet.
IMG -- Mac OS 9.x disk image
DMG -- Mac OS X disk image

Other formats:
UU -- Unix to Unix encoding (similar to HQX)
MIME -- E-mail encoding (similar to UU, HQX)
TAR -- Unix "tarball" compressed format
GZ -- Unix "gzip" compression format (similar to ZIP)
BZ2 -- Unix "bz2" compression format

[Edited on 7-23-2004 by ginoledesma]

[Jiru-chan]

Wow, Gino, that's a very informative post! Thanks! (Even though I'm not the original thread poster ehhehehe)

[bittersweet]

I second Jiru-chan.

You da man Gino!

[caloysam]

I agree with that. These are the things thatmake you go "hmmm...", but after reading it, the "hmmm..." would go to an "aaah!" Thanks Gino!

[bok]

Originally posted by Kenneth
You can't delete the DMG file because that's where the actuall image resides. As for the others, yes, after decompressing, you can throw them away.

You can delete this .dmg file after you've 'ejected' it. Do that only _after_ you've installed its contents to your hard drive.

[NoisyCricket]

newbie sorry. I've got a *.dmg file. Do I just click on it? Do I need special software to open it?

Thanks!

[penmanila]

yes, just click on it, it'll open up on its own. that's a disk image file--usually for installations.

[NoisyCricket]

great! thanks.

slightly-OT: Would you guys recommend Toast Titanium? Or the standard issue dvd-burning progams be fine?