Differences between DMG and various Zip-like formats?

Question

For my everyday work, I have a few DMG files that I keep on cloud storage. At the beginning of the day, I download my DMGs, convert them from Compressed to Read/Write using Disk Utility (OSX). At the end of the day, I convert them back to Compressed and upload.

It might sound cumbersome, but I sort of like it.

My question is, what if I ditched that workflow for something where I just download a Zip file (or something similar), unzip it, modify my files, zip it back up, and reupload it? Would I lose my file metadata or anything else useful compared to what I get by using DMGs?

Are there any other options you could suggest that make it easy to download ONE compressed file, modify what's inside it, and re-upload it?

Please don't suggest using Dropbox, Gdrive, etc.

Solution

DMG files are not zipped files, as much as they are images. They are closer to an .iso than a .zip in that they are disk images which are mountable and the contents can be compressed.

A DMG therefor must also contain block data, along with the regular file attributes like Meta data and the actual data of the file.

A good compression / zip like 7zip should be able to make smaller files (Maybe faster), and keep the data you need without stuff like block data for whatever file system your DMGs use (HFS, UDF and FAT are some of the options).