Back-ups with and without Time Machine + G -MINI

Question

I've got a problem with my new G - MINI 500GB running on an iMac intel 10.5.1/ 230GB. I hope someone can help me with this.
Overview of problem: I need more hard disc space and opted for an external drive. I would have got a G _Tech Q 500 gb drive but there weren't any immediately available so got the G -MINI 500. Basically this is for video and large audio files. Anyway, I plugged the new MINI in and it pretty much set itself up. Time Machine offered to do a back up of my whole system and contents, I clicked 'accept' and excluding a few items in the options pane in TM it came to around 210 GBs now on the MINI. As I need to take the Mac in for servicing a defective LCD I thought a back up of the system a good idea. I added a few other video files in a separate folder on the MINI. I then thought that was way too much- I will need more than the remaining 245 GBs for future stuff. So I wanted to get some more space back and thinking that it would work pretty much like the Mac's own hard disc and Flash USB drives I just tried to send some files from the back-up folder on the MIni to the trash in the dock. I got a message saying I couldn't trash any files included in a back-up! Kinda locked. I tried trashing one of the video files that wasn't in the system TM back-up folder and it did go to the trash but then I checked the available memory on the MINI hadn't reflected change: the size of that file wasn't added to the 'available memory'. Buff, problem.
Anyway, I then decided to trash the whole back-up folder and everything else. All went in the trash can in the dock but again, despite expecting the Mini's space to have been freed up, like any hard drive or other storage device, it hadn't been. It still counted 210 GB used up. To make sure I emptied the trash as well but again with no result.
I couldn't access the trashed files in any way now but the Mini was obviously counting them. What's going on?
So then used DisK Utility to check the MINI, same result, and then completely exasperated I just went ahead and partitioned it, that seeming the best option at the time. I got the space back but lost about 230 MG in the process. Annoying all in all. Now, I didn't want a Drive that you can't eliminate files from without having to erase the whole bl**dy disk! This seems to be the only way to get space back from the MINI's drive but it seems ludicrous. What am I doing wrong, what don't I know?
A related question is what's the difference between 'erasing' a disk and 'partitioning' one (in Disk Utility). I can't work this one out. The important question is whether there is a way to delete items from the Mini in order to get back the space they occupy. If not I should have bought something else. I thought G -Tech was supposed to be top end, it is faster than USB I'll give it that for now.
Thanks in advance for any replies.
Oh and I'm posting this here because there is nothing in G Tech support about this and the post I sent to the G Tech forum goes unanswered after 2 days already - it seems like a simple question that someone should know the answer to. I want to know if I should just simply copy files to the mini and not bother with system files unless I really want to make a back up. A final question would also be: what exact folders are needed to make just a simple system back up but without all the clutter that you could reinstall from the discs anyway?
Thanks!
Message was edited by: Paul Quemades

Answer 1

If you just want to drag a few files around how about create a folder on the external drive. I know some say you shouldn't do this, but TM will still work even if there is another folder on the same volume you use for backing up with TM. In that folder you can drag whatever into it, just as you are able to do on any flash drive.
But let's revisit how TM works. I don't understand the detailed operation of TM but once it establishes the initial large copy of your Operating System, subsequent small changes are linked back to the big one, so when in the Time Machine window with all of the different backups over the past days or weeks, clicking on any one of them will show you what appears to be the same thing - the contents of your hard disk. In amongst that will be the small changes or added files.
To save it recreating by and large the same appearance of your hard disk each time it reuses the initial copy and just adds any changes. It does this by associating any newly changed or newly added file to the base copy, by using links. It is like creating a context for the file, so TM is making file X linked to folder Y which is part of application Z. If we want that file back using TM, it will know that file X has certain associations and it will put it back where it got it from.
When we drag that same file to another location, it is just that file in isolation. It has no context. The only association it has, is what we remember about it, "that photo was taken at Lucy's wedding" for instance. TM or the computer for that matter doesn't know who Lucy is, or even that she is a human being.
So in our flesh and blood reality, we see files as objects that have meaning to us, but to the computer it is all just data that has a place and a function. Time machine is a kind of illusion. It is also a Place machine by replacing files in previous places.
You say to use TM to just store "things like personal documents, music, video and other such stuff, unrelated to system back ups, seems such a fussy and tedious way to do it,..." I agree, but TM has the advantage of being able to restore any file no matter how obscure, or even restore your whole OS if you needed to. You can always retrieve any document or song or photo from TM by going into TM and having it restore that document. Not you dragging and dropping but letting it do it. The other advantage of TM is that it will keep variations of the same file as it is changed, such as various drafts as they are edited.
Maybe a more suitable backup application for you may be SuperDuper, where you can greatly control what is backs up. The disadvantage of superDuper is it won't keep older versions of something, rather make a fresh copy of that folder each time you use it.
So you have a few options, but I think if you can get used to opening TM and locating the files that it automatically saved, and telling it to restore those back to your hard drive, it may well serve your needs.
roam