Time Capsule as external hard-drive, as back-up drive with Time Machine

Question

Two questions today:
I understand that I can use the Time Capsule as an external hard-drive while using it as my back-up location, using Time Machine. It has been suggested that to do this, it is best to partition the Time Capsule to prevent the TM program from confusing the files it manages, the data files from the backed-up files. (I hope I got that right.) I believe I read in this forum that one can partition the TC after the fact, and not destroy any data on it. Is this possible? A clerk at the Apple Store in San Francisco told me that I would want to partition, but that it would require that I erase the TC. Which to believe?
Secondly, how does TM create the back-ups? I have used SuperDuper and appreciated the difference in how (and what) it backs up. My example: my first back-up involved having an 80gb external drive attached to my computer and TM backed up both my HD and the External Drive. I then turned off the TM. Today I turned it on and allowed it to back-up every hour as it is designed to do, but without the 80gb External drive attached. When I checked the newer back-ups, they all showed the original configuration of HD and 80gb external drive.
So for it's incremental back-ups, does TM back up new files and updated files without deleting missing files? Is it an additive process? Or does it at some point delete missing files from it's most recent back-up? Or since it recognized that it was backing-up two different drives, it will always keep them separate, maintaining one (80gb External drive), even as it backs-up and changes the other (the HD)?
O.K. a third request. Has anyone published a manual on TM and/or TC with this level of understanding so we can make the most of it's 1 TB storage capacity?
Thanks in advance, LeRoy

Answer 1

LeroyHoward wrote: So, does this mean that TM never deletes a file?
It will when it starts to run out of space and it should likely be the oldest deleted files first.
As I understand it, as long as I have a multi-linked file icon on the TM, I have the original data. And everytime the TM backs-up, it recreates every multi-linked file icon on the previous back-up. Right? So, if you delete a file by mistake, you can go back and find it. But I see a contradiction here. If you delete it on your desktop, shouldn't it be deleted from the back-up of that desktop? We expect it to be on earlier back-ups, but not the most recent one right? So, eventually as the TM fills up and begins deleting earlier back-ups, that data will be lost.
The newest timeline will not point/display the deleted file(s), but it still exists on the backup until the backup drive fills up and needs to erase deleted data.
I'm trying to understand this aspect of the TC and TM, because we want to use it as both an external HD and as one of our back-ups. Any light you can shed on this will be greatly appreciated.
Thanks, LeRoy
Read Glenn's response to dedicating TC to TM backup and the difficulty in partitioning the TC HDD.
Glenn Carter wrote:
However, this is not an option for Time Capsule users as there is not an easy way of partitioning the Time Capsules’ internal had disk without elaborate effort. In this case, use the Time Capsule hard disk solely for Time Machine backups. Then attach an additional hard disk to the Time Capsules USB port and store additional files there. This added disk will still be available to all Macs that can access the Time Capsule.
This works to share the files on the USB HDD attached to TC, but if you want this drive backed up by TM (and this drive is formatted HFS+), then it needs to remain plugged into the Mac directly for TM to back it up.