Storing photos in iCloud

Photo stream only uploads photos, not videos, and it only maintains 1000 photos for 30 days. It's meant for temporary storage, allowing you time to download them to your other devices, not for permanent backups. The only way to permanently store your photos is to import them to your computer (see http://support.apple.com/kb/HT4083) or subscribe a different cloud service which is designed for permanent storage (such as Dropbox)

This gives you an overview of iCloud: http://www.apple.com/icloud/features/. To answer some of your questions, iCloud does keep a permanent backup of your device, although I believe, like backing up to iTunes, it overwrites/updates your backup each time you back up your device rather than keeping multiple historical backups. You have some control over what is included in the backup by going to Settings>iCloud>Storage & Backup>Manage Storage>tap your backup then look under Backup Options in the window that opens. Space permitting, you can back up multiple iOS devices to the same iCloud account if you want, however, you can also create a separate iCloud account for each device (which will require using a separate Apple ID for each). However, with separate accounts, you won't have access to the same Photo Stream photos. You may feel that all these are significant limitations, but remember that it is a free service. There are many other cloud services available which offer more if you're willing to pay a subscription for them.

You can't "mount" an iOS device to your computer as they don't operate in "disk mode" like iPods do. You don't have access to the file structure of an iOS device unless you use 3rd party software such as PhoneView (mac) or Touch Copy (pc or mac). On your last question, both iCloud and iTunes will identify each of your iOS devices as unique devices, which allows them to be backed up separately.

You're welcome. Regarding your syncing issue, iOS devices are designed to only be synced with a single iTunes library. When you sync with a new iTunes library all iTunes content (apps, music, videos, books, etc.) will be erased from your device and replaced with the content in the iTunes library you are syncing with. This isn't an issue if the iTunes library you are syncing with already contains the content on your phone as it will simply be synced back to your phone. So to sync with a new library you need to transfer the iTunes media from your phone to the library prior to syncing. This guide provides the steps for doing this: https://discussions.apple.com/docs/DOC-3141, including disabling automatic syncing, authorizing your computer for the Apple IDs used to purchase the content on your phone (so it will transfer to your library), transferring purchases from your phone to your library, backing up your phone with iTunes, and syncing. If you are also syncing your calendar and/or contacts with your computer using iTunes you also have to perform step #2 in this guide to prevent them from being overwritten by syncing with an empty calendar or contacts client on your computer. (If you aren't, you can skip this step as long as you make sure you don't select to sync these on the Info tab of your sync settings prior to syncing your phone in step 9.) The only issue you will run into is that iTunes will not transfer photos synced to your phone from your computer (i.e., non-camera roll photos) or music that was not purchased from the iTunes store. This content must be transferred to your computer using other means as discussed in the guide. If you only need to transfer non-camera roll photos you can accomplish this with an app like PhotoSync. (If your non-iTunes store music is only on your phone you will need to use a program such as Touch Copy.) Failure to do so will result in this content being erased from your phone. Once you go through this process you will be able to sync with this iTunes library without getting the warning that it will replace the contents on your phone. If, however, you attempt to then sync with a different computer/iTunes library you will get this warning again and have to repeat this whole process to resolve it.

Hope this helps.

iTunes syncing is two-way so changes made on one iOS device will be reflected on othe iOS devices so long as they are all sycing to the same iTunes library on the same computer. An example would be if you changed your contacts and calendar on your phone, then synced, these changes would be updated in Address Book & iCal (and vice versa if you made changes on your mac). If you then synced and iPad with the same iTunes library, these changes would update the calendar and contacts on your iPad (and any changes made on your iPad would similarly make the corresponding changes on your mac). The issue that I think you may be facing in your situation is that you also want these changes to be reflected across multiple computers, not just the one computer you sync with. This is what iCloud was designed for; synchronizing changes across devices, including multiple computers. (As you may know, this was a paradigm shift for Apple, in which their vision changed from seeing a single computer as being the digital hub around which all portable devices synced, to seeing iCloud as the digital hub and the computer as just another device.) Unfortunately, as you know, to fully implement this requires OS X Lion, which is not compatible with some older macs.

In my situation I have two computers (pc and mac) and multiple iOS devices all syncing with iCloud so this operates flawlessly. Yet I still have to sync my iOS devices with only a single computer/iTunes library that contains all my iTunes media. With iCloud, this doesn't pose any limitation. Changes to Calendars, contacts, bookmarks, etc on any device are reflected on all other devices. And if you have Photo Stream enabled, any photos you take will also automatically download to iPhoto for permanent archiving.

You're welcome. Glad I could help.

I find this to be a very good question, "What does iCloud do?" It does NOT back up music, tv, movies, and audiobooks. It claims to back up ring tones but does NOT back them all up. It backs up purchased items from iTunes but you may have to restore them manually. Basically, it is a way to save your contacts, reminders and calendars in addition to backing them up in iTunes. Be careful if you share an iCloud account as you will then also share contacts and if your account co-owner decides to delete these contacts they are gone from their phone, icloud and your phone!

I find iCloud useless really. You still have to "sync" with iTunes or you will lose data. (Oh, and "Backup & Restore" in iTunes is not really a Backup & Restore in the English sense of the words. You basically back up some settings but not data.)

Basically, there is no simple way to back up an Apple device and be certain that you can restore it to another device in the future. Living with Apple means dealing with a very clunky file manipulation system. Do not count on iCloud for help with this.

just FYI...

there is no more "ettings>iCloud>Storage & Backup>Manage Storage> "

That reply is from 4.5 years ago. iOS has changed several times since then.

Settings > iCloud > Storage > Manage Storage is the current path.