What you lack in tact is made up for in simplistic wisdom. Wonderful. Now are they taking up some of the 16gb of storage space or are they on the simm. Not interested in pulling a simm card to find out......
Text messages and iMessages are stored in an
SQLite database deep in the filesystem of the iPhone. So yes, they take up storage space on your phone.
Voicemails are kept on AT&T's voicemail servers for bout 2 weeks, but they are also downloaded to your phone's filesystem, where they can stay as long you want until you delete them. They take up storage space, too.
In the grand scheme of things, you'd have to have a LOT of text messages (like, in the millions) before you'd start seeing them make a real dent in terms of storage. Assuming 160 characters per message, 100,000 text messages would probably take up 20 to 25MB or so, if you factor in sender/receiver info, timestamps, and other overhead. On a 16GB filesystem - let alone a 32 or 64GB filesystem - 25MB can be fairly easily missed without being noticed much. Though, photos and videos will obviously take up more space than that.
Voicemails and sound files will take up a bit more space though. Voicemail messages are stored in
AMR format, and an average 60-second voicemail message will be in the neighborhood of 700 to 750 kilobytes in size.
There's no chance really, of these things getting stored on your SIM. That could've been viable in the age of dumbphones, when storing only a couple dozen text messages was reasonable. But current SIM cards have maybe 64MB of storage space... not nearly enough to store most people's contacts, texts AND VM messages from a typical smartphone user that expects to keeps years worth of stuff around.
