Channel One wrote in post #19349262
You would be surprised how many apps will fail to work properly without being able to connect to the net, I don't use a phone for a camera, so that wasn't even considered.
For me phones are for text/talk and sometimes for locating which requires a internet connection.
If I need comms out in the ocean I use LMR or satellite, LMR out to 20 miles or so and sat after that.
That statement clears this up, to a point. For your particular needs, the phone is useless without a connection. I know about apps that don't work without a net connection, and I write some apps that buffer data until it can get the correct connection. However, you, in turn, would be surprised at how many apps work fine without being able to connect to the net. E-book readers work fine if you download the books first. I sow someone playing a word game during my last overseas trip a couple of weeks ago, and I don't think she bought United Airline's internet service.
You mention "...and sometimes for locating which requires a internet connection."
I'm assuming you mean location on a map, that doesn't need an internet connection at all! I routinely fly using charts stored on my phone or iPad, which has enough memory to hold the data for the world. The phone is a back-up; I don't have internet is the planes I fly. As I mentioned, the GPS in your phone has no need of the internet; that is an independent navigation system using GPS and GLONASS (well, maybe not that set of satellites for now, I haven't checked to see if the Russians scrambled their system). Phones get assistance from their towers, but phones don't need the towers to determine a position. There are any number of apps that give position data and use the compass in the phone to show which way is north. On Android phones, a section of Google maps can be loaded to be used when you are off-line. You can download marine charts you can use off-line for about $9 from the Apple store.
Channel One wrote in post #19349263A very limited computer with limited memory and slow processing.
What are you running that needs that much computing power? I doubt you are running simulations of protein structures on your phone.
Here are some uses for cell phones as computers that don't use a network:
Optofluidic Fluorescent Imaging Cytometry on a Cell Phone: https://pubs.acs.org/doi/10.1021/ac201587a
A Cell-Phone-Based Acoustofluidic Platform for Quantitative Point-of-Care Testing: https://pubs.acs.org/doi/10.1021/acsnano.9b08349
Catechol Patterned Film Enables the Enzymatic Detection of Glucose with Cell Phone Imaging: https://pubs.acs.org …021/acssuschemeng.1c04896
Reading Out Single-Molecule Digital RNA and DNA Isothermal Amplification in Nanoliter Volumes with Unmodified Camera Phones: https://pubs.acs.org/doi/10.1021/acsnano.5b07338
Increased Robustness of Single-Molecule Counting with Microfluidics, Digital Isothermal Amplification, and a Mobile Phone versus Real-Time Kinetic Measurements: https://pubs.acs.org/doi/10.1021/ac4030413
Teaching Beer’s Law and Absorption Spectrophotometry with a Smart Phone: A Substantially Simplified Protocol: https://pubs.acs.org ….1021/acs.jchemed.5b00844
