SIM Card Filesystem
SIM card is one of smartcard type use widely on telecomunication sector. As a smartchip which has operating system, CPU, RAM, it also has a filesystem. You need to read 3GPP TS 51.011 about Specification of the Subscriber Identity Module – Mobile Equipment (SIM – ME) interface.
Now I am going to share a picture of a filesystem on a working SIMCard, sorry some secret information is not revealed :). Moreover this picture is taken from commercial product Gemalto Card Admin.
For each details of those file, please read the above spec