smartcard (in general) or SIM card (for mobile) is like a ultra-micro-mini computer.

it has a processor and storage. This storage is very small because it serves a very basic function (like floppy -> cd -> hdd).

similar to hdd, u have different type of "partitions" for different kind of "applications"

the larger the size, the more "applications" can be fit into.

why 3G sim (it's called USIM or Universal SIM) starts from 128K because it needed a dedicated "application" for 3G functionality.


off-topic: do you know our MyKad has different functions? National ID, e-passport, drivers license, MEPS, ATM, Touch'n'Go?

all these are individual "applications" stored inside a smartcard chip.

Each application DOES NOT interfere with the others. It has it's own multi-level encryption and authorizations.

Each entity (or govt / private agencies) dictates their own security and HIGHLY proprietary. Each security level has 2 type of encrytion/decryption key: PRIVATE and PUBLIC.

for e.g. to access drivers license, u need the PUBLIC decryption key and access authorization from National Transport Dept.

To update your IC, u go to National Registration Dept. To reload TnG, u go to Touch'nGo counters

why we can "read" these info everywhere because data is retrieved ONLY (with PUBLIC DECRYPTION key). You CAN NOT write/overwrite any information into the chip without knowing the PRIVATE DECRYPTION/ENCRYPTION key.

http://en.wikipedia.org/wiki/Universal_Sub...ity_Module#USIM

http://www.justaskgemalto.com/en/communica...-and-usim-cards

Gemalto is a very huge corporation, merged between Gemplus and Axalto few years back. A LOT of smartcard/sim card/credit card uses Gemalto's chip.


Also, there will be 1MB USIM (or MegaSIM). Google it.

This post has been edited by cybpsych: Oct 11 2009, 07:38 AM

1KB settings is one thing.

the applet is another matter because it take space.

highlight this to Maxis service centre.

they should provide free fix or free sim for you.