Android Emulator sdcard Read-only to be Writable

For an Android emulator to make a writable sdcard, we need to use "SD Card Emulation".

To do it on a host computer where Eclipse ADT runs on

     mksdcard

For example:   

     mksdcard 1024M sdcard1.iso

then in Eclipse put the file path in Android Virtual Device Manager ->Edit ->SD Card->File. or
  
     emulator -sdcard