Possible to peek/poke to access RAM directly ?

Happy to hear that. How to find such a free area ? What address should I look for ? All I know is that RAM starts at 0x20000000. Should I start to write there until something bad happens ?

The Uint8Array header seem to be 3 blocks long, even for short arrays. But apart from that, its store bytes 1:1 like you said. Thanks a lot, I will use that.

>var b=new Uint8Array(16);E.getSizeOf(b);
=4
>var b=new Uint8Array(400);E.getSizeOf(b); // 28 = 3+400/16
=28
>var b=new Uint8Array(1024);E.getSizeOf(b); // 67 = 3+1024/16
=67
>var b=new Uint8Array(10000);E.getSizeOf(b); // 628 = 3+100000/16
=628