is the hex or bin which is really programed on the chip

[makouda]

I use nrfgo studio to program the hex file. but I have only 128kb of flash and the softdevice took 88kb which left less then 50kb. I have a hex file of 70kb my question is if the hex file is directley programmed to the flash or in's converted to some other format (binay for example)

[Vidar Berg]

The size of the .hex file doesn't correspond with the size of the actual image loaded to flash. See wiki here for more details. Easier way of determining the image size is to use the build output (.map) as explained here.

[RK]

The hex is just an ascii representation of a binary file which is about 2.5-3 times the length of the represented binary. It's the binary goes on the chip.