XnView Software

Hi, a few weeks ago I've bought my first DSLR (Canon SL1 / 100D). I photographed jpeg in the past with my old camera but now I want to switch to the RAW format (in case of my camera = CR2).
I made a few pictures and everything is fine with developing the CR2 files with the canon software DPP BUT..since the CR2 files are 20 something MB big I would like to crop some of the pics to get rid of the unwanted stufdf in pictures and hopefully make the CR2 smaller.
Now DPP isn't able to crop the CR2 file directly and save it as CR2 again. So I've searched the net for a tool that might can do this but I havn't found anything but some forums that talked about this topic but left me with not much more knowledge.
I know RAW is camera specific (although from what I've read most RAW formats seem to be based on the TIFF format) and its the dataoutput from the sensor/processor. But what I don't understand is how noone seem to be able to make a program that can crop a RAW file directly and save it as RAW again.
Can someone please give some insight into this topic. Is there really no way to get rid of some bytes of a RAW picture? Or is it just too much work to do.

Thanks

Yes, it is too much work to do and it doesn't worth it.

CR2 (like any other Raw) is a very odd format because in fact due of the nature of Bayer sensor in the file the R, G and B channels are stored separately and in a very different way than in a 'normal' file (TIFF or any other format) for example G (green) is "twice as much" than R and B and also there are 12 or 14 bit/per channel. Converting this to a normal image (a process called demosaicing) is quite complex and, in fact, it is hacked because the official specification of any raw file is proprietary and, of course, a trade secret of each company.

That's why only a part of the raw format is known to the 'outside world': the real image part which is got by reverse engineering. Hence modifying this and writing back the data in this very uncommon (and not totally known) format if a very hard task to do and the benefit is quite low. Remember that today the storage is (in general) very very cheap, especially when we think about photos.

Hence, IMHO the best path for you is to buy a newer (read: bigger and faster) HDD/SSD and/or CPU.