scratch pad 
noun chiefly North American
1A notepad.He also keeps on that clipboard a scratch pad where he jots down ideas for a screenplay he's developing (he wouldn't share the details) and verses for his hobby as a spoken-word poet....
- Dom took another paper off the scratch pad from the bag of supplies that he still carried and began transferring the clue's symbols.
- Ash and Lari would exchange looks every few minutes while Dara scribbled numbers and letters down on a faded yellow scratch pad.
1.1 Computing A small, fast memory for the temporary storage of data.Rather than just being something of an open scratch pad, JotSpot lets people build their own software programs.