While trying to optimize the elementary OS performance, Sergey Davidoff stumbled upon a project called compcache that creates a RAM based block device which acts as a swap disk, but is compressed and stored in memory instead of swap disk (which is slow), allowing very fast I/O and increasing the amount of memory available before the system starts swapping to disk. compcache was later re-written under the name zRam and is now integrated into the Linux kernel.