Theodore Y. Ts'o is a software developer known for for his contributions to the Linux kernel particularly with the file systems. He is the primary developer and maintainer of e2fsprogs, the userspace utilities for the ext2 and ext3 filesystems, and is a maintainer for the ext4 file system.
In 1994, he created /dev/random and the corresponding kernel driver, which was Linux's (and Unix's) first kernel interface that provided high quality cryptographic random numbers to user programs.