Implementing a spellchecker with limited memory in the 1970s led to a lossless compression algorithm still in use today.In 1975, AT&T programmers used Unix as a text processor and needed a functional spell-checking system.The challenge was fitting a 250 kb file into just 64 kB of RAM.Douglas McIlroy developed an algorithm that used 14 bits of memory per word, achieving impressive compression for the time.