"If it's not broken, don't touch it"
For the longest time Zara used an MS-DOS based POS system, and hey, it worked.
For the longest time Zara used an MS-DOS based POS system, and hey, it worked.
But to your point you can basically go back to the archives of the 90s internet and go on a shopping spree of vulnerabilities for dos looking at Trojan/virus code.