It was IBM's OEM version of MS-DOS, more or less. Random Google result: https://www.techrepublic.com/blog/classics-rock/my-dos-version-can-beat-up-your-dos-ver

It was IBM's OEM version of MS-DOS, more or less. Random Google result: https://www.techrepublic.com/blog/classics-rock/my-dos-version-can-beat-up-your-dos-version/ https://www.techrepublic.com/blog/classics-rock/my-dos-versi...