https://en.wikipedia.org/wiki/IBM_Personal_Computer_XT
IBM made several submodels of the XT. The 3270 PC, a variant of the XT featuring 3270 terminal emulation, was released in October 1983.. Submodel 068 and 078, released in 1985, offered dual-floppy configurations without a hard drive as well, and the new Enhanced Graphics Adapter and Professional Graphics Adapter became available as video card options.. In 1986, the 256–640 …