Very well, because OS/2 1.x introduced, for the first time in Microsoft's MS-DOS lineage, a fully-fledged VIO subsystem that abstracted TUI applications programming wholly away from touching the hardware. (GUI applications programming with VIO still required some low-level stuff. But TUI applications programming was entirely in terms of high-level console I/O with streams of characters and low-level console I/O with a 2-dimensional output buffer. There was no mixture of directly poking hardware and calling into the machine firmware.)

I regularly ran in 50-line VGA mode with zero problems. One could session-switch between full-screen OS/2 TUI programs (that were genuinely operating the hardware in VGA text mode, not simulating it with the hardware itself being used in graphics mode as became the norm with other operating systems much later and which OS/2 itself never got around to) and the Presentation Manager desktop.

I even had a handy LINES 50 command that wrapped the VIO mode change function, that I gave to the world as one of many utilities accompanying my 32-bit CMD, and which in 32-bit form was layered on top of a debugged clean room reimplementation of IBM's never-properly-shipped-outwith-the-Developers'-Toolkit 32-bit version of the VIO API.

You can still download it from Hobbes, today.

* https://hobbesarchive.com/?detail=/pub/os2/util/shell/32-bit...