SMVDD.SYS
This driver provides DOS and WIN-OS/2 digital video support. If you do not use DOS or WIN-OS/2 that require digital video support you can remove this driver from CONFIG.SYS.
One of the features of SMVDD.SYS is (or rather: was) to provide a function to map a physical address (in this case: the screen aperture) to a linear address valid in the caller's address space so that you can access the screen and write to it like you would write to memory. This functionality is provided by SCREEN01.SYS in any OS/2 system up to present day.