## Display Device Driver Reference for OS/2

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### SaveRestore VRAM

VIDEOPMI offers saving and restoring of the video buffer of SaveSize for each mode and is internally aware of the type of VRAM access it has to perform. The parameters taken into consideration when addressing the VRAM are BufferAddress, ApertureSize, and SaveSize. See [ModeInfo] section in PMI Sections.

If ApertureSize is equal to or greater than SaveSize, direct linear access to the BufferAddress is assumed. If this is not the case, the SetBank function is necessary in order to save and restore the entire on-screen VRAM. Granularity of a bank is assumed to be the ApertureSize. SaveSize should be set to reflect the logical line length programmed by the current mode, rather than just horizontal resolution.