SCRATCHSEG
assert ((SCRATCHSEG << 4) == SCRATCHADDR);
if (biosdisk (BIOSDISK_READ, current_drive, &geom, 0, 1, SCRATCHSEG))
if (biosdisk (BIOSDISK_READ, drive, &buf_geom, 0, 1, SCRATCHSEG))
sector, 1, SCRATCHSEG))