diff --git a/src/minivhd_io.c b/src/minivhd_io.c
index 520a5f2..cc6f482 100644
--- a/src/minivhd_io.c
+++ b/src/minivhd_io.c
@@ -98,4 +98,15 @@ int mvhd_diff_read(MVHDMeta* vhdm, int offset, int num_sectors, void* out_buff)
         buff += MVHD_SECTOR_SIZE;
     }
     return truncated_sectors;
+}
+
+int mvhd_fixed_write(MVHDMeta* vhdm, int offset, int num_sectors, void* in_buff) {
+    int64_t addr;
+    int transfer_sectors, truncated_sectors;
+    int total_sectors = vhdm->footer.geom.cyl * vhdm->footer.geom.heads * vhdm->footer.geom.spt;
+    mvhd_check_sectors(offset, num_sectors, total_sectors, &transfer_sectors, &truncated_sectors);
+    addr = (int64_t)offset * MVHD_SECTOR_SIZE;
+    fseeko64(vhdm->f, addr, SEEK_SET);
+    fwrite(in_buff, transfer_sectors*MVHD_SECTOR_SIZE, 1, vhdm->f);
+    return truncated_sectors;
 }
\ No newline at end of file
diff --git a/src/minivhd_io.h b/src/minivhd_io.h
index 30c4d5b..2680b35 100644
--- a/src/minivhd_io.h
+++ b/src/minivhd_io.h
@@ -6,4 +6,7 @@ int mvhd_fixed_read(MVHDMeta* vhdm, int offset, int num_sectors, void* out_buff)
 int mvhd_sparse_read(MVHDMeta* vhdm, int offset, int num_sectors, void* out_buff);
 int mvhd_diff_read(MVHDMeta* vhdm, int offset, int num_sectors, void* out_buff);
 
+int mvhd_fixed_write(MVHDMeta* vhdm, int offset, int num_sectors, void* in_buff);
+int mvhd_sparse_diff_write(MVHDMeta* vhdm, int offset, int num_sectors, void* in_buff);
+
 #endif
\ No newline at end of file