saving designs in virtual memory to disk

hi,

I am opening a cell view with dbOpenCellViewByType() command in read mode, and copying this view to some other view with the dbCopyCellView(...x...) command. 

 Now I am opening the copied view in append mode and making some edits on this layout view, and saving the same with dbSave(), and closing the view with dbClose() command. and also closing the view that is opened in read mode.

Now I am facing two problems,

The opened views are still existing in the virtual memory, they are not saving into the disk. how to write it into disk, and free virtual memory.

And I am getting a warning *Attempt to save read only design*...  (why this warning, i am not saving the read mode opened design.)

Is There  any commands to save the design in virtual memory to disk...Please help me

Thanks

Harish