Before the advent of automation, librarians assigning call
numbers in this way would have notebooks prepared in advance
which would help them check sequences but also note numbers that
were occupied. They could also use a card shelflist (also known as
topographic) catalogue for the same purpose.
One of the main inconveniences with the arrangement of
books with accession numbers is in the fact that the same work
would be scattered on the shelf depending on the time of their
acquisition. This was especially inconvenient before library
automation when users ordering books from the catalogue would
have to make a note of the accession number of each copy of a title
and the library staff would have to check different places on library
shelves to see whether there is any copy of the work available.