What would happen if we needed to upgrade to a new disk drive—one with more heads, or one with more cylinders, or one with more sectors per cylinder? We had to write a special program to read in the old data from the old disk, and then write it out to the new disk, translating all of the cylinder/head/sector numbers. We also had to change all the hard-wiring in our code—and that hard-wiring was everywhere! All the business rules knew the cylinder/head/sector scheme in detail.
