Editing Apple DOS (section)

==Decline==
After 1980, Apple DOS entered into a state of stagnation as Apple concentrated its efforts on the ill-fated [[Apple III]] computer and its [[Apple SOS|SOS]] operating system. Two more versions of Apple DOS, both still called DOS 3.3 but with some bug fixes and better support for the new [[Apple IIe]] model, were released in early and mid-1983.

Without third-party [[patch (computing)|patches]], Apple DOS can only read floppy disks running in a 5.25-inch Disk II drive and cannot access any other media, such as hard disk drives, virtual [[Random-access memory|RAM]] drives, or [[Floppy_disk#3.5-inch_floppy_disk|3.5-inch floppy disk]] drives. The structure of Apple DOS disks (particularly the free sector map, which was restricted to part of a single sector) is such that it is not possible to have more than 400&nbsp;KB available at a time per drive without a major rewrite of almost all sections of the code; this is the main reason Apple abandoned this iteration of DOS in 1983, when Apple DOS was entirely replaced by [[Apple ProDOS|ProDOS]].

ProDOS retains the 16-sector low-level format of DOS 3.3 for 5.25&nbsp;inch disks, but introduces a new high-level format that is suitable for devices of up to 32&nbsp;[[Megabyte|MB]]; this makes it suitable for [[hard disk]]s from that era and [[Floppy_disk#3.5-inch_floppy_disk|3.5-inch floppies]]. All the Apple computers from the II Plus onward can run both DOS 3.3 and ProDOS, the Plus requiring a "Language Card" memory expansion to use ProDOS; the e and later models have built-in Language Card hardware, and so can run ProDOS straight. ProDOS includes software to copy files from Apple DOS disks. However, many people who had no need for the improvements of ProDOS (and who did not like its much higher [[memory footprint]]) continued using Apple DOS or one of its [[clone (computing)|clone]]s long after 1983. The Apple convention of storing a bootable OS on every single floppy disk means that commercial software can be used no matter what OS the user owns. A program called [[DOS.MASTER]] enables users to have multiple virtual DOS 3.3 [[disk partitioning|partitions]] on a larger ProDOS volume, which allows the use of many floppy-based DOS programs with a hard disk.

Shortly after ProDOS came out, Apple withdrew permission from third parties to redistribute DOS 3.3, but granted one company, Syndicomm, an exclusive license to resell DOS 3.3.<ref name="Exclusive License">{{cite web|url=http://apple2history.org/2010/11/18/even-apple-used-pirate-tools/|title=Even Apple Used Pirate Tools|author=Dean Esmay|date=18 November 2010 |access-date=2011-08-11| archive-url= https://web.archive.org/web/20110725012703/http://apple2history.org/2010/11/18/even-apple-used-pirate-tools/| archive-date= 25 July 2011 | url-status= live}}</ref>

Commercial games usually did not use Apple DOS, instead having their own custom disk routines for [[copy protection]] purposes as well as for performance.