Editing Apple DOS (section)

==Version history==
When [[Apple Inc.|Apple Computer]] introduced the [[Apple II (original)|Apple II]] in April 1977, the new computer had no disk drive or [[disk operating system]] (DOS). Although Apple co-founder [[Steve Wozniak]] designed the [[Disk II]] controller late that year, and believed that he could have written a DOS, his co-founder [[Steve Jobs]] decided to outsource the task. The company considered using [[Digital Research]]'s [[CP/M]], but Wozniak sought an operating system that was easier to use. On 10 April 1978 Apple signed a $13,000 contract with [[Shepardson Microsystems]] to write a DOS and deliver it within 35 days. Apple provided detailed specifications, and early Apple employee [[Randy Wigginton]] worked closely with Shepardson's Paul Laughton as the latter wrote the operating system with [[punched card]]s and a [[minicomputer]].<ref name="terdiman20130403">{{cite web | url=http://news.cnet.com/8301-13579_3-57577597-37/the-untold-story-behind-apples-$13000-operating-system/ | title=The untold story behind Apple's $13,000 operating system | work=CNET | date=2013-04-03 | access-date=April 4, 2013 | last=Terdiman | first=Daniel}}</ref>

There was no Apple DOS 1 or 2.  Versions 0.1 through 2.8 were serially enumerated revisions during development, which might as well have been called [[software build|builds]] 1 through 28. Apple DOS 3.0, a renamed issue of version 2.8, was never publicly released due to bugs. Apple published no official documentation until release 3.2.<ref>{{cite web|url=http://www.laughton.com/Apple/Apple.html |title=Apple Computer |website=Laughton.com |access-date=2013-06-14}}</ref><ref name="Apple2_history">{{cite web |url=http://apple2history.org/history/ah14.html#03 |title=Apple II History » 14-DOS |website=Apple2History.org |access-date=2013-06-14 |archive-url=https://web.archive.org/web/20100710012134/http://apple2history.org/history/ah14.html#03 |archive-date=2010-07-10 |url-status=dead }}</ref>{{sfnb|Worth|Lechner|1981|pages=2-1,2-2,2-3}}

'''Apple DOS 3.1''' was publicly released in June 1978, slightly more than one year after the Apple II was introduced, becoming the first disk-based [[operating system]] for any Apple computer. A bug-fix release came later, addressing a problem by means of its {{code|MASTER CREATE}} utility, which was used to create Apple DOS master (bootable) disks: The built-in {{code|INIT}} command created disks that could be booted only on machines with at least the same amount of memory as the one that had created them. {{code|MASTER CREATE}} includes a self-relocating version of DOS that boots on Apples with any memory configuration.

'''Apple DOS 3.2''' was released in 1979{{sfnb|Worth|Lechner|1981|page=2-2}} to reflect changes in computer booting methods that were built into the successor of the Apple II, the Apple II Plus. New [[firmware]] included an auto-start feature which automatically found a [[disk controller]] and booted from it when the system was powered up&mdash;earning it the name "Autostart [[Read-only memory|ROM]]".{{Citation needed|date=February 2019}} DOS 3.2.1 was then released in July 1979 with some minor bug fixes.<ref  name="Apple2_history" />{{sfnb|Worth|Lechner|1981|page=2-2}}

'''Apple DOS 3.3''' was released in 1980. It improves various functions of release 3.2 including a rewrite of the RWTS to make it faster,{{sfnb|Worth|Lechner|1981|page=2-2}} while allowing for large gains in available [[floppy disk]] storage. The newer P5A/P6A [[Programmable ROM|PROMs]] in the disk controller enable the reading and writing of data at a higher density, so 16 [[disk sector|sectors]] (4&nbsp;KiB) can be stored per [[track (disk drive)|track]] instead of 13 sectors (3.25&nbsp;[[Kibibyte|KiB]]), increasing capacity from 113.75&nbsp;KB to 140&nbsp;KB per side{{snd}} 16&nbsp;KB of which is used by [[filesystem]] overhead and a copy of DOS, leaving 124&nbsp;KB for user programs and data. DOS 3.3 is, however, not [[backward compatible]]; it cannot read or write DOS 3.2 disks. To address this problem, Apple Computer released "MUFFIN", a utility to migrate Apple DOS 3.2 files and programs to version 3.3 disks. Apple never offered a utility to copy in the other direction. To migrate Apple DOS 3.3 files back to version 3.2 disks, someone wrote a "NIFFUM" utility. There are also commercial utilities (such as ''[[Central Point Software|Copy II Plus]]'') that can copy files between either format (and eventually [[Apple ProDOS|ProDOS]] as well). Release 3.3 also improves the ability to switch between Integer BASIC and Applesoft BASIC, if the computer has a language card ([[Random-access memory|RAM]] expansion) or firmware card.