86-DOS 0.2

86-DOS 0.2, possibly also known as QDOS 0.2 while in development, was the third beta release of QDOS/86-DOS. It featured the line editor EDLIN.

This version had preliminary documentation created for it, but it was never released to the general public and only appeared as an exhibit in a 1986 lawsuit between Seattle Computer Products and Microsoft. Tim Paterson later scanned the documentation and uploaded it to his website.

New Features
Though not much different from QDOS 0.10, version 0.2 adds a line editor and has other minor changes to internals.

EDLIN
EDLIN is a line editor, created for 86-DOS. It was meant to last only 6 months, but ended up being the only text editor until MS-DOS 5.0 and is supported in all Windows NT versions up to Windows 10.

The creator, Tim Paterson, has called it the "quickest line editor I could imagine" and an "absurdity". Software critic Bill Machrone called a later version of 86-DOS' EDLIN "just as bad as any other line editor I have attempted to use".

History
EDLIN, being a line editor, was not a new concept. Its look, feel, and syntax have been compared to CP/M's ed, which itself is loosely similar to Unix's ed and its predecessor qed.

EDLIN was created out of need for a text editor - a key part of office work and assembly-language development. It was written in either one or two weeks.

Usage
EDLIN was a line editor, reading a text file line-by-line. Line numbers were printed along with each line.

To call EDLIN, use the command. If the file already exists, it will be opened - otherwise, it will be created and the message "New file" will be shown.

The editor contained commands for users to control the document. They are denoted by the asterisk symbol and appear after every line.

Though not described in detail, the preliminary manual states that global searching and text replacement are available.

Commands
The following list includes only newly confirmed commands, and not the ones already present in the list on the QDOS 0.10 page. They are all sourced from the preliminary manual.

Dumped Sections
The preliminary manual includes version 0.2's BOOT.ASM and DOSIO.ASM files.

Compared to the same files at the end of the version 0.3 manual, there some major differences. All differences are in the DOSIO.ASM file - the BOOT.ASM files are identical minus the system-dependent switches.

Though not described in detail, the preliminary manual states that global searching and text replacement are available.

Commands
The following list includes only newly confirmed commands, and not the ones already present in the list on the QDOS 0.10 page. They are all sourced from the preliminary manual.

Naming
This version's name is shrouded in mystery. It has never been mentioned in official 86-DOS documents, and only the existence of an operating system between QDOS 0.11 and 86-DOS 0.3 is known.

Version Number
The assumed version number - 0.2 - isn't certain. Though a version between 0.11 and 0.3 is probably 0.2, the addition of an extra "0" (0.20) is very possible. Also, as seen in later versions such as 0.42 and 0.56, the version number could be anything from 0.21 to 0.29.

86-DOS or QDOS
The more certain mystery is whether the OS was called 86-DOS or QDOS - an advertisement showcasing version 0.2 called it 86-DOS. The name "86-DOS" is supported by an article in Softalk for the IBM PC, where while discussing QDOS 0.11 mentions that the name "didn't stay QDOS very long".

However, version 0.2 may have been called QDOS in development and changed to 86-DOS for marketing purposes. At a talk during VCF West XIII, Tim Paterson explained that QDOS was an internal name, similar to how Windows 95 was codenamed Chicago during development. It is possible that before Paterson knew 0.2 was going to be advertised, he called it QDOS 0.2.