Antiques code show Microsoft has released the source for another of its relics. This time, it's 86-DOS 1.00 getting the open source treatment, and a whole lot more for retro enthusiasts. The release comes a year after Microsoft set the source for MS-DOS 4.0 free, but it includes a lot more than just the bones of an old operating system. According to a post by Microsoft's Stacey Haffner and Scott Hanselman, "The listings include sources to the 86-DOS 1.00 kernel, several development snapshots of the PC-DOS 1.00 kernel, and some well-known utilities such as CHKDSK." "Not only were these assembler listings, but there were also listings of the assembler itself!" It is quite the treasure trove of information, and a throwback to an era when printouts were your friend for storing source code.…