Core OS

When initially previewing the Disk Operating System, it is suggested that in order to truly gain enlightenment as to the power available from DOS, you install:
1) FreeDOS or a later MS-DOS OS, 2) all required hardware drivers, 3) the Quarterdeck Expanded Memory Manager, 4) and the 4DOS command-line interpreter.


the Disk Operating System:
MS-DOS + a custom core set of Setup Utilities (ver 6.22) - Abandonware
~ MS-DOS (ver 3.30)

~ [MSDOS330 .zip]

a superior Memory Manager:
Quarterdeck Expanded Memory Manager (ver 9.0) - Abandonware

a superior Command Line Interpreter:
4DOS (ver 8.00) - Commercial made Abandoned Freeware

Background

One of the biggest misconceptions is that DOS is the entire suite of utilities that was originally bundled in a set of diskettes labeled "DOS". In truth, the MSDOS operating system consists of only two files, the Bootloader [named IO.SYS] which serves as an interface for a mainstream PC BIOS (antique PC clones that were not fully IBM PC compatible would replace this file with their own variant of the bootloader), and the Kernel [named MSDOS.SYS] which provides minimal core DOS OS services. By default, these files are located in the root directory of the bootable drive/partition, and have the Hidden, Read-only, and System file attributes set.

Additionally after the computer finishes booting, it will attempt to automatically load a Command Line Interpreter program. The CLI that shipped with MS-DOS is a lame interpreter named COMMAND.COM, which for numerous reasons should be replaced with a far more capable command line interpreter (such as the now free 4DOS CLI).

Most DOS documentation is actually focused on using specific utilities, rather than on the core OS itself or how DOS can interact with PC hardware. Keep in mind that to initially configure DOS you will also need to know about all of the pertinent hardware built into your specific computer, so that you can know which necessary hardware drivers to load. Offered here is an assortment of documents covering how to use DOS and write DOS utilities.

History of Modern Computing (*.pdf book) = The fascinating story of Computing
Microsofts Disk Operating System (*.pdf) = Historical overview of DOS
Using MS-DOS 6.22 (*.pdf book) = Operating System & Supplemental Utilities reference
Microsofts Undocumented Features (*.txt) = Undisclosed features of the Microsoft supplemental utilities
Advanced MS-DOS Batch File Programming (*.pdf book) = An excellent Batch File command reference
Threat Behind the Outlet (*.pdf) = Discussion of computer Power Protection
AMI BIOS Beep Codes (*.pdf) = BIOS fault beep code list
Port Addresses (*.jpg) = Port address list
Mythbusting (*.txt) = Tips for building a DOS PC
IBM PC Technical Reference (*.zip) = PC white papers from IBM
Magic Packet Technology (*.pdf) = Wake-On-Lan white paper
Ralf Browns Interrupt Lists (*.zip) = Lists of all known Interrupts
MSRef (*.zip) = Microsoft MS-DOS Programmers Reference
Source (*.zip) = Assembly Source Code for Microsoft DOS versions 1.1 and 2.0
Art of Assembly Language Programming (*.pdf book) + lessons = Assembly Language textbook

Preparation

Before installing DOS, it may be necessary to remove (Windows/Linux) files currently on the drive in question.

BIOS Cracker

CmosPwd (ver 5.0) - Freeware
= both DOS and Windows versions

Bootable Windows OS Extractor

XXClone (ver 0.58.0) - abandonware = (Last Win2k version)
= Windows only

Disk Data Extractor

TestDisk (ver 7.2) - Freeware
~ includes: PhotoRec (ver 7.2)
= both DOS and Windows versions

Disk Data Wiper

Wipe (ver 2.10) - Freeware
= both DOS and Windows versions

Occasionally you may have to copy files from an uncommon file system before reformatting. A hack for temporary drive access is to create and boot a "live" CD that starts (but does not install) an emergency reduced-capability operating system that understands the file system. Note that you may have to configure your computers BIOS so that it can boot from the CD.

Access the FAT12, and FAT16 file systems = MS-DOS
Access the VFAT, FAT32, and NTFS file systems = MS-Windows Preinstallation Environment
Access the HPFS file system = IBM eComStation
Access the BFS file system = Haiku
Access the FFS, UFS1, UFS2, EXT2, EXT3 file systems, and the Novell NWFS file system = FreeSBIE

NOTE: An outstanding alternative to MS-DOS is FreeDOS, not only because it incorporates many desirable architectural improvements, but because it moves 16-bit DOS out of corporate control and into the hands of the Public. People who desire to run legacy DOS software from the last millennia (sadly, mostly just retro-gamers these days) would be well served to use and support the FreeDOS project. Gamers having to use a recently manufactured computer to play their DOS games can still use DOS as their computers OS if they play their games under the DOS version of DOSBox-X.

CAUTION: It is strongly urged that you never use DISK Compression software, as it introduces instabilities (individual file compression software like *.ZIP is ok). Modern drives are now big enough to eliminate the need.
Also, avoid software Disk Caching (especially Microsoft SmartDrive), as DOS software caching is prone to loosing data. Adequate caching is now built into modern hardware, eliminating the need for software caching.