Disclaimers: The author is not responsible for any damage you incur by
running this program.  You run this at your own risk.

PATCHDOS is a simple program that implements Mike Brutman's DOS boot
sector patch, which allows a PCjr owner with more than 128K RAM the
ability to run almost any version of DOS they want.  The only
requirements are that there be an ASCII string in the boot sector 16 or
more bytes in length with which to store the patch.  For more details on
what the patch does and why, read HOWPATCH.TXT.

The program PATCHDOS is interactive; it prompts the user for which drive
to patch and asks for confirmation.  If a boot sector cannot hold the
patch, or any other error condition is encountered that would cause
problems, the program aborts with an explanation to the user.

This patch has been tested successfully on:

- MS-DOS 5.0 (requires STACKS=0,0 in CONFIG.SYS)
- MS-DOS 6.22 (requires STACKS=0,0 in CONFIG.SYS)
- IBM PC DOS 2000 (ie. PC-DOS 7.0, requires STACKS=0,0 in CONFIG.SYS)
- DR-DOS 6.0

This patch has been verified to NOT work on:

- FreeDOS (boot sector contains no strings to hold patch)

Use of a PCjr memory manager, such as JRCONFIG, is required to ensure
that programs load above the first 128K of RAM and aren't corrupted by
text or graphics updates.

--trixter@oldskool.org, 20130409

Trivia:

PC DOS 2000, to date, has the fastest "initial DIR" time of a 2 gig
partition of all DOSes tested.  The others took 53 seconds while PC DOS
2000 took 49 seconds.
