Will, You're right, Windows DOES NOT handle the serial port timing correctly. That is why rebooting from the shut down menu (you are actually using the "dosstart.bat" when you do this) is no good. See this link for more info:
http://www.pcforrest.freeserve.co.uk/dosstart_bat.htm
Here's a quick quote from the article:
"By default, the machine will not reboot. Windows is merely unloaded, although certain aspects of the Windows shell remain in force, such as long filename support." - essentially, some aspects of Windows remain, including TSR (Terminate/Stay Resident) programs.
Using the shortcut I mention does not go this route, it actually reboots the machine into DOS using a different procedure the same as a boot disk. There is no part of Windows loaded to cause timing issues.
I never claimed the boot disk wasn't valid, it is! I just stated I've seen my way work when a boot disk didn't, especially with larger RSS which requires 4MB of extended memory to run (MTSX, MCS). Yes, you can modify your Autoexec & config files to do the same, but most people prefer to click something these days.
As far as taking chances, I still promise to send Monty my first corrupted codeplug. I'm somewhere in the area of 7000 radios programmed, on 7 or 8 different computers, with no corruptions yet.
You can quibble over the order, but here's how I see it (processor speed issues aside):
1st: DOS only computer - never a doubt
2nd: DOS only partition - have someone else do it for you if you can't.
3rd: MS-DOS mode for games with EMS & XMS Support.
4th: DOS boot disk (tied for third if you can edit the autoexec & config yourself).
5th: (bad) rebooting from shut down menu or choosing "command prompt only" when booting. - Both essentially Windows without the GUI.
Last: DOS window - This one will turn the radio into a brick, I hope everyone has enough sense not to do it.
My 2 Canadian cents, about .0002 cents American.
Todd