MS-DOS Memmaker versus Helix Netroom 3.0. DOS Memory Management: How much 640K RAM can we recover?

MS-DOS memory management was an important thing back in the early 1990s until the advent (generally) of Windows 95 and NT.
In those days, DOS programs often required a certain amount of the 640K RAM free for their use, and that was also shared with the TSRs.
What is a TSR?
A terminate-and-stay-resident program (commonly TSR) is a computer program running under DOS that uses a system call to return control to DOS as though it has finished but remains in computer memory so it can be reactivated later. This technique partially overcame DOS's limitation of executing only one program, or task, at a time. TSRs are used only in DOS, not in Windows.
Some TSRs are utility software that a computer user might call up several times a day, while working in another program, using a hotkey. Others serve as device drivers for hardware that the operating system does not directly support.

In our circumstance, we have several TSRs which are device drivers for items that MS-DOS cannot directly control:
Mouse
CDROM
Expanded Memory

Index:
0:00 Introduction and the hardware
3:40 MS-DOS 6.22 and Helix Netroom 3.0
4:28 FDisk and Format C: and fresh MS-DOS 6.22 installation
5:43 Fresh DOS and installing the mouse, CDROM, and EMM386 TSRs
7:26 Running MEMMAKER
9:29 Installing and exploring Helix Netroom 3.0
12:57 Running Helix Netroom 3.0
15:28 Comparing the memory results and final thoughts