The following is a reposted explanation:
Recommended: a three-in-one general-purpose driver package
As computers now have more and more peripherals, the drivers for those peripherals that are not supported at the core level have one after another become memory-resident. Together with all sorts of other TSR programs, this has kept the use of memory below 1 MB in the DOS environment extremely tight. For this reason, quite a few programs have been designed to ease this problem. Most of them are of the “open source” kind, such as QEMM and so on.
The Multimedia Cloaking utilities recommended here (hereafter abbreviated as MMCLK) are a sort of three-in-one driver package. It can separately replace the drivers for the mouse, CD-ROM, and disk cache. The more drivers you originally used, the more memory this software can save for you, and it also reduces the possibility of system crashes.
I. Main contents of MMCLK:
The core program of the MMCLK package is CLOAKING.EXE. After MMCLK is installed, it stays resident in memory. Its function is to provide an API interface for the following three drivers. As long as you use MMCLK's drivers, this core program must be loaded into memory first.
1. Disk cache driver (CACHECLK.EXE)
It can ensure compatibility with SMARTDRV.EXE that comes with DOS. Its features are not only low resource usage, but also faster speed than SMARTDRV.EXE. The exact amount of memory it uses depends on your settings. It has two loading methods:
(1) Load it in CONFIG.SYS:
INSTALL=C:\MMCLK\CACHECLK.EXE K=2048 WK=2048 WB=16 WRITECACHE WD=54
(2) Load it in AUTOEXEC.BAT:
C:\MMCLK\CACHECLK.EXE K=1856 WK=1856 WB=4 WRITECACHE WD=54
2. CD-ROM driver (CDEXCLK.EXE)
It uses only 2K of memory to replace MSCDEX.EXE, and is fully compatible with Microsoft's MSCDEX. It needs to be loaded in CONFIG.SYS:
DEVICE=C:\MMCLK\CDEXCLK.EXE /D:MSCD001 /L:D
At the same time, the package also includes an MSCDEX.EXE for friends who do not use CDEXCLK.EXE:
C:\MMCLK\MSCDEX.EXE /D:MSCD001 /L:D
It uses only 3K of your memory!
3. Mouse driver (MOUSECLK.EXE)
It needs even less memory (under 1K) to replace a mouse driver of more than ten K, thus greatly saving memory. It is also loaded in CONFIG.SYS:
DEVICE=C:\MMCLK\MOUSECLK.EXE
According to the author's tests, all of the above programs can be loaded into upper memory.
II. Installation of the MMCLK package:
After extracting the archive, just run SETUP.EXE and it will automatically modify your settings and correctly install these drivers for you.
The installer first looks for CONFIG.SYS (the system configuration file) in the root directory, determines whether it uses multiple configurations, and if so, lists the various configurations so you can choose which configuration item to install. After making your choice, it enters the main configuration menu. The settings for each installation option are explained below:
1. Disk cache installation options:
(1) Disk Cache Size Determines the size of the disk cache.
(2) Cache Size under Windows Determines the size of the disk cache under Windows.
(3) Delay Delay for background write operations (unit: seconds).
(4) Buffer Size Determines the size of the write buffer.
(5) Other Media Determines whether to cache floppy drives and CD-ROM drives.
2. CD-ROM installation options:
(1) CD-ROM Device Names Enter the device name of your CD-ROM drive; up to 4 CD-ROM drives can be installed.
(2) First drive letter The drive letter of the first CD-ROM logical drive.
3. Mouse installation options:
(1) Left/Right Button Swap Swap the left and right mouse buttons.
(2) Middle/Right Button Swap Swap the middle and right buttons (for three-button mice only).
(3) Acceleration Mouse acceleration.
(4) Orientation Correct the mouse direction, allowing any of the four directions—up, down, left, or right—to be specified as the mouse's forward direction.
(5) Blink Rate Adjust the blink rate of the mouse in text mode.