Doublespace  Drivespace - Stacker - Double Disk

These utilities are meant to double hard drive space by compressing programs 
and files. They all work to some extent but you should be aware of what can 
happen.

These utilities build a compressed container file that acts like another disk 
drive and a drive letter is assigned to it. It can be swapped back to Drive 
letter C so that it becomes somewhat transparant to software.

The original or real drive C is reassigned another drive letter, like H for 
host. That contains the operating system and a container file. There are some 
programs that simply will not work on a compressed drive such as QEMM memory 
manager. Windows swap file also will not work on the compressed drive and must 
be allocated to the host drive.

One of the biggest problems is the drivers required to make it work take up so 
much memory that you can actually run out of the critical DOS 640 K memory 
area where your programs must first be loaded. This happens when you run a 
compression utility plus other drivers for CD ROM, Sound Card, Label Printer, 
and others. The memmaker program just will not allow you to load enough of 
these drivers high. There are some programs that just will not work with them. 

Another major disadvantage is that this compression slows down your system 
considerably. It's like running in slow motion. The reason is logical. All your 
data and programs are stored in compressed format and to run them, the computer
must decompress them and then load it into memory each time they are accessed.
It's an extra operation for the computer. Compression actually slows your 
system down by almost 50 percent.

At some point in time, these compression programs just seem to start going
crazy for no reason and suddenly you find a few errors. That's the start of 
trouble and it just keeps getting worse from there. Hard drives are intricate 
enough without compression. It's one more thing to go wrong. If your want to 
be productive, buy a bigger hard drive.