Review and Testing of Connectix RAMDoubler Software

Mr. Fahrenheit

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Sep 2, 2021
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A little while ago, I made a comment on a YouTube video about RAMDoubler. Another member of that community and I started talking back and forth because they maintained the position that RAMDoubler was a complete hoax and a scam. They held the position that RAMDoubler was simply enabling virtual memory and nothing more.

I knew that RAMDoubler wasn’t a hoax and also wasn’t just virtual memory, so I decided to scientifically prove it.

Here is the resulting video which proves RAMDoubler actually did what it was advertised to do:


Information I’ve gathered from the internet is that RAMDoubler had important parts.

1. It divided your RAM into 2 partitions. The first area it did not touch. I’m unsure if this was 1/4 of real RAM, 1/3 or even 1/2, but the numbers thrown around are 1/3.

2. It converted the second partition of RAM into a RAM disk, that was not mounted to the file system.

3. It used a driver level compression algorithm on the RAM disk to compress it on-the-fly.

4. It enabled its own virtual memory system to use the invisible RAM disk as a virtual memory scratch.

What this means is code loaded into background memory gets paged out to the VM on the RAM disk, and compressed using the drive level compression. Because this is happening on fast RAM instead of a hard disk, it is much much faster than traditional virtual memory.

While it didn’t allow you to run an app requiring 8MB free ram on a machine like the IIsi with 5MB doubled to 10MB, for example, it did allow you to run multiple apps where the amount of needed memory combined adds up to double the system memory.

On a Mac with 4MB of system RAM, it gives about 5MB free for programs, but you’re still constrained working that 5MB to not exceed a few MB per running program.

If you have watched the video up to reading this point you can see how this works. If you haven’t yet watched the video, do it now! It shows exactly how it works.

The ideal use case for RAMDoubler was a Mac with about 8-12MB of physical RAM with the user wanting to multitask between paint, spreadsheet, word processing, etc. allowing all to be simultaneously run. Without more RAM or RAM Doubler the alternatives were either not running what you want all at once, or resorting to the painfully slow virtual memory under System 7.

The PowerPC Macs ushered in a faster virtual memory with its faster disk IO but there were still lots of gains using RAM Doubler on a PPC Mac as well.

Connectix later went on to create other “doublets” including Speed Doubler, which had a better 68k emulation than Apple’s and also possibly prioritized threads better (I’ve not done any research into SpeedDoubler, however).

What are your memories of this great utility?
 
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