RAM Charger 8
December 8, 1997
RAM Charger is a sophisticated memory manager for the Macintosh. I works on any Mac (compare this with RAM Doubler which requires a 68030 or better and at least 8 MB RAM). The current version works transparently, allowing you to simply install it and forget it.
I first used Jump Development's OptiMem RAM Charger memory management software with version 1.5.x in late 1993. At the time, only power users had 8 MB RAM - other users might have a 4 MB LC, 5 MB IIsi, or 4-6 MB PowerBook 170. With System 7 weighing in at over 2 MB plus all the important additions (Suitcase, Retrospect Remote, ATM, PopChar, MenuChoice, Pyro, etc.), OptiMem gave these users room to run Microsoft Word and FileMaker at the same time.
Over the years, we upgraded almost every Mac to 8 MB or more and discovered RAM Doubler. It was an easier solution than OptiMem since you didn't have to configure it for specific applications.
But RAM Doubler and RAM Charger are really very different programs. Both allow you to run more programs with a limited amount of physical memory. RAM Doubler does it by emulating virtual memory, using RAM instead of the hard drive when possible. It does nothing to change the way Mac software uses memory.
That's the big difference between RAM Doubler and RAM Charger. Your Mac normally allocates a fixed amount of memory to each application, most of which remains unused. If you don't need all the memory, it is not available to other applications. But if you need more, you need to manually resize the program, which only causes it to reserve still more unused memory most of the time.
For instance, I manage several email lists using Macjordomo. To allow the large attachments that some users send (despite repeated requests not to), I've given the program 2,000K. RAM Charger drops that to 1,500K. Similarly, MacHTTP had 1,500K allocated, but RAM Charger reduced that to 450K.
If I had manually reduced the memory footprint of these programs, they would work most of the time, but eventually choke when they needed more memory. Then I'd have to quit the application, increase application size, and relaunch it. If that didn't provide enough RAM, I would have to repeat the process. This is true whether I am using conventional memory, virtual memory, or RAM Doubler.
But RAM Charger provides the needed memory on the fly. It allocates just enough memory when it is needed, then frees it for future use. This is called dynamic memory allocation and is a far more sophisticated form of memory management than virtual memory. Best of all, RAM Charger is fully compatible with virtual memory and RAM Doubler, offering the best of both worlds when you don't have enough physical RAM.
Jump Development was kind enough to provide several copies of RAM Charger for review and evaluation. I have been using it on my Mac II and 7600 for some time and find it remarkably stable. It's also nice to see that my 7600 hardly ever has to use virtual memory any longer.
I've been moving RAM Charger around and gathering feedback.
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