Jump Development Banner

RC Icon

RAM Charger 8 For Macintosh
Home | Search | Support | Contact | Download | Order


What is Memory? And RAM? And Disk space?


(Tech0021A -- 04/19/98)


Great confusion exists from the popular casual use of the term "memory". Many people think the term "memory" is a synonym for RAM, or for Disk space. Actually, the term "memory" is a broad term which is neither a synonym for RAM nor Disk space, though both may be used to provide "memory".

Apple defined Mac memory as a general term for the logical working space where software operates; this definition is illustrated by its use in the "About This Mac" window of the first Mac. The "Total memory" space is ususally provided by RAM (which is relatively fast), but may also be provided by other hardware resources - like disk space - using virtual memory techniques.

On computers where virtual memory is disabled , your "memory" is the same as your RAM; however, when virtual memory is enabled your "memory" may exceed your RAM (using other hardware resources - perhaps your disk space, which is slower than RAM).

So "memory" is a broad term describing the space available to software, meant to cover a wide variety of configurations.

This is all so subtle...Why do we care?

The popular misconception that "memory" and RAM are the same has been exploited by RAM Doubler literature to imply that RAM Doubler (and thus virtual memory) does the same thing as RAM Charger, and that RAM Doubler is functionally different than Apple Virtual Memory. Because Connectix substitutes the word "memory" in its literature where the term RAM is appropriate, there is confusion in the market about what RAM Doubler is, and why RAM Charger is fundamentally different. In truth, since the issue appears subtle, there might be confusion even if the proper words were used; however Connectix appears to have gone out of their way to add confusion rather than remove it.

RAM Doubler's virtual memory use of RAM in a dynamic way is not the same as using memory in a dynamic way. The issue is important because RAM Charger solves problems by using memory in a dynamic was, that are not solved by just having more traditional memory as provided by RAM Doubler. By stating that they use memory in a dynamic way, when in fact they mean RAM in a dynamic way, they mislead users into thinking that RAM Doubler accomplishes things that it does not

In fact, RAM Doubler propaganda is so convincing that they have even fooled themselves into making false claims.

The FALSE RAM Doubler (virtual memory) "Reclaim" Myth

RAM Doubler is documented to reclaim "memory" not in use by an application (p11 of the RAM Doubler Manual: RAM Doubler 2 dynamically reclaims any unused memory and makes it available to run additional applications). Since this is what RAM Charger does, by allowing applications to start using less memory, many people think the same thing is going on. Since this issue is at the very core of RAM Charger's purpose, it is understandably an important issue.

In fact RAM Doubler does not reclaim "memory". This is apparent if you start two applications each having a preferred size of half of your memory. In such case, you will see that RAM Doubler documents the unused memory as being reclaimed, yet none is available to start other applications. For example, make two copies of the application "SimpleText". Next, set the preferred size for these applications to half the size of your Total Memory. Now open both applications and examine About This Mac.

Here are screen shots of this example with RAM Doubler. Note that RAM Doubler says 31 megs are reclaimed to start applications; however there is actually almost no memory to start applications. This example may seem contrived, but it is not. This example accurately represents the common real world situations that RAM Charger was created to solve.

Of course, you must do this test with RAM Charger disabled for these applications, since RAM Charger does reclaim "memory". If RAM Charger is enabled for SimpleText under the same configuration, each SimpleText application will start small, yet each will have access to the unused "reclaimed" memory. Here are screen shots of the same sitatution with RAM Charger. Note, in this case there really is 31 megs available.

RAM Doubler does reclaim RAM in exactly the same way Apple Vitual Memory does; however this does not help you in the way they claim. It reclaims RAM this by taking the "unused" memory and moving it to "backing storage", making "faster" RAM available for memory that is in use. This is also what all virtual memory systems do, including Apple virtual memory. What is important is that reclaiming RAM does not allow application's to grow and shrink dynamically, and thus they can still run out of memory prematurely. In fact, even RAM Doubler's own liturature suggests that you start applications in the same fixed "preferred" sizes you used before RAM Doubler.

All of this is not to imply that virtual memory is not valuable, only that it does not do what RAM Charger does. Each technique has its own value.

More details about RAM

Memory is not a synonym for "RAM", which is a very specific term which refers the physical hardware. RAM refers the volitile physical hardware which is able to store and retrieve information relatively quickly. RAM stands for Random Acess Memory, meaning that computers can store and retrieve information at any random location. The memory is volitile, since the information stored is lost if power is turned off.

Applications can only operate from within real RAM, since the CPU can only obtain instructions from RAM. When virtual memory is disabled, all "memory" is in real RAM. However, when virtual memory is enabled, some "memory" is in real RAM and other memory is in "backing storage" since there is insufficient RAM. As a result, to perform operations in backing storage all processing must halt while the operations are moved from backing storage (relatively slowly) into real RAM. This is why virtual memory can cause slowdowns, or jerky operation.

More details about Disk space

Memory is not a synonym for "Disk space", which is a very specific term which refers the physical hardware. Though it is technically correct to call disk space "permanent memory", or "disk memory", or some other "qualified" kind of "memory", "memory" by iteslf refers to the working space for applications as shown in the Finder's "About This Mac" window and not your general hard disk storage space. Unfortunately, this leads to confusion, allowing users to think "memory" may refer to their disk storage space.

Disk storage space is where applications and information are permanently stored. Also, disk space is often used as "backing storage" when virtual memory is enabled. Disk memory retains the information even when no power is applied to the disk, and disk space is cheaper than RAM. However, accessing information stored on a disk is magnitudes slower than accessing information in RAM.


See Also

Home | Search | Support | Contact | Download | Order
Translate to: Français | Deutsch | Italiano | Português | Español

Please direct corrections and comment to RAMCharger (at) RAMCharger.com

Copyright © 1995-98 Jump Development Group, Inc. All rights reserved. Jump, OptiMem, RAM Charger, and More About This Mac are trademarks of Jump Development Group, Inc. Apple and Macintosh are registered trademarks of Apple Computer, Inc. All other trademarks are the property of their respective holders.