The Tungsten PDA

As this analysis will be profound, advances that are going to treat it reboots randomly experienced by users of Palms with the new NVFS memory system (especially the first two teams who implemented: the Tungsten T5 and Treo 650), the Because of them, and how it can be solved.

Since the launch of the Tungsten T5, back in 2004, Palm has implemented the new devices in its memory system called NVFS, which is an acronym for Non-Volatile File System. Is the use of flash memory (the same type of SD memory cards) as the main memory of the PDA. The flash memory does not need continuous power to preserve the information, which it needed the previous used memory, type of RAM, similar to that of computers.

This has two advantages: lower energy consumption (which greatly improves the autonomy) and that the memory is not lost when the battery runs down completely. But the NVFS also brought drawbacks. More precisely, the implementation of it. And to understand the problem, we must first know exactly how the new system memory.

In PDAExpertos is very well explained. I will summarize it to the minimum necessary to understand the rest of the analysis. For a more in-depth reading, I recommend his article.

The Palm Tungsten T5 prior to the scheme had the following report:

• On the one hand a memory chip ROM with the operating system, programs and libraries that came from the factory. ROM memory, as its name suggests, is read-only, we can not modify.
• And a RAM chip in turn with two parts: the fact that we agree, where they are installed programs, documents are saved, etc., and a small party to which we can not access, called Dynamic Heap, who is the used by programs when they are executed. Both sides could identify with the hard disk and main memory of a computer, respectively.

The Palm NVFS with a different structure:

• A flash memory chip, which is in an area, the operating system, libraries and programs that come from the factory (next to the ROM of the previous models), and in another part of it, the memory for our use, where to store the programs that we installed, documents and so on. Let's say it's like a computer hard drive, in which the operating system is in a directory, and other programs and data.
• But there is still a memory chip RAM. And you may ask why? The reason is that a program can not run directly into the flash memory, it must do so in RAM. Therefore, each time you run an application, it must first be copied to RAM. This makes our Palm in a transparent, and the delay that occurs is imperceptible.
  This RAM memory that contains the Dynamic Heap said before, and also an area called DbCache where are copied, as we say, the programs to run. Once you close a program, DbCache is cleared from the site to make it to the next program that runs (and should be at least ...). And this cache is precisely the cause of all problems.

In short, the famous DbCache, about 10Mb, to which we can not access directly, as we have seen, for internal use of the operating system. And the problems of "Not enought memory ..." that gives the Blazer, or restarts because of errors "Fatal Exception" or "Memory full" which occur when opening a program that consumes lots of memory, or without apparent cause in some cases , Are due to its peculiar way of functioning. But that's what we'll see in the next post, because it is already quite dense.

Posts in this series:

• Avoid crashing into the new Palm with NVFS (I)
• Avoid crashing into the new Palm with NVFS (II)
• Avoid crashing into the new Palm with NVFS (and III)

By: Mark Gonzalez Troyes in Palm Tricks
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• How to automate 'soft resets' to recover memory and avoid crashing
• Avoid crashing into the new Palm with NVFS (and III)
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Labeling: memory, nvfs, Palm, Palm, PDA, a problem

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