True non-volatile ram - Yes or No?

I have never been much of an Apple person so I am both amused and annoyed by the lack of information which ships with the Touch. The "available online" Features Guide is helpful but even it is lacking in many ways.
Question: Does the Touch have true non-volatile ram? That is, if the device's battery becomes totally, completely, drained, will everything (music, photos, mail, contacts, etc) still exist in memory once it has been recharged? Or will the device need to be "restored" from the host PC?

Hi iTouchMe,
I do think so (however, I'm not 100% sure). Actually my battery drained completely once and I didn't lose any content.
Hope this helps!
!http://signatures.mylivesignature.com/54486/122/A57996D55BE7ABB4A67DE686D381A27 4.png!

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JMM: legal to optimize non-volatile flag out of particular loop condition?

Does Java Memory Model allow JIT compiler to optimize non-volatile flag out of loop conditions in code like as follows...
class NonVolatileConditionInLoop {
private int number;
private boolean writingReady = true; // non-volatile, always handled inside synchronized block
public synchronized void setNumber(int n) {
    while (!writingReady) { // non-volatile flag in loop condition
      try { wait(); }
      catch (InterruptedException e) { e.printStackTrace(); }
    this.number = n;
    this.writingReady = false;
    notifyAll();
public synchronized int getNumber() {
    while (writingReady) { // non-volatile flag in loop condition
      try { wait(); }
      catch (InterruptedException e) { e.printStackTrace(); }
    this.writingReady = true;
    notifyAll();
    return number;
}...so that it will execute like this:
class NonVolatileConditionInLoopHacked {
private int number;
private boolean writingReady = true; // non-volatile, always handled inside synchronized block
public synchronized void setNumber(int n) {
    if (!writingReady) { // moved out of loop condition
      while (true) {
        try { wait(); }
        catch (InterruptedException e) { e.printStackTrace(); }
    this.number = n;
    this.writingReady = false;
    notifyAll();
public synchronized int getNumber() {
    if (writingReady) { // moved out of loop condition
      while (true) {
        try { wait(); }
        catch (InterruptedException e) { e.printStackTrace(); }
    this.writingReady = true;
    notifyAll();
    return number;
This question was recently discussed in [one of threads|http://forums.sun.com/thread.jspa?messageID=11001801#11001801|thread] at New To Java forum.
My take on it is that optimization like above is legal. From the perspective of single-threaded program, repeated checks for writingReady are redundant because it is not modified within the loop. As far as I understand, unless explicitly forced by volatile modifier (and in our case it is not), optimizing compiler "has a right" to optimize based on single-thread execution assumption.
Opposite opinion is that JMM prohibits such an optimization because methods containing the loop(s) are synchronized.

gnat wrote:
...so that it will execute like this:
class NonVolatileConditionInLoopHacked {
private int number;
private boolean writingReady = true; // non-volatile, always handled inside synchronized block
public synchronized void setNumber(int n) {
if (!writingReady) { // moved out of loop condition
while (true) {
try { wait(); }
catch (InterruptedException e) { e.printStackTrace(); }
this.number = n;
this.writingReady = false;
notifyAll();
public synchronized int getNumber() {
if (writingReady) { // moved out of loop condition
while (true) {
try { wait(); }
catch (InterruptedException e) { e.printStackTrace(); }
this.writingReady = true;
notifyAll();
return number;
This question was recently discussed in [one of threads|http://forums.sun.com/thread.jspa?messageID=11001801#11001801|thread] at New To Java forum.
My take on it is that optimization like above is legal. From the perspective of single-threaded program, repeated checks for writingReady are redundant because it is not modified within the loop. As far as I understand, unless explicitly forced by volatile modifier (and in our case it is not), optimizing compiler "has a right" to optimize based on single-thread execution assumption.
Opposite opinion is that JMM prohibits such an optimization because methods containing the loop(s) are synchronized.One of the problems with wait() and your the proposed optimization is that "interrupts and spurious wakeups are possible" from wait() . See [http://java.sun.com/javase/6/docs/api/java/lang/Object.html#wait()] Therefore your wait() would loop without checking if this optimization would occur and a interrupt or spurious wake-up happened. Therefore for this reason I do not believe writingReady would be rolled out of the loop. Also the code isn't even equivalent. Once all the threads wake-up due to the notifyAll() they would spin in the while(true) and wait() again. I don't think the JMM prohibits such an optimization because methods containing the loop(s) are synchronized, but because it contains a wait(). The wait() is kind of a temporary flow control escape out of the loop.
Example:
writingReady is true
Thread A calls getNumber(). It waits().
Thread B calls setNumber(). It calls notifyAll() and writingReady is now false;
Thread A wakes up in getNumber() and while(true) loop and waits again(). //Big problem.

Using non-original RAM in X4600

Hi @all,
did anybody tried to use non-original RAM for a X4600? We are thinking to do so, because the RAM is a little bit expensive and we have an offer for the same typ of RAM from a local vendor for 1/4 of the SUN price. Anybody have any experiences?
Thanks in advance
Andr�

Normally, as with all other manufacturers, there could be warranty issues when using 3rd party RAM. Contact Sun.

IF YOU HAVE PROBLEMS WITH INSTALLATION ERRORS, REMOVE YOUR NON FACTORY RAM

I was having all kinds of errors with the installation of 10.5, I read about removing non factory ram. I did this and the installation worked just fine with no errors.
Except now I have a new problem where it won't recognize my user name and password. Apple has a post on how to correct this problem. I have done what they said and it does now work.
Now I am on the phone support hold line.....

polatfromfairfax wrote:
my friend, I hate to do this; all the possible variables are eliminated..if you really pay attention to my main point,
Mh friend, forgive me for asking something you didn't mention, "just to be sure."
it is high time for everyone to accept that this is not a end-user error...this is simply a firmware issue Apple engineers choose to ignore
Posting here is extremely unlikely to get Apple's attention.
Have you reported it? To an Apple Store, AppleCare, a Bug Report, or the Feedback site? If not, please do so. See Reporting a Problem to Apple if you're not sure how.

Mixing ECC and NECC (Non-ECC) RAM Modules

Hi,
I have a G5 Dual Core 2.0 with a pair of 512Mb Non-ECC (NECC) RAM installed and I want to upgrade to 3Gb. I'm thinking of getting 2Gb ECC modules and discarding the 1Mb NECC installed. But I came across a phrase in the Apple Manual of my G5 that states "DO NOT MIX ECC and NON-ECC Memory Modules WITHIN A PAIR." Does that mean I can mix ECC and NECC within Memory Banks and NOT within a PAIR? Because in that case I won't have to discard my NECC 1Gb and have a mixed 3Gb Memory!? I'm afraid to actually try it so I would appreciate your insights. Thanks much.
G5 Dual Core 2.0 Mac OS X (10.4.7)

Yes. You can mix ECC and nonECC as long as you don't pair the ECC with the nonECC. The computer will just treat all RAM as nonECC.
You can keep the original memory as long as the two 512MB DIMMs are always paired with each other.

Having Problems with Powerbook After installing New(non-apple) ram

I had a total of 768 mb of ram on my Powerbook G4 1.5 but I decided that I wanted to max it out to 1.25 gb. So I went out to the store and bought a used but tested 1gb Patriot ram chip to replace my 512mb . I put it in and went to system info to see if my computer detected it, and it did, it reported that I had 1.25gb just as I wanted. The next morning I was excited about using my newly upgraded computer ( I left it in sleep all night I don't know if that could have caused any problems) and when i turned it on first thing i got was that semi-transparent shut down your computer screen when OSX has experienced a problem, I had never seen this error message before, I can tell you I was pretty angry. I restarted my powerbook and then I logged in, I used Onyx and forced to run maintenance, thinking that might help, but again the comp crashed when i tried to open Onyx. and then again the next time trying to open Entourage, then AGAIN the next time trying to open Safari. What is going ON!? Now I am on my laptop again but i took out the 1gb and put back in my apple 512mb, so far so good but why did my 1gb not work?? I would like to have 1.25gb so ANY suggestions would be greatly appreciated.
Thanks, Eric

Acctually yes it was returnable and I did return it. But before i saw your comment I bought a new not pre-owned chip of the same kind, it also didnt work so I will take your advice and purchase a chip that supports bus slewing, maybe i'll go for the more expensive ones just for some added security
By the way thanks for the help,
Eric

MacBook Pro 13" (2012) non-retina ram upgrade.

Will upgrading my MBP 13" from 4GB to 8GB will make a big difference ?
MBP does get slow at times and i do tend to use 4+ apps most the time.
Will it boost my boot up time too ?

Adding RAM only makes it possible to run more programs concurrently. It doesn't speed up the computer nor make games run faster. What it can do is prevent the system from having to use disk-based VM when it runs out of RAM because you are trying to run too many applications concurrently or using applications that are extremely RAM dependent. It will improve the performance of applications that run mostly in RAM or when loading programs.
Does it help to have more RAM? Usually, "yes", if you are running out of RAM during use. You may find that the computer seems faster, but this is because memory shortage is bogging things down.
Using Activity Monitor to read System Memory & determine how much RAM is used
OS X Mavericks- About Activity Monitor
Understanding top output in the Terminal
The amount of available RAM for applications is the sum of Free RAM and Inactive RAM. This will change as applications are opened and closed or change from active to inactive status. The Swap figure represents an estimate of the total amount of swap space required for VM if used, but does not necessarily indicate the actual size of the existing swap file. If you are really in need of more RAM that would be indicated by how frequently the system uses VM. If you open the Terminal and run the top command at the prompt you will find information reported on Pageins () and Pageouts (). Pageouts () is the important figure. If the value in the parentheses is 0 (zero) then OS X is not making instantaneous use of VM which means you have adequate physical RAM for the system with the applications you have loaded. If the figure in parentheses is running positive and your hard drive is constantly being used (thrashing) then you need more physical RAM.

Anyone using non Apple ram with standard heatspreaders?

Hi,
Is anyone using non standard Apple ram with normal sized heatsink/heatspreaders and if so have you had any problems?
I can find ram for the same spec that works but they only have the standard thin silver heatspreader attached and am concerned about running temps etc.
If anyones using these modules without problems, please post here!
Thanks.

Might want to read this article and it has some good information to help you decide.

RT target works OK in volatile mode but does not when deployed in non-volatile mode.

I have developed several applications using the NI cRIO-9073 Integrated chassis. The applications work perfectly well in volatile mode (development), but when I come to deploy the the RT target as an executable the application does not work. Now, I ran the LabVIEW Real-Time 1 Solution application and the same problem occured, in this case, the USER1 LED came on then went off as if an error occured. I finally trapped an error around the shutdown stage, attached, funny thing is though the error code doe not make sense as I am not using the FPGA, running in scan mode, however, I could be missing something.
(Note: I have obviously modified the Real-Time 1 course solution to use my existing hardware)
Now this is where it gets puzzling, 3 years ago I did the old RT course, LabVIEW Real-Time Application Development, I have now run the solution for this course, on the same target as the RT1 solution and it works!!!
I have contacted NI support with no solution to this problem. In the meatime I have a NI cRIO-9704 on order and when it arrives I will try again.
I really need to know, however what is going on here, does anyone out there have any Ideas? have you experienced any similar problems?
Thanks
Neil

Note to self - Include attachment...
Error Log
Status: TRUE
Code: -65589
Source: Shared Variable in Chamber Control.vi->RT Main.vi
This error or warning occurred while reading the following Shared Variable:
\\NI-cRIO9073-0180F3D1\Thermocouple Mod\Temperature-cRIO
\\localhost\Thermocouple Mod\Temperature-cRIO
Error -65589 occurred at an unidentified location
Possible reason(s):
CompactRIO: The FPGA VI you are running does not contain the DMA FIFOs that the RIO Scan Interface requires. Ensure that the modules under the Chassis item in the project match the modules in the chassis, and recompile the FPGA VI.

Non-conforming RAM

I'm wondering if I can use 2 RAM sticks from a 2010 iMac in a Late 2012 machine - it's easy to try and I might experiment with this just for the heck of it.
The only difference in the spec is speed -
1333 MHz (2010)
vs
1600 MHz (2012)
The machine I'd like to try this on currently has 16GB (2x8) with 2 open slots.

is it really worth the risk?
Thank you for the reply!
Therein lies the question - what risk? Real - or merely perceived, for not staying between the lines? Now, if there was evidence that slower RAM could cause the computer to start on fire, well, we wouldn't try it right? :-)
Thanks for the referrals too however I wouldn't use a high end reseller, and certainly not ask them because their job is to SELL memory, not help people avoid buying more. Amazon, Ebay and others are far more cost effective paths to purchase RAM without excessive markups - and many RAM manufacturers these days offer lifetime warranty.
Anyway, I'll probably just sell the old RAM and buy the extra 1600MHz sticks when I need them - for now it's not something that's urgent so I was just toying with this idea.

[Solved] MSi GT60 Dominator (non-3K) - RAM Slots

Anyone knows where the primary RAM slot is located ? I'm want to replace the stock 8G Kingston RAM with a 16G Corsair Vengence which i already own. I can only see 2 empty slots when i open the bottom lid.

Quote from: Pegasus;104527
2 are under the keybaord and 2 under the notebook.
Same for all GT70 and GT60, doesn't mate 0NC, 2OE, 2PC, etc
If you want, you can see this video I made before, in french but with the video himself are already enought
https://www.youtube.com/watch?v=UcET1Vn-Qhk
Thanks Pegasus will check this out

Upgrading iMac to "non-apple" RAM, against applecare warranty?

Does anyone have some clarity on this issue? I want to upgrade my 2GB RAM to 4GB, will this default my warranty?
Thank you.

I believe you are asking if installing memory not purchased from Apple will invalidate your computer's warranty? As long as you install memory that meets the computer's memory specifications then you should be fine. Memory is the only thing Apply suggests users can install on their own.

Non-Detected RAM

I've got a 1.8 Dual G5 with 4x256MB RAM Modules already inside. If I move the pairs around the computer will not restart. I also purchased 2x1GB RAM Modules to upgrade the machine. If I put those in the machine w/out moving the others around it will start, but not detect.
What am I doing wrong?

When changing RAM configuration, in order for the memory to be seen and register properly, I've found that nvram needs to be cleared in order for the device tree to be rebuilt properly. Either zap PRAM/NVRAM from cold boot, or reset-nvram from Open Firmware (command option of).
Sometimes A brand and B brand don't get along, so test with just the new RAM as well. I'd put the 1GB DIMMs in first, see if it works, then the 4 x 256.
Run Apple Hardware Test and Memtest if you want to be sure. Memtest is easy to run with Applejack custom install (readme that comes with it).
Link to vendor these came from? DDR400 PC3200?

Inactive RAM (yes I know what it does)

My question is how Inactive RAM is reported once it has been used by the system. Here is what is happening to me. I sometimes there will be a spike in my RAM used and when I look at the activity I will see that there is about 200-250mb of Inactive RAM but my computer will slow to a crawl like it is out of RAM. I understand Inactive RAM is not currently being used and is supposed to be released when needed by other programs but when it is released should it shift to Active RAM? So should I see my Inactive RAM go down and my Active RAM go up? Or does the Inactive RAM just stay the same even though it is being used by the system.

The following may not directly answer your question, but it should help you better understand how memory management works in OS X.
About OS X Memory Management and Usage
Reading system memory usage in Activity Monitor
Memory Management in Mac OS X
Performance Guidelines- Memory Management in Mac OS X
A detailed look at memory usage in OS X
Understanding top output in the Terminal
The amount of available RAM for applications is the sum of Free RAM and Inactive RAM. This will change as applications are opened and closed or change from active to inactive status. The Swap figure represents an estimate of the total amount of swap space required for VM if used, but does not necessarily indicate the actual size of the existing swap file. If you are really in need of more RAM that would be indicated by how frequently the system uses VM. If you open the Terminal and run the top command at the prompt you will find information reported on Pageins () and Pageouts (). Pageouts () is the important figure. If the value in the parentheses is 0 (zero) then OS X is not making instantaneous use of VM which means you have adequate physical RAM for the system with the applications you have loaded. If the figure in parentheses is running positive and your hard drive is constantly being used (thrashing) then you need more physical RAM.

Resetting PMU, PRAM, etc when installing new RAM?

Dear Forum,
I've just ordered Kingston DDR SDRAM - KTA-G5400/2G 2GB PC3200 Kit - for my G5 Dual. My machine has 8 slots. This new RAM will occupy slots 4 and 5. I've checked that this is definitely the correct RAM for my machine.
I've read what Samara and Japamac have to say about resetting PMU,PRAM, and NVRAM.
Can you elaborate on this please? Where is the reset button located for my G5 Dual Processor? Is the reset performed before or after the installation of new RAM? The .pdf RAM installation manual (downloaded from this forum)does not mention any necessity to perform a reset, and does not identify the location of any button either?

Go to System Preference control panel Startup Disk and set it.
I'd use Option key to look for your boot drive first time anyway.
NVRAM
Non-volatile random access memory (NVRAM) is the general name used to...
http://en.wikipedia.org/wiki/NVRAM
PRAM: Parameter RAM, a small amount of NVRAM used on Apple Macintosh machines to store configuration information
http://docs.info.apple.com/article.html?artnum=2238
http://www.geocities.com/texas_macman/pram.html
http://www.felipecruz.com/reset-pmu-and-non-volatile-ram-g5.php
... there is a huge at-your-fingertips dictionary-encyclopedia-reference online and a click away...

True non-volatile ram - Yes or No?

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