An Interesting Power Point On Persistant Storage

[Jon Westfall]

<div class='os_post_top_link'><a href='http://blogs.msdn.com/windowsmobile/archive/2005/07/14/438991.aspx' target='_blank'>http://blogs.msdn.com/windowsmobile.../14/438991.aspx</a><br /><br /></div><i>"Remember that RAM requires power to keep its data. The amount of power needed is linear with the amount of RAM. That is to say, 64M of RAM needs twice as much power to keep it running as 32M does. 128M needs four times as much power as 32, etc. And this power drain is constant. The RAM is sucking your batteries dry while the device is in use and while it's suspended. It even continues to drain your batteries when they are "critically low" and the system won't let you turn it on. Also, people didn't buy 128M RAM devices for the program space. They bought them to store stuff in. And those devices had lousy battery lives as a result."</i><br /><br />Robert Levy dropped us a note with this post from Mike Calligaro in the Windows Mobile Team Blog. Persistant storage has always sounded nice to me, but after reading this post, it hammers home the point that it really will change the way we use our devices. I never appreciated how much my battery was monopolized by RAM (If I had really thought about it, I probably would have realized this, but like I said, this post hammered home the point to me in a way I hadn't really thought to think of ;) ). For all of you who are still skeptical about Persistant Storage in WM 2005, take a read through. And if you think you know why all the hype is warrented and welcome PS, take a read as well - it may make you think more than you had!

[Menneisyys]

Interestingly, the guy doesn't say anything on the write optimizations/caching (http://www.pocketpcthoughts.com/forums/viewtopic.php?t=41365&amp;postdays=0&amp;postorder=asc&amp;start=10) at all.

[shk718]

i just bought the samsung i730. the battery life sucks!!!! but it looks like it was designed for WM5 - so the question of the day is how do we force Verizon to give us an upgrade??

[Dalantech]

I was wondering if batter life would improve since you don't have to "feed" RAM when the device is turned off. I'm starting to see why Dell opted for a 1100 MaH battery in the Axim x50v -they probably designed it for WM 5...

[surur]

A a 128Mb ram device owner, currently using 46Mb for execution without any web pages open, I think 64Mb ram will continue to be limiting. When I upgrade my Loox 720 to WM5, I will benefit in two ways.

1) The artificial low battery restriction will have been removed, allowing me to get full benefit from my 1640mAh battery.
2) I will still have persistent storage.
3) I will be immune from future growth of software size, as I will always have more ram than most, meaning I can do much more at the same time.

The downside is that I use 10% of my battery capacity per day to keep my 128Mb ram alive, but my OEM provided a large 1640 battery to take account of this. I will continue looking for 128Mb ram in any device I buy, because I want more than I need in day to day use, not just enough.

Surur

[jngold_me]

Am I correct in understanding that WM5 will still allow a "suspend" mode for keeping state, similiar to what we have today?

Menneisyys,

Are these optimizations you speak of in the realm of the OS and are transparent to application developers, or will app developers need to adhere to certain programming methods to work "well" in the WM5 platform?

TIA!

Surur,

At this present moment I have a VB database app open, World Offline, and the full home page for CNN loaded in memory (in addition to various Today screen plugins) and I have 22.46mb in use. The only thing I can think of as to why your are using so much memory is VGA vs QVGA. I still find it hard to believe that such a disparity in memory usuage exists between the two (although stranger things do occur). :)

[Menneisyys]

Menneisyys,

Are these optimizations you speak of in the realm of the OS and are transparent to application developers, or will app developers need to adhere to certain programming methods to work "well" in the WM5 platform?


Dunno. There're only few apps (PIE, Netfront, SimpleSMS etc.) that do mass writing to the cache directory/database file. Therefore, most 3rd-party apps will work OK in WM5, at least speed-wise, without touching them.

I don't know whether the developers of WM5 have gone for the less resource-friendly, but certainly more compatible 'transparent ' mode, or, do they enforce the programmer to do some work instead (for example, instead of creating one file for each Web page resource (GIF's, JPG's, JavaScript files, CSS files and the main HTML page) - file creation speed sucks even more in the File Store than file writing speed - , concatenate their contents to just one file.) Both are possible.

[Phillip Dyson]

Why is it none of the "official" will answer questions about the lifecycle of ROM memory once everything starts to be written to it?

[Menneisyys]

Why is it none of the "official" will answer questions about the lifecycle of ROM memory once everything starts to be written to it?

Well, this question has been partly answered by HP's not providing the WM5 upgrade for the iPAQ rx3xxx (the worst PDA, file store life expectancy-wise) :devilboy:

I'm also afraid of the upgrade because of this fact. I'll try to find ways of relocating the Registry and the WinCE databases (especially if there will be a lot of PC -> PDA, for example, mail synchronization) back to the main memory, I think... My PIE/Netfront cache will also go back to the main memory. I don't want to have a paperweight (my PL720's warranty will run off this Autumn...)

[CESkins]

Downsides? Yes, nothing is free. Flash is much slower than RAM. Reading and writing large amounts of data will take longer on a PS device than it did on a RAM device. That initial sync that pulls down 400 contacts and 5000 emails will take longer. Some write operations will seem a bit more sluggish

The above quote is the reason why despite the gains in battery life, the new move towards persistant storage in the form of FLASH ROM does not excite me. I use Textmaker, PlanMaker, and ListPro (with several ~ 1 MB databases). Textmaker &amp; PlanMaker take a relatively long time to load/run when stored in FLASH ROM (or even an SD card) than RAM. ListPro also takes longer to open, search, and store large databases when they are stored in ROM. Since I use these apps frequently (especially ListPro) these delays can add up to a significant amount of time lost during the day. If newer devices come with faster FLASH ROM than currently in use or utilize a very good caching algorithm that may offset some of this slowdown.

Personally the reason I moved to a 128 MB RAM PDA (Loox 720) was for speed. Battery life was a moot point because I could charge my PDA anywhere (including the car while I drove using a retractable cable and multipurpose pocket adapter). Loosing my RAM contents was also rendered less of a nuisance/catastrophe by using automated backup software and storing mission critical data files on an SD/CF or File Store. My guess is that those of us who still want maximal speed when using their PDA will simply choose to leave certain apps like Textmaker running all the time rather than closing them to avoid slow reloads. Also to prevent having to reload the app, the PDA will never fully be turned off (thereby effectively closing running apps) during the working day. Since the RAM will always be in use, this renders the battery life savings gained by full power off moot (at least for me). The other advantages to persistant memory storage outlined in the article however will still hold true. From my standpoint, WM5 memory model appears to be a mixed bag.

Why is it none of the "official" will answer questions about the lifecycle of ROM memory once everything starts to be written to it?

It's finite (probably like SD and CF on the order of a few thousand writes). This will be one of the reasons to upgrade a relatively old device to a newer model. ;). My biggest fear is "loss" of the persistant storage. Some individuals reported their File Store simply disappeared and the system could not read from/write to it. The solution in some cases was to get a new PDA. If we start storing everything in one big file store, what's to say we won't end up loosing everything.

[signothefish]

While I agree that adding more RAM will consume more power (as you say, doubling it doubles the drain), in the overall scheme of things, memory represents only a fraction of all the parasites on your Pocket PC. The screen, backlight, WiFi, wireless communications, and microdrive are all very thirsty, which explains why I have to have the extended battery on my e800. That's why doubling, tripling, whatever the amount of memory on my device doesn't really bother me as much as it would others, because to me it's just a drop in the bucket.

To others who have a basic device or aren't power users (usually these are one and the same), which represent the majority of PDA owners, it would mean more to them. But then, most of them don't know any better anyhow, do they? All they care about is the fact that their battery is draining too fast so there must be something wrong with their PDA.

A large number of processes running on your Pocket PC will also drain your battery faster, such as a lot of today plugins and TSR programs. But instead of trying to find ways to make storage persistent, time would be better devoted to finding alternative power sources, because we're eventually going to need that gigabyte of memory on our devices + be able to handle these and future device "features".

[Jonathan1]

OK. If NOTHING else it will bring the system closer to acting like a desktop. Its not as if Windows 2000 allows you to store files in RAM. Well at least not without a RAMDisk.

I look forward to this transition because it should also free up much needed resources.

[surur]

In a similar thread I have demonstrated that its trivial to increase memory use to 75MB by simply loading two picture heavy web pages. Phone edition devices specifically start with a high number of processes running (one for listening for MMS, one to monitor GPRS use, one to display a caller picture, email monitoring etc etc) I am sure people with 64MB devices are going to see a lot of weird behaviour when software gets closed in the background to free up memory.

I'll be getting the MDA IV when it comes out, and am very glad that it will continue to come with a large amount of memory.

Surur

[Horus]

...in the overall scheme of things, memory represents only a fraction of all the parasites on your Pocket PC. The screen, backlight, WiFi, wireless communications, and microdrive are all very thirsty, which explains why I have to have the extended battery on my e800. That's why doubling, tripling, whatever the amount of memory on my device doesn't really bother me as much as it would others, because to me it's just a drop in the bucket.

This is correct if you think only of when the device is turned on, but remember that the power hit for RAM is constant whether on or suspended. So I would offer that over the lifetime of the device, the RAM refresh hit is actually much higher.
Also, of all aspects of mobile computing, power/battery is the one that is progressing the least quickly. This isn't due to lack of effort, because the rewards are great, it is just a matter of physics and engineering.
I think it is kind of funny that some of the responses seem to actually be defending the idea that a Pocket PC should lose everything if the battery fails. Personally, I've always found that inexcusable and I'll be glad to see that gone! ;-)

[Horus]

In a similar thread I have demonstrated that its trivial to increase memory use to 75MB by simply loading two picture heavy web pages. Phone edition devices specifically start with a high number of processes running (one for listening for MMS, one to monitor GPRS use, one to display a caller picture, email monitoring etc etc) I am sure people with 64MB devices are going to see a lot of weird behaviour when software gets closed in the background to free up memory.

You shouldn't see any weird behavior when background apps get closed. When you go back to them, they SHOULD return to the same state that they were in when you left them. Strangely enough, about the only major app I know of that doesn't follow the rules here is IE.

[Airscanner]

Is RAM really drawing that much battery? I would think the CPU is the big culprit...ARM based processors, for example, generate a ton of heat.

It sounds like there is a lot of room for some exciting innovation and improvement over the next few years.

Maybe it's time to go back to get that electrical engineering degree :)

[alex_kac]

Why is it none of the "official" will answer questions about the lifecycle of ROM memory once everything starts to be written to it?

Well, this question has been partly answered by HP's not providing the WM5 upgrade for the iPAQ rx3xxx (the worst PDA, file store life expectancy-wise) :devilboy:

I'm also afraid of the upgrade because of this fact. I'll try to find ways of relocating the Registry and the WinCE databases (especially if there will be a lot of PC -> PDA, for example, mail synchronization) back to the main memory, I think... My PIE/Netfront cache will also go back to the main memory. I don't want to have a paperweight (my PL720's warranty will run off this Autumn...)

Unfortunately you won't be able to do this. For one thing, the registry/databases all are being looked for at a certain path. The best you can do is make a RAM disk and copy non-system databases/files there if the apps allow that.


One thing that people don't realize is that any app built for WM5 will most likely do some buffering. Buffering minimizes the file read/write speed issues of the persistent store. Most apps read/write files byte by byte or section by section. If you do that on WM5, you will be terribly slow. If you buffer read/write operations with an 8k to 64k buffer, then the speed difference will be negligible, and may even be faster than the previous WM2003 release (of course the WM2003 release would then benefit as well).

[surur]

In a similar thread I have demonstrated that its trivial to increase memory use to 75MB by simply loading two picture heavy web pages. Phone edition devices specifically start with a high number of processes running (one for listening for MMS, one to monitor GPRS use, one to display a caller picture, email monitoring etc etc) I am sure people with 64MB devices are going to see a lot of weird behaviour when software gets closed in the background to free up memory.

You shouldn't see any weird behavior when background apps get closed. When you go back to them, they SHOULD return to the same state that they were in when you left them. Strangely enough, about the only major app I know of that doesn't follow the rules here is IE.

Apps like the one listening for MMS messages. If they close then you don't get your message. Or a GPS program that suddenly shuts down for no reason. It makes your PPC appear less reliable.

Surur

[thunderbass]

I?m still not convinced. Here?s why:

I?ve never lost my data due to a dead battery, and I use my Pocket PC a lot.

If I ever did loose my data due to a dead battery, since I sync with my desktop, usually two or more times a day, my data is backed up on a regular basis.

Something that greatly concerns me, and should concern most corporate users, is that if my pocket PC should ever all into the wrong hands, I?m secure in the knowledge that when someone does a hard-reset, all of my data will be gone. Please, someone correct me if I?m wrong, but if this should happen with WM5, after someone did a hard-reset to gain access to my device, my sensitive data would still be there for them to use. Even if I encrypt my data, they still have something to hack. Am I wrong? (I really hope so).

We?ve always had this sort of storage since the beginning, in the form of memory cards. In previous versions, we had a choice of using ROM or RAM, now we don?t.

Am I missing the something?

Thanks

[Menneisyys]

Something that greatly concerns me, and should concern most corporate users, is that if my pocket PC should ever all into the wrong hands, I?m secure in the knowledge that when someone does a hard-reset, all of my data will be gone. Please, someone correct me if I?m wrong, but if this should happen with WM5, after someone did a hard-reset to gain access to my device, my sensitive data would still be there for them to use. Even if I encrypt my data, they still have something to hack. Am I wrong? (I really hope so).

If you use strong compression (and I'm pretty sure that most 'corporate' PDAs will by default have it, just like the hx2750 now; even if the WM5 by default won't have built-in encryption) - a process that automatically de/encrypts everything -, then, I don't think anyone will have access to your WinCE databases storing your stuff.

[Horus]

Apps like the one listening for MMS messages. If they close then you don't get your message. Or a GPS program that suddenly shuts down for no reason. It makes your PPC appear less reliable.

Surur

If something depends on staying running all the time - it should be a service, not an app. Plus, in WM5, the State and Notification Broker will help with a lot of these cases - without requiring a service.
As for the GPS app, I can just restate what I said that a properly behaved Pocket PC app returns to its previous state if it is restarted after being closed by the system. The only thing you would notice is that there is a delay to reload the app instead of just switching to it.

[ipaqgeek]

Is RAM really drawing that much battery? I would think the CPU is the big culprit...ARM based processors, for example, generate a ton of heat.

It sounds like there is a lot of room for some exciting innovation and improvement over the next few years.

Maybe it's time to go back to get that electrical engineering degree :)
Yes, RAM draws a lot of power because it stores memory in a leaky capacitor. Why is it leaky? Because it's cheap. You wan't RAM that isn't leaky? It's called SRAM (a completely different technology), and it's super expensive (per bit) compared to RAM.

Most of the memory innovation and improvement that can be made in the next few years is not with the devices, it's with manufacturing processes. There's already tons of RAM alternatives (FRAM, MRAM, OUM Ram, etc) using totally new and different technologies, but again: expensive. Prices are coming down as they develop better materials and processes, but most of these technologies still won't be competitive with RAM for another 5-10 years, maybe more (the date keeps getting pushed out as RAM continues to get cheaper).

I personally suggested something I called Core-dump Flash RAM a while ago, that would have all the benefits of RAM and Flash combined - but it was met with widespread skepticism. It would require a new kind of Flash memory using the standard Flash unit cell where all the periphery was replaced with super massively parralel multiplexing circuits to cache a core-dump of up to 1GB from the RAM within seconds - this allows you to instantaneously do a suspend while completely turning off the RAM. It could be done, and it's uses could transform the handheld industry, but the idea seemed to just make everyone grumpy.

[Dalantech]

I think a lot of you may be missing the point: If there is a suspend mode then you'll be writing the contents of RAM to the hard drive -there will not be any power going to RAM once you shut the PDA down...

I routinely surf the web with only 16MB of program RAM free with no problems, so were are these "weird program errors" going to come from if I have nearly all of the 64MB of RAM in my x50v to run applications?...

Last, but not least, storing data and applications won't be limited to the ROM built into the device: I'll be able to use CF and SD for data storage. Both are a lot faster than the ROM built into my Axim...

[surur]

I routinely surf the web with only 16MB of program RAM free with no problems, so were are these "weird program errors" going to come from if I have nearly all of the 64MB of RAM in my x50v to run applications?...


Try loading this page with 16Mb free. (BTW it works fine on my loox 720).

http://forums.fark.com/cgi/fark/comments.pl?IDLink=1569355

Surur

[Paragon]

Something that greatly concerns me, and should concern most corporate users, is that if my pocket PC should ever all into the wrong hands, I?m secure in the knowledge that when someone does a hard-reset, all of my data will be gone. Please, someone correct me if I?m wrong, but if this should happen with WM5, after someone did a hard-reset to gain access to my device, my sensitive data would still be there for them to use. Even if I encrypt my data, they still have something to hack. Am I wrong? (I really hope so).

We?ve always had this sort of storage since the beginning, in the form of memory cards. In previous versions, we had a choice of using ROM or RAM, now we don?t.

Am I missing the something?

Thanks

One feature of Exchange, which many corporate people use, is that you can remotely wipe your device clean if you should loose it. You don't have to wait for someone else to do it for you. ;)

Dave

[WyattEarp]

Since WM5 will use FlashROM (PS) to store all programs then manufactures will need to start making devices with more memory real soon. I have 94MB worth of software on my PPC alone (exluding games which I keep on SD card). So what are people like me to do? The X50v and hx4700 are the ones I like the most but neither of them have a big enough FileStore and giving up software is not an option. So with WM5 just around the corner it seems like a step backwards instead of forwards when it comes to memory. I have always hated advertising of the amount of memory in PPCs and its not the amount you get to use. I hope that it does change.

[mmidgley]

I think RAM and Flash are both important, and I want plenty of both. I still use an iPAQ 5555 despite the fact that its stuck at WM2003--its 128MB RAM/48 MB Flash is a big reason I have kept it.

I want RAM for program storage/execution and data storage space. RAM may take battery to refresh, but its fast! I want Flash for program and data storage. Currently I backup to a 512 MB SD card. It would be nice to have 128 or 256 MB RAM (yes, with a BIG battery) and 512+ MB flash on a device--that way it could "mirror" the system RAM to Flash while the PocketPC is "idle". That way a backup to SD card would be: wait for RAM to flash sync, and then simply copy to SD card.

Many devices have slow built-in ROM--they could spend a bit more and put faster Flash in, and maybe oem's will start to do that, but they haven't in the past. With fast flash and RAM memory we will start to take advantage of these fast processors.

m.

[ipaqgeek]

Since WM5 will use FlashROM (PS) to store all programs then manufactures will need to start making devices with more memory real soon. I have 94MB worth of software on my PPC alone (exluding games which I keep on SD card). So what are people like me to do? The X50v and hx4700 are the ones I like the most but neither of them have a big enough FileStore and giving up software is not an option. So with WM5 just around the corner it seems like a step backwards instead of forwards when it comes to memory. I have always hated advertising of the amount of memory in PPCs and its not the amount you get to use. I hope that it does change.

Right now you can store many if not most of your programs on an external Flash card if you want to and if you know what you are doing (it's kind of tricky with some programs). Are they going to remove that capability with WM5?

[Paragon]

Are they going to remove that capability with WM5?

No, you will still be able to install applications to a storage card.

[ipaqgeek]

I just with they'd hurry up and develop miniature fuel cells for handhelds, and have fuel dispensing machines on every corner. Then we wouldn't have to worry about battery life - just remember to add an ounce every couple days.

[ipaqgeek]

Are they going to remove that capability with WM5?

No, you will still be able to install applications to a storage card.
That's what I thought. I think most people don't know that you can do that so the new memory scheme really gets them all worked up.

[WyattEarp]

Since WM5 will use FlashROM (PS) to store all programs then manufactures will need to start making devices with more memory real soon. I have 94MB worth of software on my PPC alone (exluding games which I keep on SD card). So what are people like me to do? The X50v and hx4700 are the ones I like the most but neither of them have a big enough FileStore and giving up software is not an option. So with WM5 just around the corner it seems like a step backwards instead of forwards when it comes to memory. I have always hated advertising of the amount of memory in PPCs and its not the amount you get to use. I hope that it does change.

Right now you can store many if not most of your programs on an external Flash card if you want to and if you know what you are doing (it's kind of tricky with some programs). Are they going to remove that capability with WM5?

I only keep games and documents on an SD card which stays in my PPC. Programs I need to keep on the PPC itself. I use my device alot between personal and business life and it's not convenient to keep programs on SD cards. I still use my 5555 because of the amount of memory it has. I would love to have a PPC with a VGA screen but none of them fit my memory requirements. That's very disappointing to me. With every new PPC made we make trade offs instead of adding to already good designs and that's what I don't understand or like having to do. Call me picky but that's how I see it.

[Dalantech]

I routinely surf the web with only 16MB of program RAM free with no problems, so were are these "weird program errors" going to come from if I have nearly all of the 64MB of RAM in my x50v to run applications?...


Try loading this page with 16Mb free. (BTW it works fine on my loox 720).

http://forums.fark.com/cgi/fark/comments.pl?IDLink=1569355

Surur

I'm replying to this post om my Axim.. So, what's supposed to happen -every thing is working just fine... :roll:

[surur]

I routinely surf the web with only 16MB of program RAM free with no problems, so were are these "weird program errors" going to come from if I have nearly all of the 64MB of RAM in my x50v to run applications?...


Try loading this page with 16Mb free. (BTW it works fine on my loox 720).

http://forums.fark.com/cgi/fark/comments.pl?IDLink=1569355

Surur

I'm replying to this post om my Axim.. So, what's supposed to happen -every thing is working just fine... :roll:

You must be joking! That page is at least 23MB big when loaded. I did not say with images off.

Surur

[Dalantech]

I routinely surf the web with only 16MB of program RAM free with no problems, so were are these "weird program errors" going to come from if I have nearly all of the 64MB of RAM in my x50v to run applications?...


Try loading this page with 16Mb free. (BTW it works fine on my loox 720).

http://forums.fark.com/cgi/fark/comments.pl?IDLink=1569355

Surur

I'm replying to this post om my Axim.. So, what's supposed to happen -every thing is working just fine... :roll:

You must be joking! That page is at least 23MB big when loaded. I did not say with images off.

Surur

I think the first time I hit the page I didn't let it finish loading -you're right, it tanked :(

However with WM5 it won't matter since all of the 64MB of RAM that I have will be available for applications. Even now I could load that page if I didn't use RAM for application storage.

IMHO RAM won't be a problem, but batteries will. Lithium Ion batteries are designed to be fully charged and frequently charged -they do not handle deep discharges well. If WM5 encourages people to fully discharge their batteries then we may see a higher instance of battery failure...

[Myrddin]

Apologies for posting to a slightly older news item, but I have a question. I install all my apps and and store all my documents on the "iPAQ File Store" area of my hx2750 ipaq..... does this, in a sense, mean I'm already working in the way WM5 expects everyone to work... also meaning that because my RAM is basically completely free... my battery life is slightly increased? Thanks.

[Darius Wey]

Apologies for posting to a slightly older news item, but I have a question. I install all my apps and and store all my documents on the "iPAQ File Store" area of my hx2750 ipaq..... does this, in a sense, mean I'm already working in the way WM5 expects everyone to work... also meaning that because my RAM is basically completely free... my battery life is slightly increased? Thanks.

You've got a similar idea going, but you're far from achieving the full effects of persistent storage. Your current device with WM2003SE means that half your RAM is still devoted to program execution, with the other half for storage. With Windows Mobile 5.0, you'll effectively free up all of that RAM for program execution. Also, given your current configuration, if you were to run your battery flat, your device would still revert back to its factory default (with program files still in your non-volatile ROM, but it doesn't necessarily mean you can run them, since most require added system files in the \Windows\ directory, which resides in RAM, as well as added registry keys). With Windows Mobile 5.0, that's not the case. Since nothing is stored in RAM, even if your RAM gets wiped with the battery flat, your system will remain untouched since all your data resides in ROM.

In short, nothing can replicate the persistent storage feature in Windows Mobile 5.0. You'll benefit greatly from the update when HP makes it available for your device.

[pocketpcadmirer]

this things looks gr8

[Myrddin]

Apologies for posting to a slightly older news item, but I have a question. I install all my apps and and store all my documents on the "iPAQ File Store" area of my hx2750 ipaq..... does this, in a sense, mean I'm already working in the way WM5 expects everyone to work... also meaning that because my RAM is basically completely free... my battery life is slightly increased? Thanks.

You've got a similar idea going, but you're far from achieving the full effects of persistent storage. Your current device with WM2003SE means that half your RAM is still devoted to program execution, with the other half for storage. With Windows Mobile 5.0, you'll effectively free up all of that RAM for program execution. Also, given your current configuration, if you were to run your battery flat, your device would still revert back to its factory default (with program files still in your non-volatile ROM, but it doesn't necessarily mean you can run them, since most require added system files in the \Windows\ directory, which resides in RAM, as well as added registry keys). With Windows Mobile 5.0, that's not the case. Since nothing is stored in RAM, even if your RAM gets wiped with the battery flat, your system will remain untouched since all your data resides in ROM.

In short, nothing can replicate the persistent storage feature in Windows Mobile 5.0. You'll benefit greatly from the update when HP makes it available for your device.

Thanks for the great answer Darius :)

However, the apps "installed' in my file store are actually just sitting there, they've survived a few hard resets and don't have their original registry entries/other files ... all work fine :D ... All I have is a set of shortcuts to copy into the start menu (also stored in file store) upon a hard reset to essentially restore my PPC to its setup state after a hard reset... hrm.... I guess I'm as close to the WM5 system as a I can be atm! Looking forward to the real thing! :D

[Darius Wey]

However, the apps "installed' in my file store are actually just sitting there, they've survived a few hard resets and don't have their original registry entries/other files ... all work fine :D ... All I have is a set of shortcuts to copy into the start menu (also stored in file store) upon a hard reset to essentially restore my PPC to its setup state after a hard reset... hrm.... I guess I'm as close to the WM5 system as a I can be atm! Looking forward to the real thing! :D

Probably not the best way to have programs "installed" on a freshly-hard reset system, but if it works for you, I guess go with whatever floats your boat. ;) :)

[Soyale]

I use Textmaker, PlanMaker, and ListPro (with several ~ 1 MB databases). Textmaker &amp; PlanMaker take a relatively long time to load/run when stored in FLASH ROM (or even an SD card) than RAM.

One of the benefits of the Windows Mobile development platform to a developer is the high degree of standardization we try to keep. Persistent store is a great example of such a technology, rather than making it optional for OEMs we have standardized Windows Mobile devices around it. The net of this is that longer term, developers can optimize to things to persistent store and be confident those optimizations are applicable to all in market devices. I'm confident over time apps like ListPro, PlanMaker etc will be optimized for persistent store and not suffer long load times.

An example of this type of optimization is the UU Encode and UU Decode algorithm in Outlook Mobile which initially ran very slowly. We discovered that it was reading the blocks to decode 3 bytes at a time from the file. Because file reads are somewhat slower by simply buffering the read we were able to achieve better performance.

[Soyale]

Something that greatly concerns me, and should concern most corporate users, is that if my pocket PC should ever all into the wrong hands, I?m secure in the knowledge that when someone does a hard-reset, all of my data will be gone. Please, someone correct me if I?m wrong, but if this should happen with WM5, after someone did a hard-reset to gain access to my device, my sensitive data would still be there for them to use. Even if I encrypt my data, they still have something to hack. Am I wrong? (I really hope so).


A hard reset is still a hard reset. It will flush the file system and registry so your data would be wiped off the device.

[pharbrian]

I want to buy an Axim X50v. When I get the WM 5.0 upgrade in October, will that transform the device into a persistant storage device, or is that a hardware thing where I have to wait for a new device that has the proper hardware in it to have persistant storage?

[Darius Wey]

I want to buy an Axim X50v. When I get the WM 5.0 upgrade in October, will that transform the device into a persistant storage device, or is that a hardware thing where I have to wait for a new device that has the proper hardware in it to have persistant storage?

No, all Windows Mobile 5.0 devices will be equiped with the persistent storage feature, so as soon as you apply the upgrade to your X50v, you're geared up with the new storage technology.

[Ce]

After reading many..many posts about WM 2005 persistant storage of people who know very well what they are talking about I still don't know what to do because a lot i've read was to "technical".

I'm in the proces of buying another VGA PPC. With WM2005 around the corner what is the better choice when it comes to memory setup:

128 Mb RAM and 64 Mb ROM (Loox 720)
or
64 Mb RAM and 128 Mb ROM (Dell X50v)

TIA!!

Carel

[surur]

When looked at purely from a memory point of view, the Dell setup is good, as having only 64MB RAM will lead to less battery drain, and 64Mb ram should be enough for most people. The 128Mb ROM should mean you can install more on the device directly, vs installing apps on a SD or CF card.

Its however less clear cut than that, because
a) the loox has a much bigger battery than the Axim (1640 vs 1100 mAh), so the slight increased battery drain is negated easily. In battery stress tests the Loox lasts longer than the Dell, despite the bigger drain from the battery, and it will continue to do so.
b) the 64MB extra ROM that the Axim has can be slower than a fast SD for installing apps, and 64 Mb SD cards are basically free.
c) In some extreme situations the 64Mb extra ram could come in very handy. If you have it you will be glad, if you don't you will be stuck. The same can not be said of an extra 64MB ROM.
d) The Loox has a number of other great advantages such as USB host, VOIP speaker, jog dial and better screen which is much more important that how the memory setup will change in WM 5.0 . Of course the Axim has a slightly faster processor (520 vs 624Mhz) and a very good 16Mb video accelerator which is getting increasing support from developers, and in America is MUCH cheaper.

In summary then, the memory changes are interesting, but not as important as the other issues as cost, support and features.

Surur

[Menneisyys]

Dunno if this quote has been discussed in the thread or not (don't have time to check it):

"A typical battery holds 1000mAh of charge. 128M of RAM takes about 500mAh to stay resident for 72 hours. 64M takes about 250. This is why you never saw a 256M WM 2003 device. It would have run for a minute then decided its batteries were critically low.” – He added."

This may have been true with early, third-party memory add-ons (for example, the iPAQ 3630 with an additional 32M RAM), but not with today's high-end 128M RAM PDA's.

For example, the Pocket Loox 720 (a 128M RAM device) only consumes some 100 mAh a day when suspended (this has been reported by several PL720 users). This means you can leave it unattended for even 2 weeks.