a pocket pc that keeps data forever - your opinion

[ronaldo]

hi,

in one of the last discussions it turned out that pocket pc's already exist with non-volatile memory such as the mpx or toshiba e75 with flash memory.

i.e., even despite your battery being empty all your data won't be lost but kept forever like with any ordinary desktop pc's/mac's etc.

however, it seems as if this "non-volatile technology" is much more expensive. on the other hand many years ago it was apple who brought out the very first pocket pc version called newton with the same technology but for the same price.

what do you think is the real reason why this technology is still in its infancy and costs so much more? are there any alternatives to flash ram technology? and finally what needs to be changed to make pocket pc's with non-volatile memory cost not more than other ordinary ones?

ronaldo :roll:

[surur]

There are a number of reasons why non-volatile memory is not used in the ppc world.

One of them is cost, with static ram being more expensive than dram. However there are other factors, such as the slow speed of static ram, and the limited write cycles that apply to static ram.

I believe all these problems are slowly being sorted out, and certainly the speed and cost have improved dramatically over the years.

Surur

[ppcsurfr]

In case you just missed it... Windows Powered Smartphones use this system where all data is stored in flash rom rather than in RAM.

Even if you take out the batteries, data is safely kept in the IPSM.

ASUS, Mitac, HTC (O2XDA II) all have extra ROM space... some of them use NOR flash for the OS and NAND Flash for the persistent storage.

I think this will show that it is no longer that expensive to implement such use of memory...

Mabuhay! ~ Carlo

[dh]

Nearly all the apps on my ancient Axim X5 live in the non-volatile "Built-in Storage". A great feature since I have to use very little precious RAM.

[ctmagnus]

But if there's a logon password-related issue, does the non-volatile RAM not get wiped also?

[Stephen Beesley]

There are a number of reasons why non-volatile memory is not used in the ppc world.

One of them is cost, with static ram being more expensive than dram. However there are other factors, such as the slow speed of static ram, and the limited write cycles that apply to static ram.

I believe all these problems are slowly being sorted out, and certainly the speed and cost have improved dramatically over the years.

Surur


I am suprised to hear that limited write cycles are a problem with static ram. There are still many thousands of Apple Newtons out there being used daily - some of which might have been in active service for well over 7 or 8 years (if you do not believe me check out the still very active NewtonTalk (http://www.newtontalk.net/) mailing list) and I have never heard of one failing for this reason. I am sure that one of these days the write cycle limit would come into action but I suspect that in real life the device would probably die form some other reason long before this factor would kick in. As for the other point about slower speed - that I will have to conceed :D - however I am sure this has improved over the years since the Newton was produced.

[GSmith]

There are a number of reasons why non-volatile memory is not used in the ppc world.

One of them is cost, with static ram being more expensive than dram. However there are other factors, such as the slow speed of static ram, and the limited write cycles that apply to static ram.

I believe all these problems are slowly being sorted out, and certainly the speed and cost have improved dramatically over the years.

Surur


I am suprised to hear that limited write cycles are a problem with static ram. There are still many thousands of Apple Newtons out there being used daily - some of which might have been in active service for well over 7 or 8 years (if you do not believe me check out the still very active NewtonTalk (http://www.newtontalk.net/) mailing list) and I have never heard of one failing for this reason. I am sure that one of these days the write cycle limit would come into action but I suspect that in real life the device would probably die form some other reason long before this factor would kick in. As for the other point about slower speed - that I will have to conceed :D - however I am sure this has improved over the years since the Newton was produced.

That is not quite right. Static RAM does not have limited write cycles. FLASH has limited write cycles.

Traditionally, static RAM has MUCH faster write times that FLASH (nanosecs vs. microseconds). This, combined with the limited write cycles of FLASH, made FLASH unsuitable for the main memory of PDAs. I am surprised to hear that the Newton can retain its memory without battery. One alternative has been battery-backed RAM where the RAM has its own battery (either inside the chip's packaging or external). But that battery would eventually fail (5-10 years retention are possible).

Alternative non-volatile possibilities are shadow ram and ferroelectric RAM. More info is at http://smithsonianchips.si.edu/ice/cd/MEM96/SEC11.pdf. Shadow RAM is relatively expensive and ferroelectric RAM is limited in size (32 MB available in 1H2004).

[Stephen Beesley]

...I am surprised to hear that the Newton can retain its memory without battery. One alternative has been battery-backed RAM where the RAM has its own battery (either inside the chip's packaging or external). But that battery would eventually fail (5-10 years retention are possible).

Alternative non-volatile possibilities are shadow ram and ferroelectric RAM. More info is at http://smithsonianchips.si.edu/ice/cd/MEM96/SEC11.pdf. Shadow RAM is relatively expensive and ferroelectric RAM is limited in size (32 MB available in 1H2004).

The last of the Newtons (the Message Pad 2100) had three different types of memory onboard: 8 MB of Mask ROM, 4 MB of DRAM, 4 MB of Flash RAM. The DRAM was system memory while the Flash RAM was user storage and would survive a loss of power. The only thing that you would loose without power was the clock setting. The earlier Newtons had a small backup battery (watch type) to preserve this while the MP2k and MP21k had an onboard capacitor for this job.

[GSmith]

My impression from the post was that non-volatile memory was being used for system memory. DRAM (volatile memory) makes sense. Thanks for clearing that up for me.

[Stephen Beesley]

My impression from the post was that non-volatile memory was being used for system memory. DRAM (volatile memory) makes sense. Thanks for clearing that up for me.

No worries :D

[ronaldo]

what does it depend on to implement such a technology into pocket pcs for a price that's not higher than ordinary ones?

is it really the manufacturing cost of the types of memory?
or is it more a question of demand by the market?
or is just a question of time till one of the pocket pc manufacturer is willing to market their products for a less higher margin (which in my view still seems to be extremely high compared to desktop pcs)

[Kati Compton]

Traditionally, static RAM has MUCH faster write times that FLASH (nanosecs vs. microseconds). This, combined with the limited write cycles of FLASH, made FLASH unsuitable for the main memory of PDAs. I am surprised to hear that the Newton can retain its memory without battery. One alternative has been battery-backed RAM where the RAM has its own battery (either inside the chip's packaging or external). But that battery would eventually fail (5-10 years retention are possible).

Alternative non-volatile possibilities are shadow ram and ferroelectric RAM. More info is at http://smithsonianchips.si.edu/ice/cd/MEM96/SEC11.pdf. Shadow RAM is relatively expensive and ferroelectric RAM is limited in size (32 MB available in 1H2004).
Just to supplement:

"static RAM" or SRAM is volatile. No power => no data. The difference between static and dynamic RAM is that dynamic RAM actually needs to be read and rewritten periodically (on the order of 10s of milliseconds I think) to keep its value (your computer does this automatically), wheras SRAM will just hold onto the value while it has power. This is one of the reasons SRAM is faster - you're not going to stall on a "refresh" while reading the RAM.

Now, on the other hand, there's the size of an individual memory cell. A single bit of dynamic memory is a single transistor and a capacitor. (basically, you store a value on the capacitor, and that degrades over time--which is why you have to refresh it). Static RAM on the other hand, is a pair of cross-coupled inverters plus 1-2 more transistors to control read/write behavior. Generally this leads to 5 or 6 transistors per bit.

This means that SRAM is significantly bigger than DRAM on a per-bit basis, which makes it more expensive (more silicon to get the same amount of storage).

The compromise computer systems make is that they use the faster but expensive SRAM as cache memory, and the cheaper but slower DRAM as main memory. Generally.

Anyway, that's why static RAM is called static RAM even though it is volatile.

Now back to your previously scheduled Flash RAM discussion.

[ronaldo]

quite interesting to hear the subtle but quite significant differences between static and dynamic memory.

but before it gets too technical i wonder if anybody could get down to the nitty-gritty also in the real world of money:

i.e. it would be quite interesting to have some ballpark figures as to how much these types of memory per mb really cost.

and maybe someone is also able to tell which types of memory (storage and volatile ram) eg. apples uses for its ipod.

:?:
ronaldo

[Wiggster]

and maybe someone is also able to tell which types of memory (storage and volatile ram) eg. apples uses for its ipod.

You mean for storing the files? Those multiple-gigabytes of storage? Hard drives. Check out the Tech Specs (http://www.apple.com/ipod/specs.html)

[ronaldo]

i've already checked the technical specs of apples' ipods - but they don't tell anything about the type of memory which is being used which is why i thought to find an answer here...

ronaldo :?

[ronaldo]

i've done a bit of research about apple's ipod components and found out that apple basically uses 3 types of memory:

- a hard drive like storage memory from toshiba ranging from 5gb to 40gb
- a 32 mb sdram from samsung
- a 1mb flash memory from sharp to store the system operating code

interestingly most of the time the storage memory is dormant as the processed information in fact comes from the sdram memory.

also interestingly i found that apart from the main processor (which is an arm processor, a portalplayer 5502) there is another chip from texas instruments:

this chip is being used as a firewire link and serves as both data and battery charging interface!



now what this all means in the end to the world of current and future pocket pc's (at least in humble opinion):


at the moment i feel that the market of current pocket pcs is a dead end - its technology especially with its flawed memory management needs serious improvement. i am not sure whether pocket pcs really need much more powerful processors to do the day-to-day work.

i rather believe that the future pocket pc will gear towards a blend of mobile phone, mp3 player and primarily data storage device. of course it would be nice to also watch or edit videos on pocket pcs. but apart from the huge data problem it is simply not practical due to the tiny size of the screen:

imagin, watching 3 hours "return of the king" with your friend in front of a 160 x 128 pixel screen!

there are much better and much cheaper solutions out there.

on the other hand apple has shown that it is possible to produce powerful but also practical handheld devices that are capable eg. of an improved memory management including storing huge data forever (even if the battery has gone) but which still cost well less than say a laptop.

of course, apple's ipod is not the end of the story - in my view it's just to prove that the world of pocket pc's could do much much better!

ronaldo
:|

[MLewis]

Even though I don't own one of those stylish iPod's, but the suggestions as outlined here really make sense. To me it looks as if Apple seems to be ahead in terms of technology. Manufacturers of PocketPCs would be better off to adapt certain ideas.

The vision of PocketPCs transforming into a hybrid of phone, music player and a computing device...Hmm, why not? Speaking for myself I might be even tempted to use such a device more often - as long as it can be guaranteed that, most importantly, all the data stored are being kept forever and not lost when the battery has run out of power!

[ronaldo]

>>as long as it can be guaranteed that, most importantly, all the data stored are being kept forever and not lost when the battery has run out of power!

being able to additionally play up to 8 hours of music non stop whilst having your data safely and forever stored in an internal 4 gb micro hard drive like in apple's ipod... sounds like a promotional text for apple, but it's just simple fact.

ronaldo