Author Topic: Why 64mb? (Read 5301 times)

iamasmith · « **on:** February 15, 2005, 04:34:48 pm »

It may be an over simplistic question but why do you think there's a dogged persistence with 64Mb as the standard offering with Zaurus models?

I don't think there's one Zaurus user on this forum that wouldn't want just that little more memory in their device and simply because the devices (mostly) are running Qtopia doesn't mean that memory demands necessarily diminish.

So what's the reason? I can only suspect that Sharp still think of the Z as a PDA (even though they term it Personal Mobile Tool) and however much sense it makes to give it more RAM there's just no overwhelming reason when other PDAs max at 64Mb?

I don't know, maybe there are other factors such as discreet devices that conveniently provide 64Mb in a small form factor. Budget for space on a PCB has got to be tight but I know that there are RAM upgrade offerings for some PocketPCs to go as high as 256Mb so it can't be beyond the realms of possibilities to expect more RAM in a Z.... I'm sure above anything else this is something that people would be willing to trade up to....

Thoughts??? (Come on kopsis I know you have some insider info here )

adf · « **Reply #1 on:** February 15, 2005, 04:45:31 pm »

and another thread was just started on harware repair /mods.... hmmmmm.

What about the htachi 6k clone? it has 128? possible to mod the 6k likewise maybe?

tumnus · « **Reply #2 on:** February 15, 2005, 06:32:38 pm »

More RAM means more power consumption. Since RAM is volatile, the RAM has to be constantly refreshed to keep everything in memory, even when suspended (in fact that's about the one thing that drains the battery when suspended). Doubling or quadrupling the RAM will have a significant impact on an already short battery life.

Curious Aardvark · « **Reply #3 on:** February 17, 2005, 02:10:22 pm »

but does the power drain still apply if you use a swapfile on a sd card to increase working ram ?
I haven't tried that yet but am thinking about setting swapfile up. But not if it's going to wear my z out - battery life at the moment is pretty amazing :-)

tumnus · « **Reply #4 on:** February 17, 2005, 04:12:13 pm »

It probably increases power consumption while using your zaurus with working memory that is larger than your available RAM as writing and reading to a flash card requires more power than writing and reading normal RAM. It's not going to doing anything bad to your battery though. If you stop using it, your battery life would go back up again.

iamasmith · « **Reply #5 on:** February 17, 2005, 04:28:32 pm »

Interesting, hadn't really considered DRAM refresh as a major drain on battery life.

I wonder if the PocketPC guys that had the PocketPCTechs 256Mb upgrade noticed anything... mind you I think they were also offering battery capacity upgrades too.

Maybe 64Mb does represent a good point for an 'average' user. I think the Zaurus is likely to attract anything but the average user though and think that most people would like to see the figure go up.... I suppose it's a problem of deciding where to stop 128Mb, 256Mb etc. etc. clearly a micro modular MM approach that allows the flexiblity to add RAM would use up too much real estate so I guess the next thing if people are routinely suffering because they are ending up swapping (and therefore using more juice anyway) is to have indispensible Qtopia apps that significantly benefit from extra memory to drive the need for a model with more RAM (from Sharp's perspective).... not such a good move on the software developers part (assuming it's commercial) though.

- Andy

speculatrix · « **Reply #6 on:** February 17, 2005, 05:56:17 pm »

Quote

Interesting, hadn't really considered DRAM refresh as a major drain on battery life.

the power use is due to the fact you have to strobe through all the rows in each DRAM device so that the DRAM chip can refresh the data - all those lines oscillating away drawing switching current to power their capacitors.

static ram has lower power consumption by far but is hugely expensive in comparison

swapping to flash memory is SLOW, flash is relatively fast to read but is slow to write unless there's internal buffers to give a short term intermediate store - the microdrive is a far better bet, doesn't "wear out" in the way flash does.

you can buy non-flash memory cards in CF format - try www.jactron.co.uk as a specialist supplier of all kinds of more interesting memory cards

I agree that Sharp are very short sighted to not have more memory - they could if they really wanted fit say 256MB, "lock" 128MB of that - write protect - for the OS and files, and leave 128MB for users, the locked 128MB could be unlocked temporarily for upgrades, and of course needs to be backable up.

ScottYelich · « **Reply #7 on:** February 17, 2005, 09:57:22 pm »

I haven't tested it... but I can get a 40x write (60x?) 1GB CF card for like $140.

I know my camera writes out 5megapixel pics fairly quickly.

Has anyone tested any of these faster Nx cards?

Scott

kahm · « **Reply #8 on:** February 17, 2005, 10:26:09 pm »

Quote

you can buy non-flash memory cards in CF format - try www.jactron.co.uk as a specialist supplier of all kinds of more interesting memory cards

[div align=\"right\"][a href=\"index.php?act=findpost&pid=67576\"][{POST_SNAPBACK}][/a][/div]

I spent a few minutes on that site, but I wasn't able to find non-flash CF cards. I only saw PCMCIA SRAM cards.

Do you have any other links that might have things like that? A RAM or SRAM CF card would be a very interesting toy indeed...

Oneiros · « **Reply #9 on:** April 27, 2005, 10:59:00 am »

And what about swapping on a usb key?

I don't know if it's totally stupid but as I 've got a spare 64 mb usb key and I keep reading that swapping on my 1G sd card will destroy it on the long run, I wanted to know if this would work on my C1000 and how to do it.

omega · « **Reply #10 on:** April 27, 2005, 01:57:24 pm »

Oneiros... should be possible. Mount the usb storage and format it as swap and then swap on.... look for instructions around here...

Oneiros · « **Reply #11 on:** April 27, 2005, 05:37:00 pm »

Quote

Oneiros... should be possible. Mount the usb storage and format it as swap and then swap on.... look for instructions around here...
[div align=\"right\"][a href=\"index.php?act=findpost&pid=77198\"][{POST_SNAPBACK}][/a][/div]

Yes I managed to do it but is it worth the trouble (to have my usb key plugged whenever I want to use swap)? I really would like a definite answer on the "swap on sd card is bad" issue.

kahm · « **Reply #12 on:** April 27, 2005, 06:20:24 pm »

Quote

Quote
Oneiros... should be possible. Mount the usb storage and format it as swap and then swap on.... look for instructions around here...
[div align=\"right\"][a href=\"index.php?act=findpost&pid=77198\"][{POST_SNAPBACK}][/a][/div]

Yes I managed to do it but is it worth the trouble (to have my usb key plugged whenever I want to use swap)? I really would like a definite answer on the "swap on sd card is bad" issue.
[div align=\"right\"][a href=\"index.php?act=findpost&pid=77252\"][{POST_SNAPBACK}][/a][/div]

Swap-on-flash-memory of any sort is "bad" - and that inludes the USB key. Flash memory has a limited number of writes. How many depends on the flash chip and it built in wear-leveling, which companies use to spread writes around to prevent burning out a particular section of memory early. How bad is going to depend on your swapfile activity.

A friend of mine burnt a CF card out using it on the desktop for swap in a week or so. Worst case scenario is a couple of days. What you're likely to run into using it on the Z is a year or two, ie - not that worrisome.

Oneiros · « **Reply #13 on:** April 29, 2005, 06:04:51 am »

Quote

Quote
Quote
Oneiros... should be possible. Mount the usb storage and format it as swap and then swap on.... look for instructions around here...
[div align=\"right\"][a href=\"index.php?act=findpost&pid=77198\"][{POST_SNAPBACK}][/a][/div]

Yes I managed to do it but is it worth the trouble (to have my usb key plugged whenever I want to use swap)? I really would like a definite answer on the "swap on sd card is bad" issue.
[div align=\"right\"][a href=\"index.php?act=findpost&pid=77252\"][{POST_SNAPBACK}][/a][/div]

Swap-on-flash-memory of any sort is "bad" - and that inludes the USB key. Flash memory has a limited number of writes. How many depends on the flash chip and it built in wear-leveling, which companies use to spread writes around to prevent burning out a particular section of memory early. How bad is going to depend on your swapfile activity.

A friend of mine burnt a CF card out using it on the desktop for swap in a week or so. Worst case scenario is a couple of days. What you're likely to run into using it on the Z is a year or two, ie - not that worrisome.
[div align=\"right\"][a href=\"index.php?act=findpost&pid=77257\"][{POST_SNAPBACK}][/a][/div]

Thanks Kham at last a clear explanation on this topics, I think I'll stay with the usb key, anyway I don't use it anymore.

Da_Blitz · « **Reply #14 on:** April 30, 2005, 03:05:10 am »

besides compiling large programs is there anyone who has any need for more than 64MB of RAM, i like to keep tabs on my memorey and i dont think i have ever come close to using it all

that said thogh i would kill for 128 or even 256 of both flash and ram in my c3000.

after reading the sdram data sheets of several manufactrers i noticed that if you are not using the ram (ie reading and writeing) but are just refresing then the power consumption is quite low. its only when activity begins that the power goes up. another intresting thing is that reads as far as i know are destructive and the data has to be rewritten back to the cell during a read meaing that reads take as much power or in some cases more power than a write

feel free to correct me if i am wrong, this infomation was gleened from reading the sdram data sheets from a few manufacteres and only applies to "low power" sdram chips for use in the mobile market, i didnt read up on the normal chips (see www.arstechnica.com for a detalied description of how dram works or even www.howstuffworks.com"

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Author Topic: Why 64mb? (Read 5301 times)