zain
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Just a thought: Increase in Memory

Thu Jul 19, 2012 9:10 am

the PI comes standard with 256 Megs RAM. Now, my idea, Windows 7 has readyboost, the ability to use a USB key as extended RAM, can that be implemented in one of the Linux distros for PI ;)

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mahjongg
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Re: Just a thought: Increase in Memory

Thu Jul 19, 2012 9:17 am

"readyboost" isn't "the ability to use a USB key as extended RAM". In fact its just a memory stick that speeds up booting a little bit. it does NOT increase RAM.

Its possible to partly boot from a memory stick instead of from the SD-card, but thats a whole other issue.

obarthelemy
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Re: Just a thought: Increase in Memory

Thu Jul 19, 2012 4:25 pm

@OP: I'm amazed at how people misunderstand readyboost. Flash memory is good a small random reads, HD are good at large sequential reads/writes. So ready boost takes the small files involved in booting/launching apps from the HD, copies them to flash, and you get the best of both worlds. That's it: disk cache. No RAM involved.

Why MS hasn't come up with a readyboost that can use SSDs instead of USB sticks is a mystery.

zain
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Joined: Thu Jul 19, 2012 9:06 am

Re: Just a thought: Increase in Memory

Thu Jul 19, 2012 9:05 pm

Ok guys thanks for that clarification.
Always assumed that it added to the random access memory. This what I read at a blog:

http://gravitech.blogspot.com/2011/06/r ... linux.html

So I assume if we get this working on a raspberry pi distro, it would definitely speed up processing etc.

Is this possible?

zain
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Re: Just a thought: Increase in Memory

Thu Jul 19, 2012 9:25 pm

I ordered a 32GB SD card for when my raspberry pi when it arrives. I intend to do the following testing:

1. Partition the SD card into two, 1 for the OS and 1 for the Linux swap partition
2. First will do a test on memory hungry applications without large swap partition; will record times and successes of applications
3. Second will do a test on same applications as #2 and record times and successes, load times, speed of specific tasks
4. Compare results from #2 and #3 and report back to this thread
5. If this helps in aiding the 256megs of RAM, well good for me and others who will benefit from this; else
{ bribe some admin to delete this thread}
:twisted:

This is just an idea I have and please help by guiding me and not thrashing me

;)

bredman
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Re: Just a thought: Increase in Memory

Thu Jul 19, 2012 9:51 pm

It is not a good idea to use an SD card as swap.

SD cards can only survive a limited number of writes. After this number of writes, the card will lose capacity permanently. You cannot repair this damage by reformatting the SD card.

Using swap will chew through your SD card very quickly and is not recommended.

zain
Posts: 4
Joined: Thu Jul 19, 2012 9:06 am

Re: Just a thought: Increase in Memory

Fri Jul 20, 2012 2:05 pm

If it works then will address the problem of SD card failure. Inexpensive.

redfox05
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Re: Just a thought: Increase in Memory

Tue Jul 24, 2012 2:25 pm

Zain,

just to give you some positive support, I think this is a great idea to try. After all, where is the harm in trying. Yes I do realise what was said about a finite number of writes to the SD card, and using it as swap will burn it through quicker, and also using SD as RAM is not particularly efficient being Random Access etc, but as long as this is understood and taken into consideration, then there is no harm in seeing if it would actually improve performance. As long as the user understands the risk. Its like overclocking your CPU, there is a risk, now the question is, is it worth it, and even if its decided too risky/not good enough and not implemented, it will be interesting to at least know, knowledge wise.

Redfox05

pygmy_giant
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Re: Just a thought: Increase in Memory

Tue Jul 24, 2012 2:41 pm

If the foundation ever meke a model C, would it be possible to incorporate a memory expansion bus or is the whole point of a 'system on a chip' that it is a sealed unit...?

Personally I think the restricted memory is a good thing as it encourages efficiency. I also think that 256 Mb is alot - remember the BBC micro?
Ostendo ignarus addo scientia.

jamesh
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Re: Just a thought: Increase in Memory

Tue Jul 24, 2012 4:16 pm

Its quite feasible to use SD card as swap - I do it on the Raspi. It's not fast, but it does work, and as others have pointed out - SD cards are cheap, and won't die that quickly.

James
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