Possibility To Maybe Incrrease Ram With Flash Drive?


RetiredAccount

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Hey i got to thinking, and with Windows ReadyBoost (for Vista, sadly), you can increase the RAM in your computer with a flash drive. Is there any way we could create something similar for the Pandora? I don't know alot about ReadyBoost or how it works so I am asking you guys.
 
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The Pandora was originally only stated to have 128mb ram. the 256mb we're getting currently is more than enough. We're running Linux here, not windows. So keeping the ram usage down is quite simple. As for games needing more ram.... The PSP has what? 32mb and it hardly seems to suffer for it.

I guess if you really wanted you could format the flash drive as a swap partition.
 
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ReadyBoost does not increase your RAM. It's Flash memory that acts as a harddrive to increase HDD-speed. In the Pandora all the diskspace is Flash.
 
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Although it has nothing to do with ReadyBoost, you can certainly use a USB flash drive (or SD card space) for swap space, equivalent to more RAM, if you have a particularly memory-intensive program. Just remember that this will be very slow as compared to the internal RAM.
 
For comparisons:

A "Fast" SD will read between 15 a 30MB/s, and not taking in account slower write times.
The internal Ram does something along the lines off 75 a 100 times that.

Like Klaus said,

The basic idea is to put a lot off small files ( the type that a HD is normally bad with, but a flash drive not ( low access time ), and use the flash drive to load those system files ). Basic idea, but in practice, most readyboost sticks, suck ass when it comes to speed. In other words, the gain is minimal at best. On your PC your better off with Linux + Lots off Ram ( 4GB, 8GB :) ), and using the OS its caching, resulting in more speed, then anything else ( and saves your HD from those horrible I/O requests ).

The Pandora with 256MB ram can run for example: OS ( Linux ), FireFox, Gimp, MP3 player, and still has 75MB free ( maybe more, i don't remember if it was "real" free memory, or without the cache that Linux does ).
 
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Hopefully 256 is enough. I often get "low on memory" when I use my nokia n810 and that has 128mb of ram. Usually it pops up when I have 2-4 browser windows open and on image/flash heavy sites.
 
'Benjiro' said:
The Pandora with 256MB ram can run for example: OS ( Linux ), FireFox, Gimp, MP3 player, and still has 75MB free ( maybe more, i don't remember if it was "real" free memory, or without the cache that Linux does ).
I was always told it is pretty hard to get "real" free memory in Linux, exactly because the OS tends to gobble up all the RAM and use it as swap (which is the sensible thing to do. No use in letting all that RAM rot away).
 
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'Karel Jansens' said:
I was always told it is pretty hard to get "real" free memory in Linux, exactly because the OS tends to gobble up all the RAM and use it as swap (which is the sensible thing to do. No use in letting all that RAM rot away).
Not at all... I think you are using the wrong term. Swap = file on HD. You mean cache.

For example:

CODE

total used free shared buffers cached
Mem: 8199480 8151704 47776 0 25908 4835456
-/+ buffers/cache: 3290340 4909140
Swap: 5855416 29280 5826136



Total memory is 8GB

But, 3.29GB is really used. 4.9GB is used by the cache + 25MB in the buffer.
In other words, 4.9GB ( cache ) + 47MB ( Free memory ) + ( 26MB buffer ) is usable ( aka free ).

The swap ( lower line ), is using 29MB from the 5.8GB.
 
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'mali' said:
Maybe a RAMdisk could be a neat thing to do since we have so much RAM now.
You certainly could if you think you'd get a decent speed increase for something drive intensive by having a 128 meg ramdrive. That said I personally think the ideas a tad insane because I don't think there's going to be any issues with loading time off the SD cards. I think the availability of the ram itself might help speed things a tad more... at least in cacheing things you run often. Alot of the optimization benefit of ramdrives is taken care of by the linux kernel itself if the rams free. Though if you want to do it cause its a cool thing to do then go right ahead.

--edit-- on a related side note, I read an article once about someone writing down the effects of moving his swapfile to a ramdrive in attempt to optimize it, I was amused --/edit--

--double edit-- perhaps I should start calling them RAMdisks to be more correct to current terminology, seeing as that's the proper name for them... though I probably won't ... --/edit--
 
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'fireball87' said:
You certainly could if you think you'd get a decent speed increase for something drive intensive by having a 128 meg ramdrive. That said I personally think the ideas a tad insane because I don't think there's going to be any issues with loading time off the SD cards. I think the availability of the ram itself might help speed things a tad more... at least in cacheing things you run often. Alot of the optimization benefit of ramdrives is taken care of by the linux kernel itself if the rams free. Though if you want to do it cause its a cool thing to do then go right ahead.
I'm a real linux n00b, but judging from some post on this board I figured, that linux handles memory completely different(more efficient) than XP, Vista. The latest JKK video about his modified Aigo(512MB RAM, XP embedded) made me think about it. He used a technique that completely bypasses the SSD and writes everything to RAM. I was very impressed by the internet browsing speed without any lag.
I might try it one day and put Firefox on a RAMdisk and see what happens.
 
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'mali' said:
I'm a real linux n00b, but judging from some post on this board I figured, that linux handles memory completely different(more efficient) than XP, Vista. The latest JKK video about his modified Aigo(512MB RAM, XP embedded) made me think about it. He used a technique that completely bypasses the SSD and writes everything to RAM. I was very impressed by the internet browsing speed without any lag.
I might try it one day and put Firefox on a RAMdisk and see what happens.
It handles it more efficiently more then different yes. Ram drives only can optimized things that are actually reads/writes from the hard-disk. When you load something in linux for the first time (a load time that is going to happen some time even with a ram disk... where it would happen at boot cause things aren't just going to appear in ram, which loses its content every time the machine loses power or is turned completely off) it will cache what you've loaded for as long as there is still memory left to store it. A ramdisk is basically telling the kernel you know what to optimize more then it does, so for very specific things it will give a speed boost but only on disk read/write operations (a database which writes every change to the hard drive would get a huge speedboost for example). Firefox would never get much of a boost off of a ramdisk since it doesn't read or write much from the hard drive. It would load much much faster, but other then that it should run nearly the same speed (unnoticeable faster since it doesn't read or write all that much information). I theorize that the speed of firefox you noticed was more do to other optimizations and factors then the speed of the ram drive. And since when is firefox not snappy on a halfway decent system with 512 megs of ram?

Anyway, running a ramdisk is telling the system that you know better how to deal with optimization then either the program software developer (who writes things to the hd that could be written to ram) or the operating system developer (who decides what should be cached based on what you've loaded recently). And is fairly overused to the point that it probably slows down quite a few systems overall. I wouldn't recommend it unless you either very much know what needs to be optimized and why (like huge file IO apps), or really want to force something to be in memory at all times, the latter though often will do more harm then good.

--edit-- do note I'm not an expert on the subject, I've not messed with them much, but I am aware of how and why they work and for what reason they're used--/edit--
 
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If you are desperate enought you can put a swap partition on an SD card: it will be slow, it will probably thrash your card but will also work out of the box with just a couple of command line commands.

It would be probably useful for big on device compilations, not for games or the like where speed is essential.
 
Thanks for the explanation :)
I've checked the vid again and what is used is called enhanced write filter
QUOTE
Enhanced Write Filter (EWF) provides the ability to write-protect a run-time image. By redirecting all write requests to either a separate disk partition or RAM, EWF allows the run-time image to maintain the appearance of a writeable run-time image. Additionally, Enhanced Write Filter provides the ability to deploy a run-time image onto read-only media, such as a CD-ROM.

CODE
http://msdn.microsoft.com/en-us/library/ms912906.aspx


Does something like this exist for Linux/ would it make a difference if it existed?

Edit:
QUOTE
Additionally, Enhanced Write Filter provides the ability to deploy a run-time image onto read-only media, such as a CD-ROM.

This paragraph lets me think about those Linux on CD thingies, is this similar?
 
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Yes, the Linux LiveCDs use a similar technology. There's a few variants, but I think one of the most common ones is called "UnionFS". It joins a read-only device [a compressed filesystem image on the CD-ROM] with a read-write device [A RAM-based filesystem or RAM disk]

edit: This is how I installed things and ran an SSH daemon on my Pentium II that wouldn't even recognize a hard drive, I ran a Puppy Linux LiveCD in RAM. It was a cool trick, but it couldn't save the computer from sucking.

It's pretty cool, but it doesn't really improve performance since you still have to load things from the CD.

I don't think it really applies to the Pandora.

"Maybe a RAMdisk could be a neat thing to do since we have so much RAM now."

Maybe if you're talking about desktop machines. I'm running Ubuntu just fine in 2GB of RAM. If I had 8 or 16 GB like a full, new desktop system, I wouldn't know what to do with it. I probably would have a RAM disk..

I think the Pandora will be fine with 256 MB of RAM, no ram-disks, no funny LiveCD business, and no swap.

For the love of all that is good, no swap.
 
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QUOTE
It's pretty cool, but it doesn't really improve performance since you still have to load things from the CD.

I don't think it really applies to the Pandora.

In Pandora's case the CD would be the NAND. What interests me is, if there would be a difference in speed between letting the OS handle the RAM on its own or applying a write filter in a clearly defined usage scenaryo like surfing with firefox. I don't talk about games or other stuff, just browsing the net.
If it would be more efficient, someone could make a multiboot with a MID option that starts a write filter configuration just for surfing.
 
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'mali' said:
This paragraph lets me think about those Linux on CD thingies, is this similar?
--edit-- the unionfs explanation is way better/more current/accurate then mine so I'm going to edit this to hold more useful information. I'll leave the post up real small incase someone wants to read and judge me and so forth.

Anyway...

Yes its very simular.

Anyway if all you're going to be doing is running firefox and your net apps the systems automatic caching should suit you fine. The first time you run them the loads will be cached and as long as you don't run alot of things and push them out of cache it shouldn't ever be an issue... and if all you want to run is truely a few web apps there will probably be plenty of cache for all of them. If there isn't then you're probably slowing something down for a minor speed boost I doubt you'll even notice.


Its looks more or less a combination of light sandboxing and a ramdisk.

CODE
http://en.wikipedia.org/wiki/Sandbox_(computer_security)

Depending on how you set it up the Linux equivalent to this is infact a ramdrive thanks to the fact that most of the locations a linux system generally writes to only a few places on the hard drive (that are directly tied to the user). Many distros that run off of a CD/DVD use a ramdisk to hold these files.

That said its generally it isn't used for optimization so much as running an os from a read only system, thus giving you the benefits of either booting from a DVD or wiping the system clean every time it is rebooted to reduce maintenance (I know quite a few school's that use such a system throughout the campus to make their lives a few thousand times easier).

(The security advantage of a full whipe every boot isn't so neccicary on linux for the two reasons of there are far less linux threats and a properly managed user shouldn't be able to change anything outside of his own accounts files, therefore linux users are in many ways sandboxed from the system in this way by design.)



--edit-- Also alot of people like to put their web caches on a ramdisk to increase their speed, but you could get the same speedboost by just changing firefox's memory cache settings in about:config... which is probably the better way of doing it. ... And damn, every time i edit which is often my apostrophes are doubled, so lame...--/edit--
 
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