[TESTING] Updated 5/14/11 New Kernel - Temp Test - SOD Fix!

[ffkip911]

fish----ahhhh, gotcha. NDNO is the man, he got me up an running on it.

Now here's a question, spinning hard drives can become "etched" also, when data is stored, the spinning disk sometimes needs to be defraged-----however, i was under the impression that flash has no such drawbacks because there is nothing physically moving. so how could pushing and pulling data from one section wear it out??

[fishingmedic]

Originally Posted by ffkip911

fish----ahhhh, gotcha. NDNO is the man, he got me up an running on it.

Now here's a question, spinning hard drives can become "etched" also, when data is stored, the spinning disk sometimes needs to be defraged-----however, i was under the impression that flash has no such drawbacks because there is nothing physically moving. so how could pushing and pulling data from one section wear it out??

I just remember reading in one of the threads here about constantly reformatting the sd card because there is only so many read/write cycles that a sd card can handle and that constant reading/writing to the card can cause it to prematurely die, but I'm not an expert by any means on this. Maybe arrrghhh or one of the dev's could give more info on this. I believe it was Nate who was talking about it, but don't quote me on that.

[ModmyPPC]

Originally Posted by fishingmedic

I just remember reading in one of the threads here about constantly reformatting the sd card because there is only so many read/write cycles that a sd card can handle and that constant reading/writing to the card can cause it to prematurely die, but I'm not an expert by any means on this. Maybe arrrghhh or one of the dev's could give more info on this. I believe it was Nate who was talking about it, but don't quote me on that.

When I bought my sdcard from newegg it mentioned there being a limit (Durability: 10,000 insertion/removal cycles) to the read/write cycles... Thats why im hesitant on reformating my sdcard all the time.

Im curious though if its every time I copy a file its considered one write cycle. or is it if I copyied 10 files at once thats considered one write cycle.

It cost me like 60$ its a transcend 16gb class 6.

http://ec.transcendusa.com/product/I...ID=TS16GUSDHC6

[bitslizer]

Originally Posted by fishingmedic

I just remember reading in one of the threads here about constantly reformatting the sd card because there is only so many read/write cycles that a sd card can handle and that constant reading/writing to the card can cause it to prematurely die, but I'm not an expert by any means on this. Maybe arrrghhh or one of the dev's could give more info on this. I believe it was Nate who was talking about it, but don't quote me on that.

fish is right, all current flash memory, there's a limited # of read/write they can perform before they simply wear out. think of it as number of time you can turn on a lightbulb before it burn out, even though no moving part, they can still eventually wear out, depending on the flash memory, I think the design life is typically over 10k write cycle though.

[ndno]

Originally Posted by ffkip911

fish----ahhhh, gotcha. NDNO is the man, he got me up an running on it.

Now here's a question, spinning hard drives can become "etched" also, when data is stored, the spinning disk sometimes needs to be defraged-----however, i was under the impression that flash has no such drawbacks because there is nothing physically moving. so how could pushing and pulling data from one section wear it out??

The individual blocks on the SD card have a limited life cycle, like 1000000 writes or something like that. Once those writes are exhausted, they can longer be erased and written to. So if you created a swapfile and that swapfile occupies the same physical area on the card all the times, that area will wear out quickly if linux is constantly swapping inactive RAM data from/to that area. I know we use the SD card to save data / apps / etc, but writing is limited on that (unless you're constantly installing software every second of the day); also, the NAND, card driver under WinMo and Linux is smart because they're designed to do wearleveling; that is, spread out the writes evenly all over the area of the Nand/card so that no one area gets exhausted quickly. On a SD card or NAND, I believe each block contains a header section that tells the OS how many writes have been written to it, so this is how it knows what blocks have been written to more or less; I'm not sure but I believe that's how it works. I believe "reading" is unlimited but if you can no longer write to a worn out SD card, it's useless. So that's why using swapping is not recommended. The advanced features of swapper 2 is nice; you can tell it to delete the swapfile and create a new one each time android boots; when creating the new swapfile, it does at a different area of the Sd card so the previous area is not exhausted out. I believe hard drives have a much longer write life cycle. Any expert, please correct me if I'm wrong on this.

Edit: oops, everyone beats me to the explanation And mine is inaccurate about the write cycles, I guess it's in the thousands, not millions, which means you can easily wear out that card using swapping.

Sent from my FRX05-ized TP2

[ndno]

Originally Posted by ModmyPPC

When I bought my sdcard from newegg it mentioned there being a limit (Durability: 10,000 insertion/removal cycles) to the read/write cycles... Thats why im hesitant on reformating my sdcard all the time.

Im curious though if its every time I copy a file its considered one write cycle. or is it if I copyied 10 files at once thats considered one write cycle.

It cost me like 60$ its a transcend 16gb class 6.

http://ec.transcendusa.com/product/I...ID=TS16GUSDHC6

I'm not sure about Sd cards, but I know that on the Nand, the individual unit of storage is a block. Depending the the Nand hardware, a block can be 32kb, 64kb, 128kb, etc. The write cycle is per block. So if you copy a file, let's say 64kb and the block can hold 32kb, the nand driver will use 2 blocks (plus any overhead) to write that file; the driver is smart enough to use wearleveling to spread out the writes over the whole Nand; it may be similarly with a sd card.

Sent from my FRX05-ized TP2

[ffkip911]

thanks guys---a lot of good info.

personal experience. facebook widget (the big one) tends to cause locks/no wakeups on the new kernel

swappy2 - a marked improvement, I have since changed my settings due to the great info from ya'll (plus I was looking at the info page and wasn't caching as much as I thought I would)

dropped my settings to
swap size - 64MB (down from 12
swappiness - 20 (down from 60)
recreate swap file - checked
reformat swap - unchecked

speed is still amazing!

[ndno]

ffkip911, here's a forum on swapper 2 in which some folks used it on the Cyanogen android phones:

Swapper 2 - CyanogenMod Forum. Some good info from users.

If you have a very slow SD card, I don't think using swapper 2 is recommended as it will be very slow. But then again, there are known problems with fast SD cards (class 6 and greater).

[ffkip911]

well, if flash can only be written onto a specific number of times----what happens to internal memory on the phone---every time I get a call, it is logged (stored) onto internal memory. at the end of the day, i erase it, only to get more calls that are logged (stored) at the same location on the memory....to follow the theory to its conclusion, I( should only get X number of days that the phone can work correctly -- ie log sms, mms, email, phone calls. after that, the internal memory would have met it's max number of write's and no longer store/log calls, sms, emails etc....

EDIT: I honestly have no idea how a flash drive actually stores information....playing devils advocate helps me understand. I am not discounting all the great info that has come out about swapping, I think this helps all involved to make the decision on whether to install the program or not.

[ndno]

Originally Posted by ffkip911

well, if flash can only be written onto a specific number of times----what happens to internal memory on the phone---every time I get a call, it is logged (stored) onto internal memory. at the end of the day, i erase it, only to get more calls that are logged (stored) at the same location on the memory....to follow the theory to its conclusion, I( should only get X number of days that the phone can work correctly -- ie log sms, mms, email, phone calls. after that, the internal memory would have met it's max number of write's and no longer store/log calls, sms, emails etc....

Memory (RAM) doesn't work the same; it's volatile memory and never needs to retain the data, unlike SD card. Different hardware.

Random-access memory - Wikipedia, the free encyclopedia

SRAM and DRAM are volatile. Other forms of computer storage, such as disks and magnetic tapes, have been used as persistent storage. Many newer products instead rely on flash memory to maintain data when not in use, such as PDAs or small music players. Certain personal computers, such as many rugged computers and netbooks, have also replaced magnetic disks with flash drives. With flash memory, only the NOR type is capable of true random access, allowing direct code execution, and is therefore often used instead of ROM; the lower cost NAND type is commonly used for bulk storage in memory cards and solid-state drives. A memory chip is an integrated circuit (IC) made of millions of transistors and capacitors. In the most common form of computer memory, dynamic random access memory (DRAM), a transistor and a capacitor are paired to create a memory cell, which represents a single bit of data. The capacitor holds the bit of information — a 0 or a 1 . The transistor acts as a switch that lets the control circuitry on the memory chip read the capacitor or change its state.

LOL, I think you're a little obsessed with getting more "virtual" RAM out of your SD card . I wouldn't risk my SD card to be obliterated by using a swapfile; that's just a fact. This topic has probably been debated many times.