NexusHD2 Android Forum

When I went to bed I enabled flight mode.
When I got up this morning I disabled flight mode again but the "mobile" icon did not come back.
Data did not work. Calls might have worked but I did not check.

Everything is fine now after a reboot. Will re-check tomorrow.

MarkAtHome wrote:I was under the (mis)understanding that TRIM was for SSD drives, and it is OS-provided. How is TRIM applicable to our HD2s in the manner being discussed, or is this TRIM different from what I am referring to?

At a low level NANDs and SSDs behave similarly since both use nonvolatile memory cells.

In essence the more a NAND is used the "laggier" the device's response gets because the controller first seeks out empty cells before overwriting cells that had previously held data. Then before they can be written to again they must first be "emptied". The more the NAND gets used the more cells appear to the controller as full even if the data has long since been deleted.

TRIM periodically scans the NAND and empties cells containing deleted data, which in turn speeds up the system.

Read through the Nexus 7 forum. There folks with systems containing large amounts of free memory space complain that their systems have over time slowed down to a crawl as if their NANDS are full. LagFix, which uses TRIM, is one of the recommended solutions and many there rave about it.

Now with Jellybean-4.3 and CM-10-2 TRIM is integrated (with proper kernel support) to keep NAND write speed optimized.

I'll excerpt from Wikipedia:

"A Trim command allows an operating system to inform a solid-state drive (SSD) which blocks of data are no longer considered in use and can be wiped internally. Because low-level operation of SSDs differs significantly from hard drives, the typical way in which operating systems handle operations like deletes and formats resulted in unanticipated progressive performance degradation of write operations on SSDs. Trimming enables the SSD to handle garbage collection overhead, which would otherwise significantly slow down future write operations to the involved blocks, in advance.....

Although tools to "reset" some drives to a fresh state were already available before the introduction of trimming, they also delete all data on the drive, which makes them impractical to use for ongoing optimization....

Flash drive specific issues:
Because of the way that file systems typically handle delete operations, storage media (SSDs, but also traditional hard drives) generally do not know which sectors/pages are truly in use and which can be considered free space. Delete operations are typically limited to flagging data blocks as "not in use" in the file system. Contrary to, for example, an overwrite operation, a delete will therefore not involve a physical write to the sectors that contain the data. Since a common SSD has no access to the file system structures, including the list of unused blocks/sectors, the storage medium remains unaware that the blocks have become available. While this often enables undelete tools to recover files from traditional hard disks, despite the files being reported as "deleted" by the operating system, it also means that when the operating system later performs a write operation to one of the sectors, which it considers free space, it effectively becomes an overwrite operation from the point of view of the storage medium. For traditional hard disks this is no different than writing an empty sector, but because of how some SSDs function at the lowest level, an overwrite produces significant overhead compared to writing data into an empty page, potentially crippling write performance.

SSDs store data in flash memory cells that are grouped into pages, with the pages (typically 4 kB each) grouped together into blocks (typically 128 pages per block, totaling 512 kB). NAND flash memory cells can only be directly written to when they are empty. If they are considered to contain data, the contents first need to be erased before a write operation can be performed reliably. In SSDs, a write operation can be done on the page-level, but due to hardware limitations, erase commands always affect entire blocks. As a result, writing data to SSD media is very fast as long as empty pages can be used, but slows down considerably once previously written pages need to be overwritten. Since an erase of the cells in the page is needed before it can be written again, but only entire blocks can be erased, an overwrite will initiate a read-erase-modify-write cycle: the contents of the entire block have to be stored in cache before it is effectively erased on the flash medium, then the overwritten page is modified in the cache so the cached block is up to date, and only then is the entire block (with updated page) written to the flash medium. This phenomenon is known as write amplification.

Operation:
The Trim command is designed to enable the operating system to notify the SSD which pages no longer contain valid data due to erases either by the user or operating system itself. During a delete operation, the OS will both mark the sectors as free for new data and send a Trim command to the SSD to be marked as no longer valid. After that the SSD knows not to relocate data from the affected LBAs during garbage collection. This results in fewer writes to the flash, reducing write amplification and increasing drive life.

Different SSDs will act on the Trim command somewhat differently so the final performance can also be different between different SSDs.

Trim irreversibly deletes the data it affects."

I hope this helps

When I connect my HD2 to my build in carkit via bluetooth, a connection is made. But whenever I try to do something (e.g. make a call), there is no response, and eventually the phone will reboot. Also I see my car constantly losing connection and trying to reconnect.
Anyway: bluetooth is not working (for me) in this version. It was working properly in version 2.x

Any suggestions? If needed, I am happy to provide more information

MarkAtHome wrote:I was under the (mis)understanding that TRIM was for SSD drives, and it is OS-provided. How is TRIM applicable to our HD2s in the manner being discussed, or is this TRIM different from what I am referring to?

Odysseus wrote:At a low level NANDs and SSDs behave similarly since both use nonvolatile memory cells.

In essence the more a NAND is used the "laggier" the device's response gets because the controller first seeks out empty cells before overwriting cells that had previously held data. Then before they can be written to again they must first be "emptied". The more the NAND gets used the more cells appear to the controller as full even if the data has long since been deleted.

TRIM periodically scans the NAND and empties cells containing deleted data, which in turn speeds up the system.

Read through the Nexus 7 forum. There folks with systems containing large amounts of free memory space complain that their systems have over time slowed down to a crawl as if their NANDS are full. LagFix, which uses TRIM, is one of the recommended solutions and many there rave about it.

Now with Jellybean-4.3 and CM-10-2 TRIM is integrated (with proper kernel support) to keep NAND write speed optimized.

I hope this helps

Yes, very much. Thanks, Odysseus. I am very familiar with TRIM, having a few Samsung 830 256G SSDs at my disposal, but I did not know that Android had built-in support of any kind. In fact, TRIM never entered my consciousness in regards to Android!

@tytung: does your kernel support it?

MarkAtHome wrote:Yes, very much. Thanks, Odysseus. I am very familiar with TRIM, having a few Samsung 830 256G SSDs at my disposal, but I did not know that Android had built-in support of any kind. In fact, TRIM never entered my consciousness in regards to Android!

@tytung: does your kernel support it?

I don't know.

I have issued with VPN, i tried on v.3.0 running well, after update v3.1 cannot connecting to VPN, maybe have same issue....???

Sent from my NT Droids HD2 using Tapatalk 2

Welcome
I have a little problem with WiFi relies on this with the phone starts searching for a network to WiFi but then something it is like to be suspended WiFi and does not want me to look for new networks.
Do you know of a way to this problem
thanks you in advance for your help
sorry for my english

MarkAtHome wrote:Yes, very much. Thanks, Odysseus. I am very familiar with TRIM, having a few Samsung 830 256G SSDs at my disposal, but I did not know that Android had built-in support of any kind. In fact, TRIM never entered my consciousness in regards to Android!

@tytung: does your kernel support it?

tytung wrote:I don't know.

That's honest! Hey, you have a whole semester to ponder this one, eh?

Is anyone having GPS issues?
I am using TMOUS HD2 with Native SD and my device cannot grasp its location.
Under WP7, GPS works perfectly fine.

Good day!
I-language user, so the quality of English do not abuse)

use your firmware for a long time, better than them no one has devised, thank you for your work!
There is only one negative - the maximum volume of the earpiece in an outgoing call, and this applies to all firmware gathered at your core. Can anything be done about it?


with respect, Stanislav