[EVO 4G Android Development] ricsim78:
Hey there, to answer your question about the SD:Ext

If you are coming from another ROM that uses Apps2SD (Fresh does, my old ROMS did, Virus's does, etc.) It tends to leave stuff leftover. This can include programs and data.

If you make a swap file, basically you are using the SD:Ext function.

While my ROM does not use the SD:Ext, most other ROMS do and this can lead to stuff not being properly wiped. One feature of Apps2SD is that programs stay installed on your SD card.

This can lead to conflicts, like duplicate apps and other problems. ROM makers can also set the ROM to store other information on the SD:Ext.

So lets say you do a usual wipe, (Data, Cache, Dalvik). Well yes that wipes the phone memory, but then the swap from the previous ROM will still be left over, as can other information (data, apps, etc.). So now you have a clean phone yet have a dirty SD card.

SD:Ext wiping just clears that information out. If you run it after using a ROM that uses Apps2SD, it will clear out the programs that were stored on SD. Then you have a clean phone and clean SD card. You can even clean SD:Ext and then go to the partition menu and select repair SD:Ext, this will check for errors on your SD Card's SD:Ext portion.

It does NOT wipe your whole SD:Card; formatting or partitioning it does.

If you do decide to format or partition your SD Card, backup the whole card on your computer. Then format it and copy everything back.

I suggest you format it using the default settings and then select ext2 to ext3. This makes it compatible with anything that tries writing to those portions (for example, it is required to activate Apps2SD).

The Apps2SD my newest ROM comes with is vastly different from the Apps2SD I am talking about. The Apps2SD I included just makes it easier to put whatever information that your apps can put on your SD card there, it is the same as going to Settings>Applications and moving everything to SD.

Darktremor's Apps2SD is a totally different animal. It is a script that is run by the init.d and it basically forces Apps to go to the SD card. It also stores the Dalvik Cache on the SD card instead of the /Data portion (where it is stock and in most cases) or the /cache portion (where my ROM is programmed to put the Dalvik).

The downside of using Apps2sd is that not only does it kill your Micro SD card faster, it can actually slow things down a bit because the SD card is way slower than the internal memory. Also it is recommended to have at least a class 6 (speed) memory card, which not everyone has. Removing it did speed things up in this ROM's case and I felt it was better left as an option rather than forcing it on people in my ROM. Heck, I don't even have a Class 6 memory card!

My ROM is setup to use three scripts, Compache, Zipalign, and Dalvik to cache.

-Compache: Compresses the cache portion to free up more main memory. It is a classic space-time tradeoff, so it CAN speed things up. But the phone also has to compress and decompress the information each time, so it takes CPU to do it. It did seem to make my ROM a bit quicker in any case and freed up a bit more memory.

-Zipalign: Makes all the apps on your phone open faster. My ROM does this work each time when you boot up, so it is a good idea to install all your apps and reboot and let it do it's magic.

-Dalvik2Cache: Does exactly what it sounds like, instead of eating up App memory, the Dalvik is placed in the /cache portion rather than the default /data portion. The /data portion is also where your apps are stored.

These scripts are very responsible for how fast my ROM is and why there is so much free memory available. There is a debate on Compcache whether it hurts or hinders speed with Froyo 2.2. Considering how fast my ROM is, I definitely do not think it is hurting anything!

Hope this helps!