Terms and Definitions of Android

A2SD+

A2SD+ is an extension of Android 2.2 Froyo’s native support for installing apps on the SD card, but it virtually installs every app to the external storage. You can more or less expand your internal storage with the size of the partition you create on your memory card — because you need to partition your SD card to use A2SD+. It’s great if your Android phone has a limited amount of internal storage space. Most Android ROMs have built-in support for A2SD+.


•ADB

Android Debug Bridge is a tool that comes with the Android SDK that allows you to control and interface with your Android device. It is located in the tools folder when you unpack the SDK. Visit http://wiki.cyanogenmod.com/index.php?title=ADB for a list of commands


•Alpha

Usually pertains to a "test" or "initial" release. Alpha software can be unstable and is mainly used for preview and testing purposes.


•AMOLED

Active Matrix Organic Light Emitting Diode


•AOSP

AOSP is short for Android Open Source Project, and when the term is used in ROM descriptions, it usually indicates that the ROM in question is based on the Android source code provided by Google itself, and not on some other ROM project or a company’s firmware.


•APK

The file type for Apps used by Android, you can rename it to .zip and open them.


•ARM

A type of processor architecture http://en.wikipedia.org/wiki/ARM_architecture


•BFS

Brain Fuck Scheduler
It has been reported to improve responsiveness on light-NUMA (non-uniform memory access) Linux mobile devices and desktop computers with fewer than 16 cores.


•Bloatware

Software or 'apps' that you don't need, but come preinstalled to a device's /system partition, meaning that you cannot remove them unless the device has been rooted.


•Bootloader

The bootloader executes code before any operating system is launched. On Android devices, the bootloader is usually locked because manufacturers want you to use the version of Android they’ve provided. With a locked bootloader on Android phones, custom ROMs cannot be flashed.


•Brick

When your device is rendered unusable from improper flashing or physically damage such that it becomes like a useless piece of brick.


•BusyBox

BusyBox is an app on your phone that will give you access to additional Linux/Unix based commands. You may need BusyBox installed to perform some root level tasks, and some other apps that require root access may need BusyBox installed as well. BusyBox is self-dubbed “The Swiss Army Knife of Embedded Linux.”


•CFS

Completely Fair Scheduler
It handles CPU resource allocation for executing processes, and aims to maximize overall CPU utilization while maximizing interactive performance.


•Compcache

virtual swap, setting aside a certain percentage (usually 25%) of your RAM as 'compressed' swap. Compcache compresses the data that would normally go to swap, then moves it back into RAM, and reverses the process when moving it out of the 'compressed' swap.


•CyanogenMod or CM

CyanogenMod, often abbreviated CM, is a custom version of vanilla (more or less unmodified) Android. It’s the most popular custom ROM for Android – a community effort, and many other ROMs are based on CyanogenMod. Among other things, it adds a bunch of extra customization features and options.


•Dalvik & Dalvik cache

Dalvik is the cryptic name of the virtual machine (VM) in Android, and it’s the basis for running apps (with the .apk filename extension) on the platform. Before Android apps are launched, they’re converted into the compact Dalvik Executable (.dex) format, which is designed to be suitable for systems that are constrained in terms of memory and processor speed.

The Dalvik cache is a simply the cache used by Dalvik, and it’s the result of Dalvik doing optimizations of running apps. Some Android ROMs allow you to move the Dalvik cache to your SD card, in order to free up internal storage.


•Data2SD / D2EXT / D2SD

If a ROM supports data2SD, D2EXT, or simply D2SD, it means that the /data folder on your Android phone’s internal storage can be moved to your memory card instead. That’s a good thing, because it will free up precious internal megabytes and leave more room for apps and games. Some say that having the data stored on your SD card is slightly slower, though.

D2ext is a short way of saying “data to the extended file system”. It requires that you have created a partition on your SD card.


•Deodexed

When a ROM has been deodexed, it means that its apps have been prepared so they can be modified. Deodexed ROMs feature apps that have been repackaged in a certain way. Android applications, .APKs, contain .odex files that devs supposedly use to save space. These .odex files are extracted from the application packages and put in the /system/ folder on your phone, to speed up boot processes and to allow parts of applications to be preloaded.

However, this makes hacking and modifying those apps difficult because parts of the apps have been extracted to another location. Deodexing means that all pieces of an application package are put back together into one file, and it makes sure that a modified .APK won’t conflict with some separate odexed parts located somewhere else. Developers of custom ROMs choose to deodex their ROM packages, since it lets them modify various .APKs, and it also makes theming possible after the ROMs have been installed.


•DVM

Dalvik Virtual Machinehttp://en.wikipedia.org/wiki/Dalvik_(software)


•EXT2/3/4

This refers to ext2, ext3, and ext4 partitions on your SD card. They’re extended file systems for Linux that can be used by Android, usually in order to preserve internal storage space. Many custom Android ROMs require that you have an ext2, ext3 or ext4 partition on your memory card. Ext2 is the oldest type of extended file system, and ext4 is the newest. Some say that ext4 will put an unnecessary strain on your memory card, because it writes to it so much, and I think the ext3 file system currently is most common.

So what exactly is a partition? It’s a part of a hard disk, or a SD card in this case, that’s separated from the other parts. Think of partitioning as dividing your SD card into two sections that have different purposes.


•Fastboot

Fastboot is essentially a boot menu that you can do stuff from before Android is launched. “Fastboot is a protocol used to directly update the flash file system in Android devices from a host over USB.”


•Firmware

A phone’s firmware is basically its operating system. A “firmware update” means that the operating system, the software that controls the phone, is updated. “Stock firmware” means that the firmware is unmodified: it’s the version of the operating system the phone’s manufacturer delivers.


•Flash and flashing

To flash a custom ROM, or a firmware, simply means that you install it. So, flashing is the process of installing a new version of the Android operating system, or just parts of it, like the radio. Flashing new ROMs is done via the Recovery Mode, usually with ClockworkMod Recovery.


•Force-close (FC)

An alert to notify the user that a certain app / process has crashed.


•GPU

A graphics processing unit is a specialized microprocessor that offloads and accelerates graphics rendering from the central (micro-)processor.


•Governor

refers to a set of code that controls the CPU's behavior


•HBoot

HBoot is loaded immediately when your phone is switched on, and it’s mainly responsible for checking and initializing the hardware and starting the phone’s software. It can also be used for flashing official software releases, as well as a few other things. HBoot can be compared to the BIOS on a computer.


•I/O Scheduling

Input / Output Scheduling is a term used to describe the method computer operating systems decide the order that block I/O operations will be submitted to storage volumes. I/O Scheduling is sometimes called 'disk scheduling'.


•JIT

Just-in-time compiler http://en.wikipedia.org/wiki/Just-in-time_compilation


•Kang

Is a re-compiled / modified version of a code originally created by someone.


•Kernel

The kernel is the central component of most operating systems: it’s a bridge between applications and the actual data processing done at the hardware level. The Linux kernel was initially created by legendary Finnish computer science student Linus Torvalds in 1991. Android kernels are often customized, optimized and modified for different purposes, such as over-clocking the processor or extending the battery life. Custom ROMs usually include a new kernel.


•LCD Density

Similar to screen resolution adjusted by changing the DPI (Dots per inch) setting of a device. A smaller DPI value will result to smaller characters and a bigger DPI will make characters appear bigger.
This setting is the exact opposite when you're changing screen resolutions with your desktop PC. (Small reso = Big icons , Big reso = small icons)


•logcat

An Android built-in debugging log


•mount

It is to link(mount) a partition/filesystem to any location.


•NANDroid & NANDroid backups

NANDroid will let anyone with root access make a complete system backup. It lets you create a backup of every piece of information on your phone, and it can be restored later whenever you want. NANDroid backups are usually performed before flashing a new ROM, in case anything goes wrong, or if you want to return to your previous setup later. NANDroid backups are created from the Recovery Mode, often with ClockworkMod Recovery.


•OC (Over-clocking)

The method of increasing the CPU clock speed.


•port (porting)

The process of making a certain application/mod/software compatible with another device/version


•Radio

It’s the radio on your phone that handles communication, the radio that sends and receives voice and data. Flashing (installing) a new radio can improve your reception, and bring other benefits. A radio is flashed via Recovery Mode, just as a full Android ROM.


•Radio interface layer (RIL)

Android provides a Radio Interface Layer (RIL) between Android’s telephony services and the radio hardware. Developers and enthusiasts enjoy messing around with every part of Android, and some of them modify the RIL, just like Android itself, the kernel and the radio, to make it better.


•RC

When it comes to Android ROMs, RC means Release Candidate. It’s a candidate for the final release of a ROM, and they can be considered ROM betas.


•RAM

Random Access Memory (RAM) is temporary data storage that the CPU uses during calculations. The more RAM a device has, the more calculated results the CPU can store - which means less time the CPU has to do the same thing over and over again. In other words, the CPU can check RAM to see if it has already made a particular calculation in the recent past. If it has, it can use the pre-computed results instead of wasting processing time recomputing the same calculation. In short, more RAM means a more efficient (and faster) device.


•Recovery

You can think of the Recovery Mode as Android’s equivalent of the BIOS on your computer. Not quite, since Hboot may be more similar to your PC’s BIOS. It’s a boot menu that is shown without Android being loaded, and it gives you access to certain features such as doing complete backups of your phone (Nandroid backups) and installing custom ROMs. ClockworkMod is the most popular Recovery Mode, and it’s installed with the app ROM Manager.


•Root / Root access

When someone mentions root, it usually just refers to having root access on an Android phone – also called being a root user, or a superuser. An app / user with root access is able to modify and read the contents of the Android OS.


•S-OFF (security off)

On the HTC Desire and several other HTC Android phones, the company has implemented a form of “security.” It’s called @secuflag, and it controls whether your phone has its NAND or flash unlocked. S-ON (security on) will read-lock your /system and /recovery partitions, blocking you from performing certain root level actions directly from Android.

You can disable this security measure with S-OFF (security off), although you risk bricking your phone in the process (worst case scenario).


•SDK

Software Development Kit. You can find the Android SDK at http://developer.android.com/sdk


•Sideloading

It means installing applications without using the official Android Market and is usually done via the phone's file manager.


•Stock

Usually means "default" or "factory setting"


•SuperUser

Android is a Linux-based operating system, and in Linux, there is something called root access. When you root your Android phone, you will get superuser access. The superuser, or root user, is sort of a special user account for system administration. SuperUser is also the name of an app, which lets you grant or deny superuser privileges to other apps.


•Swap

virtual RAM. With swap, a small portion of the hard drive is set aside and used like RAM.


•Terminal and Terminal Emulator

Terminal Emulator, sometimes just referred to as Terminal, is an app that lets users access Android’s built-in Linux command line shell. The application emulates a Digital Equipment Corporation VT-100 terminal, and it’s mostly useful for programmers and for those with root access.


•Tethering

Using a wireless device (e.g. an Android phone) to share it's wireless data connection to another device (e.g. laptop). With an Android device, the wireless data connection can usually be shared via WiFi, Bluetooth or USB connection.


•Threshold

refers to a limit or value that is used to trigger a certain event within a script / app.


•Tweak

an optional application or script that alters the behavior of the hardware and/or software


•UV / Undervolt / Undervolting

reducing the stock CPU voltage to run at less voltage


•Vanilla/Stock

A clean, unmodified version of something. In the context of Android ROMs, vanilla refers to the stock ROM that came pre-installed on the device.


•Widget

An application that lives (in other words, is always running) on the homescreen instead of being 'run' like a regular app. Common examples are calenders and weather widgets.


•Wipe

Usually refers to wiping data and cache partitions of the device.


•Zipaligned

Zipalign is a tool that optimizes the way an Android app (.APK) is packaged. It enables Android to interact with the application more efficiently, and in doing so, it has the potential to make the app and the entire Android system much faster. Zipaligned applications are launched more quickly, and they use less amounts of RAM. So, thumbs up for zipaligned Android ROMs.