一、分区（Partition）概念
Partitioning a hard drive divides the available space into sections that can be accessed independently. An entire drive may be allocated to a single partition, or multiple ones for cases such as dual-booting, maintaining a swap partition, or to logically separate data such as audio and video files.
同时，需要注意下面的内容
1.分区 vs 磁盘 vs 文件系统
分区
磁盘
文件系统
2.Master Boot Record (MBR) vs GUID Partition Table (GPT)
MBR：MBR分区表(即主引导记录)大家都很熟悉。所支持的最大卷：2T，而且对分区有限制：最多4个主分区或3个主分区加一个扩展分区
GPT： GPT（即GUID分区表）。是源自EFI标准的一种较新的磁盘分区表结构的标准，是未来磁盘分区的主要形式。与MBR分区方式相比，具有如下优点。突破 MBR 4个主分区限制，每个磁盘最多支持128个分区。支持大于2T的分区，最大卷可达18EB。
二、为什么分区很重要
对于嵌入式开发而言，它不是通用的，带有定制的意味在里面，也就是说不同的芯片设计时是有较大差异的，我们是必要搞清楚这些差异的点。在这些差异点当中，分区是一个很好的切入方式。
另外，嵌入式设备有很强的升级需求，OTA升级的时候，需要对分区有详细的了解，这样才能搞清楚升级具体的影响。
因此，我们需要搞清楚系统有哪些分区，每个分区是什么作用？
三、工作方法
搞清楚分区的方法包括：芯片商资料、自我研究
四、常用命令
1.cat /proc/partitions
2.cat /proc/mtd
3.parted
4.fdisk
参考资料
http://tldp.org/HOWTO/Partition/
https://wiki.archlinux.org/index.php/Partitioning
附：高通各分区的含义
Label Purpose of this partition
Modem Partition for modem
Fsc Cookie partition to store Modem File System’s cookies.
Ssd Partition for ssd diag module. stores the encrypted RSA keys
sbl1 Partition for secondary boot loader
sbl1bak Back up Partition for secondary boot loader
Rpm Partition for rpm image
Rpmbak Back up Partition for rpm image
Tz Partition for tz image
tzbak Back up Partition for tz image
Hyp Partition for hypervisor image
hypbak Back up Partition for hypervisor image
Dsp Partition for adsp dymanic loaders image
modemst1 Copy of Modem File System (Encrypted)
modemst2 Copy of Modem File System (Encrypted)
DDR Partition for DDR.
Fsg Golden copy or backup of Modem File System (Encrypted). Also used to pre-populate the file system.
Sec Sec.dat contains fuse settings, mainly for secure boot and oem setting
splash The splash screen is displayed during the apps bootloader (also called the LK). The display driver in LK will read the splash image data from a separate eMMC partition named as ’splash’
aboot Partition for apps boot loader
abootbak Back up Partition for apps boot loader
boot This is the boot partition of your Android device,It includes the android kernel and the ramdisk.
recovery This is specially designed for backup. The recovery partition can be considered as an alternative boot partition
devinfo Device information including:iis_unlocked, is_tampered, is_verified, charger_screen_enabled, display_panel, bootloader_version, radio_version All these attirbutes are set based on some specific conditions and written on devinfo partition,.
system This partition contains the entire Android OS, other than the kernel and the ramdisk. This includes the Android GUI and all the system applications that come pre-installed on the device
cache This is the partition where Android stores frequently accessed data and app components
persist Partition entry for persist image. which contains data which shouldn’t be changed after the device shipped, for example: calibration data of chips(wifi, bt, camera, etc.), certificates and other security related files.
misc This partition contains miscellaneous system settings in form of on/off switches. These settings may include CID (Carrier or Region ID), USB configuration and certain hardware settings etc
keystore Partition for keystore service.
config Partition needed during display panel initialization. More info at Display_panel_configuration_in_Device_Tree
oem "It is meant for storing OEM specific info. Customer in this case can decide whether he wants to keep this partition or not typically reserved partitions are kept for future use
limits Partition to store LMh params on 8976 target. LMh (Limits management) driver in SBL writes the LMh HW trimmed data into separate partition and uses the same data for later reboots
mota Backup partition for M ota upgrade
devcfg Partition needed by TZ for M upgrades.
Dip Partition needed for SafeSwitch, feature (FR26255) designed to allow OEMs and carriers to address new smartphone theft bill issues.
mdtp Partition needed for SafeSwitch, feature (FR26255) designed to allow OEMs and carriers to address new smartphone theft bill issues.
userdata Partition for userdata image
cmnlib Verified boot feature introduced in M needLK to load cmnlib corresponding partitions
keymaster Verified boot feature introduced in M needs LK to load keymaster from corresponding partitions
syscfg Syscfg is internal testing for Vmin and CPR characterization
mcfg All MBNs place holder in flash. Specific MBN would be loaded by mcfg image based on the SIM/Carrier.
msadp used for modem debug policy
apdp used for persisting the debug policy. "Debug policy" is used to better support development and debug on secure/fuse-blown devices One instance of the debug policy will be signed for the AP
dpo This partition will store a policy override