While ROAMING AROUND IN ANDROID FORUMS AND THREADS , u came across words like GSI’s , AIO , TREBLE , but u dont know what accurately is the meaning of these , then u came to the right place . Here we gonna KNOW what the HECK ! actually TREBLE IS —(in simple English)
So from the very beginning , till ANDROID NOUGAT (7.0) ,all device were released with partitions including DALVIK/ART CACHE , BOOT ,SYSTEM , DATA ,CACHE( only in A only devices){HECK, NOW WHAT IS THIS, “A ONLY” AND “A/B” PARTITION , DONT WORRY ! GONNA EXPLAIN IN MY NEXT BLOG}
but after ANDROID OREO (8.0/8.1) everything changed , a new individual partition came “vendor” ,basically all oems and google wanted to ship OTA updates like security patches from google ,as fast as possible to END USERS ,
but after releasing from google, oems needed to wait for their chipset providers to update their code and then only they could release the final ota , so for eliminating this waiting time , treble came which actually seperates all this low level code{cosisting of modem firmware, hardware drivers}, from original operating system , so now an ota could be released without including that low level code ,as those became two individual foundations which can be updated independently(for conceptual clearity see following image).
NEED OF PROJECT TREBLE?
TREBLE should
dramatically speed up the update process—in theory, at least. Updating devices will still be in the manufacturer’s hands, but they have the independence of shipping ota as soon as google releases their code {however this didnt became reality everywhere}
EFFECT OF TREBLE IN COMMUNITY OF CUSTOM ROMs!
Treble brought the new era of GSI’s and even PORTED OEM OS ,all of the gsis and ported oem os can be found on xda forums under project treble category.GSI’s are hit as they are universal in nature 
, if a device has a compatible vendor (which is device specific) then any gsi can be flashed with that vendor , and this made android developers work somewhat easy as they now can maintain 1 gsi which can be run on any treble compatible device and even some non treble device are repartitioned unofficialy to support project treble , one example is MI A1 .
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