▁ext 3 , ▁or ▁third ▁extended ▁filesystem , ▁is ▁a ▁journ aled ▁file ▁system ▁that ▁is ▁commonly ▁used ▁by ▁the ▁Linux ▁kernel . ▁It ▁used ▁to ▁be ▁the ▁default ▁file ▁system ▁for ▁many ▁popular ▁Linux ▁distributions . ▁Stephen ▁Twe ed ie ▁first ▁revealed ▁that ▁he ▁was ▁working ▁on ▁extending ▁ext 2 ▁in ▁Journal ing ▁the ▁Linux ▁ext 2 fs ▁Files ystem ▁in ▁a ▁ 1 9 9 8 ▁paper , ▁and ▁later ▁in ▁a ▁February ▁ 1 9 9 9 ▁kernel ▁ma iling ▁list ▁posting . ▁The ▁filesystem ▁was ▁merged ▁with ▁the ▁main line ▁Linux ▁kernel ▁in ▁November ▁ 2 0 0 1 ▁from ▁ 2 . 4 . 1 5 ▁on ward . ▁Its ▁main ▁advantage ▁over ▁ext 2 ▁is ▁journal ing , ▁which ▁impro ves ▁reli ability ▁and ▁elimin ates ▁the ▁need ▁to ▁check ▁the ▁file ▁system ▁after ▁an ▁un clean ▁shut down . ▁Its ▁successor ▁is ▁ext 4 . ▁ ▁Adv antages ▁The ▁performance ▁( speed ) ▁of ▁ext 3 ▁is ▁less ▁attract ive ▁than ▁compet ing ▁Linux ▁filesystem s , ▁such ▁as ▁ext 4 , ▁J FS , ▁Re iser FS , ▁and ▁X FS , ▁but ▁ext 3 ▁has ▁a ▁significant ▁advantage ▁in ▁that ▁it ▁allows ▁in - place ▁up gr ades ▁from ▁ext 2 ▁without ▁having ▁to ▁backup ▁and ▁restore ▁data . ▁Ben chmark s ▁suggest ▁that ▁ext 3 ▁also ▁uses ▁less ▁CPU ▁power ▁than ▁Re iser FS ▁and ▁X FS . ▁It ▁is ▁also ▁considered ▁sa fer ▁than ▁the ▁other ▁Linux ▁file ▁systems , ▁due ▁to