ファイルシステムの歴史: ジャーナリング編

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1. ϑΝΠϧγεςϜͷྺ࢙: δϟʔ φϦϯάฤ Naohiro Aota (@naota344)
2. ࣗݾ঺հ ໊લ: ੨ా௚େ ͓͋ͨͳ͓ͻΖ @naota344 ܚጯٛक़େֶͰϑΝΠϧγεςϜͷݚڀ Gentoo ίϛολ झຯ: FS Λյͨ͠ਓͷإ͕ݟ͍ͨ
3. ࠷ۙͷ͜ͱ: btrfsck Λ͔͚ͯͨ
4. ࡢ೔ btrfsck ͷதͷਓ͔ Βϝʔϧ͕དྷͨ
5. ࡢ೔ btrfsck ͷதͷਓ͔ Βϝʔϧ͕དྷͨ ۙ೔ patch ͕౤ߘ༧ఆ! ͩͦ͏Ͱ͢
6. ຊ೔ͷ͓୊ δϟʔφϦϯάͷྺ࢙
7. δϟʔφϦϯά ͖ͯͱʔʹ FS ʹॻ͘ͱ FS ͸յΕΔ Ұ؏ੑΛ࣋ͬͯॻ͘΂͖มߋ͕த్൒୺ʹͳͬ ͯյΕΔ δϟʔφϦϯά Ұ౓δϟʔφϧྖҬʹ͜Ε͔Βॻ͘಺༰Λࣄલ ʹॻ͘ δϟʔφϧॻ͖ऴΘΔ -> ຊମʹॻ͖͜Έ ్தͰࢮΜͰ΋େৎ෉ ͍ΘΏΔ write-ahead-logging
8. δϟʔφϦϯάॳग़ Reimplementing the Cedar file system using logging and group commit Robert Hagmann Xerox PARC 1987 ೥ Dorado, Dandelion ্Ͱಈ͍͍ͯͨ Cedar Λ Dragon ʹҠ২͢Δʹ͋ͨͬͯʮδϟʔφϦϯάʯ ͕௥Ճ͞Εͨ
9. Cedar, Dorado, Dandelion, Dragon Cedar ϓϩάϥϛϯάݴޠͷ໊લ ͔ͭ, Cedar ͕ಈ࡞͢Δʮϓϩάϥϛϯά؀ڥʯ ͷ໊લ Dorado, Dandelion D-Machine, Lisp Ϛγϯ Dorado 24bit ͱ͍͏ large virtual address space 1024x808 ͷ large Ͱ high-resolution ͳനࠇσΟε ϓϨΠ ࠷େ 32MB ͷ෺ཧσΟεΫ
10. લδϟʔφϦϯά࣌୅: TridentσΟε Ϋ Dorado, Dandelion ͸ Trident σΟεΫΛ࢖༻ http://www.computerhistory.org/ collections/catalog/102681543 Image courtesy of Computer History Museum
11. TridentσΟεΫ Trident disk for the Alto (1979) Trident σΟεΫͷඪ४తͳϑΥʔϚοτ͕ॻ͍ ͍ͯΔ ֤τϥοΫ (10080 words) = 9 ηΫλ x 1120 words ηΫλ͕ 3 ͭͷ෦෼ʹ෼͚ΒΕΔ ϔομ (2 words) ͦͷηΫλͷσΟεΫΞυϨε͕ॻ͍ͯ͋Δ ίϯτϩʔϥ͕ݕࠪ͢Δ ϥϕϧ (10 words) store file dependent information σʔλຊମ (1024 words) ֤ηΫλʹʮϥϕϧʯ͕෇͚ΒΕΔ
12. δϟʔφϦϯάҎલͷCedar File Name Table ͸ B-tree FS ্ͷશͯͷ file ͷ໊લͱ header ৘ใΛอ࣋ ϥϕϧΛ༻͍ͨҰ؏ੑอূ uid, page number page type (header, free, data) ͕ه࿥͞ΕΔ
13. FSD (File System for Dragon)
14. ͦͷଞ ࠓ೔͸ FS յΕͯͳ͍͚Ͳɺ εϥΠυॻ ͨ͘Ίͷ Emacs ͕ SEGV Ͱىಈ͠ͳ ͔ͬͨΓɺԿ౓΋࿈ଧͯͨ͠Βٸʹىಈ ͯ͠Έ͍ͨͳײ͡ʹͳΓ·ͨ͠
15. ͳΜͰ? emacs/src/xfns.c XGetICValues X ͷ input context ͷ৘ใͱͬͯ͘Δ Τϥʔͩͱ࠷ॳͷͱΕͳ͔ͬͨଐੑ໊͕ฦΔ attr = XVaCreateNestedList (0, XNAreaNeeded, &needed, NULL); XGetICValues (xic, XNStatusAttributes, attr, NULL); XFree (attr); if (needed->width == 0) { attr = XVaCreateNestedList (0, XNArea, &needed, NULL); XGetICValues (xic, XNStatusAttributes, attr, NULL); XFree (attr); } ʜ XFree (needed); <- ͜͜ͰࢮΜͰΔ
16. ͦΓΎʔ͠ΐΜ ͳΜͰଐੑऔಘΤϥʔʹͳͬͯͨ? imsettings ͷ͍ͤͬΆ͍: imsettings = ͍ΖΜͳ IM ͷڞ௨ϨΠϠʹ͓Ε͕ͳΔ! uim ͱ͔ fcitx Λಈతʹม͑ΒΕΔͥ! ͦΓΎʔ͠ΐΜ XMODIFIERS=@im=fcitx emacs XMODIFIERS= emacs
17. ·ͱΊ δϟʔφϦϯάͷ࿩Λੲ͔Βࠓ·Ͱͬ͘͞ͱ ͨ͠ imsettings ͸ͩΊͩ