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1 .A 'SENItI '...J:i,. t.. ' w /t<;rli JJ(TltuJ) pc.. Dik Rpo Tim Maurmt Thoma D. lohot loatha M. Smithtt Eric S. Wilot Columbia Uivrity Computr Scic Dpartmt 450 Computr Scic, Columbia Uivrity, NY, NY ClA-C S - ;)-;2.3 - f-6 ABSTRACT Thi papr d~crib r~ tim maurmt mad by irtig tracig cod i th UNIX Sytm dvic drivr for th Digital Equipmt Corporatio TM (DEC ') RA81 dik attachd to a DEC UDA50 cotrollr. Th goal ad mthodology of th maurmt ar dcribd. Dtaild aalyi of data drivd from th maurmt i providd, ad om cocluio ar draw about th ffct of UNIX fil ytm mchaim o rpo tim a by ur proc. t Bll Commuicatio Rarch. Ic. tt Thi work wa prfomld at Bll Commuicatio Rarch, Ic. UNIX i a rgitrd tradmark of AT&T. V AX, Digilal. UNIBUS. MASSBUS, m. UDASO, RP06, HSCSO. V AXClutr. RASI. DSA, ad DEC ar Tradmark of Digit.al qui pmdt Corpomio.

2 Dik Rpo Tim Maurmt Thoma D. Johot Joatha M. Smithtt Eric S. Wilot Columbia Uivrity Computr Scic Dpartmt 450 Computr Scic, Columbia Uivrity, NY, NY Itroductio Thi rport dcrib maurmt mad i th cour of a dik prformac tudy. Th maurmt dal with th rpo tim for acc rqut mad to th DEC RASI dik, a maurd o a ytm ud for gral-purpo tim-hard computig. Thi diffr from om prviou work[l) (2), much of which i dirctd toward maurig ad improvig fil ytm throughput Th papr aum a kowldg of UNIX Sytm V itral a dicud by Bach(3). 1.1 Equipmt Th tudy i of a pcific machi cofiguratio, which coit of a DEC V AX-IlS5 with S mgabyt of mai mmory; ma torag dvic ar attachd to a DEC UDA50 cotrollrl 4 ). Th aociatd dik hardwar i th DEC RASI dik driv; typical ytm hav four driv. Th RASI i a radom-acc, movig-had dik driv with o-rmovabl mdia. Th driv ha a data torag capacity of 456 mgabyt. Th prformac of th RASI hardwar i capulatd i th followig tabl, drivd from th RA81 Dik Driv Ur Guid[S): DEC RASI Dik Driv Charactritic Cylidr 2516 Trafr Rat 2.2 mgabyt/cod Rotatioal Spd 3600 rpm Avrag Rotatioal Latcy Had Switch Latcy Avrag Sk O Cylidr Sk Maximum Sk S.33 millicod 6 millicod 2S millicod 7 millicod 50 millicod Up to four RASI driv ca b coctd to th UDASO cotrollr; th UDA50 i a UNIBUS dvic. Th DEC UNIBUS ubytm itrfac to th Sychroou Bu Itrcoct (SBD through a UNIBUS Adaptr (UBA). Th UBA ca upport a maximum data trafr rat of oly 1.35 mgabyt/cod(6). Thu, th pak data trafr rat of th driv i ot ralizabl with thi cofiguratio. 1.2 Softwar Thi ctio dcrib ytm ad prformac maurmt oftwar availabl prviou to our tudy Opratig Sytm Our VAX Sytm oprat UNIX Sytm V Rla 2. Virtual mmory i achivd via wappig; pagig i ot ud i thi Rla. A upplid by AT&T Bll Laboratori, UNIX do ot hav a dvic drivr for th UDA50/RASl. Our cofiguratio wa origially opratioal uig a dvic drivr adaptd from a 4.2BSD drivr for th UDA50; th drivr' drivatio from 4.2BSD ld to th omiio of fatur for rportig prformac via th SAR(7) (8) ytm. SAR dik prformac rportig wa addd by a fw chag i th drivr. Each of our ytm ar cofigurd with 1000 buffr. t Bll Corruuicatio Rarch, Ic. tt Thi woc wa prfod at Bll Commuicatio Rarch, Ic.

3 Maurmt Tool Th maurmt tool which xitd prviou to thi tudy coitd maily of th variou pic of th SAR packag. Th iformatio providd by SAR wa iadquat for th purpo of d trmig th cau of poor rpo tim from our dik. Portig th dik activity rportig portio of SAR would rquir xtiv drivr updat, ad w flt that om bttr maurmt wr cary. 1.3 Tracig: Iitial Cofiguratio Svral goal wr clar at th outt: l. W dd a way to maur actual dik activity. rathr tha logical rad ad writ. 2. Th data gathrig hould ot cotamiat th maurmt; that i, it hould ot cau xtraou data to b gratd 1 3. Whil it may add a fw itructio to th rvic routi, th data gathrig tchiqu hould ot igificatly altr th prformac of th ubytm; othrwi timig data ar maigl. 4. It hould giv u ough auxiliary iformatio for furthr dtaild aalyi with othr tool. 5. Th obrvatio hould b idpdt of th drivr oftwar. Our approach wa to implmt a circular trac buffr of dik rqut. It wa ud to track rqut mad to th drivr through th udtralgy() routi 2 Th data gathrd ar a t from which w bliv much ca b drivd; thy ar packd ito a pair of 32 bit word; th icluio of ach datum i jutifid a follow: 1. RlW flag - High ordr bit of th firt rcord Thi wa origially ot icludd. but aftr prlimiary data gathrig wa complt, it wa clar that th dirctio of th VO wa importat (.g. for dtrmiig wappig charactritic) 2. Dvic umbr - 15 bit of a 16 bit quatity. I practic, all w d hr i th 8 bit mior dvic umb~, plu a bit to ditiguih btw charactr pcial ad block pcial acc; but it i air th way w do it 3. Timtamp - implmtd by uig th lat 16 bit of th Ibolt oftwar clock. LboU i a log itgr which i icrmtd upo ach clock: itrrupt ("tick"); it i icrmtd at 1160 cod itrval. Thi clock valu provid th mallt graularity with which w ca maur vt i oftwar 4 Thu w ca dtrmi th rat at which rqut ar quud, ad th itrval btw vt uch a burt of writig. 16 bit m ufficit; w could giv up a fw i th dvic umbr fild if mor m uful. 4. Siz of th rqut - thi i ot maigful for buffrd VO, ic all rqut will u th fil ytm block iz. It i uful i dtig th amout of VO prformd through th charactr pcial itrfac. W ud 8 bit bcau it i all w had to par i th cod 32-bit word; but ic MAXBLK i 125 o our ytm, it i ot a problm. Rqut largr tha MAXBLK ar th rult of abormal coditio (uch a a ytm admiitrator uig a hug blockig factor with dd(l» ad ar thrfor ot rlvat 1. E.g., by uig buff~ which could othrwi b allocatd. 2. Thi routi i calld to plac a buffr hadr oto th driv quu for th dvic. Oc a buffr hadr i placd o th driv quu, th aociatd acc will b prformd. Thu, placig th trlicig cod i udlraugy() ur that all dik acc will b dtctd. 3. Idicatig a itac of th dvic typ dtrmid by th fi~t 8 bit, th major dvic umbr. 4. W could, of co~, hav modifid th ytm' clock routi i ordr to achiv a fir graularity of maurmt, but thi would hav rquird may modificatio of th krl. 5. Th maximum iz rqut mad by th wappr i movig proc to ad from th dik dvic.

4 - 3 - S. Th block umbr - w ud 3 byt (24 bit) bcau that' ufficit to tor UNIX fil ytm dik addr. Thi block umbr i th block umbr rlativ to th bgiig of th fil ytm; th block umbr o th dvic ca b dtrmid off li by uig iformatio kpt i th ra_lic[] tructur dfid i ylio.h Buffr Implmtatio Th iformatio dcribd abov rquir two 32-bit word; w allocatd a 2048 try itgr array, givig u 1024 rcord. Giv th obrvd trafr rat of th block 110 ubytm, thi wa ufficit to captur all of th data. I additio, a itgr wa ud to track th currt idx of th array Gathrig W gathrd th rcord uig th itrfac to th krl's addr pac providd by /dv/kmm. Th addr of th trac buffr ad th currt idx wr obtaid uig th Ut() library routi. Data gathrig coitd of moitorig th idx variabl for ay chag; ay rcord btw chagd valu wr dumpd to th tadard output. Thi output wa rdirctd to th charactr pcial fil itrfac for a magtic tap dvic i ordr to miimiz itrfrc with th fil ytm Formattig Th rcord from th tap dvic wr formattd i a mar imilar to th tri i /tc/pas5'\'d; that i, a colo-dlimitd trig, o li pr rcord. Thi facilitatd th u of tool uch a grp ad d i aalyzig th data. For xampl, rcord dtid for th firt lic of th root dvic via th raw itrfac could b lctd uig grp. 1.4 Tracig: Fial Cofiguratio Th rmaidr of thi papr dicu th rult drivd from addig furthr tracig cod to th UDA50 drivr; thi cod trac both th rqut mad to th driv ad th rpo rcivd from it Th mthodology i dicud furthr i th ctio titld "Data Gathrig". W ca aalyz th rult of thi tracig to dtrmi th bhavior of th driv udr UNIX fil ytm activity. 2. Data Gathrig Thi ctio tak a "bottom-up" approach i dcribig how th data wa gathrd. By "bottom-up", w ma that th data gathrig i dicud bgiig at th lowt lvl (dvic drivr) ad dig at a dicuio of th tatitical aalyi prformd o formattd ad procd data. 2.1 Tracig I additio to th tracig dcribd abov, a circular trac buffr wa addd to th udrp() routi, which hadl rpo from th driv 6 W did ot attmpt to corrlat th rpo with th rqut at thi poit a w aticipatd that thi would b cotly i trm of drivr prformac Gathrig Trac Data Gathrig th trac data rquird a light modificatio of th data gathrig program. Th modificatio coitd of chckig both rqut ad rpo circular trac for w data ad writig out ay that wr foud. O problm with thi uophiticatd approach i that th data gratd do ot rtai it ordrig with rpct to tim 8 ; thi ha to b olvd latr wh rolvig th tim to grat rpo 6. Wh th driv ha compltd a opratio, it igal th CPU via th Uibu Adaptr (UBA). Th UBA i locatd at a kow itrrupt vctor; wh a itrrupt occur cauig a procor trap, th _Xuba routi hadl th trap by paig cotrol to th uduur() itrrupt hadlr for th UDASO. Thi routi xami th mag hadr aociatd with th itrrupt. ad if it i a rpo, pa cotrol to th udrp() routi. Not that thi procig i occurrig at a lttrmly high priority lvl, ad thu mut b rapid. 7. O driv uch a th RP06, corrlatio i trivial, a oly o rqut ca b outtadig, whil w ca hav up to 14 rqut outtadig o th RAS!. Th corrlatio would alo b trivial if w ud buffr hadr to cotai our trac data, but thi approach would b udirabl for vral rao. S. That i, a rpo might how up i th data tram ahad of th rqut which caud it

5 - 4 - tatluc. A w flag wa addd to th output i ordr to idicat whthr th rcord wa a "Sd" to th dvic, or a "Rciv" from th dvic. Th modifid program dtrmi thi by th trac buffr it i xamiig, ad output a itgr flag which th formattig program u to grat th appropriat rcord. Th rcord ar formattd: d/rciv flag: (major,mior) :iz:r/w flag:block umbr:timtamp Th iz ar i uit of 512 byt block: th tim tamp i providd by th lbolt ytm clock, mod Som ampl output (it i actual gathrd data, but abridgd for th ak of prtatio) follow: : (32,Ox10) :2:R:1984:22127 : (32,Ox10) :2:R:1992:22128 : (32,Ox6) :2:R:486502:22129 : (32,Oxll) :2:R:62782:22129 R: (32,Ox10) :2:R:1976:22123 R: (32,Ox10) :2:W:2152:22124 R: (32,Ox10) :2:W:2144:22124 R: (32,Ox10) :2:R:1984:22128 R: (32,Ox10) :2:R:1992:22130 R: (32,Oxll) :2:R:62782:2213l R: (32,Ox6) :2:R:486502:22132 R: (32,Ox6) :2:R:337822:22157 R: (32,Ox6) :2:R:339738:22158 : (32,Ox6) :2:R:337822:22156 : (32,Ox6) :2:R:339738:22157 Thi output ca b ud to illutrat vral of th problm o coutr wh tryig to grat rpo tim from th raw data, a dicud i th followig ctio. 2.3 Gratig Rpo Tim It tur out to b fairly ay to proc uch data viually: fid a rcord prcdd by a's', for a "Sd", ad th fid th matchig 'R', or "Rciv", rcord. Th diffrc btw thir timtamp giv th rpo tim for th rqut For xampl, th firt li of th ampl output i a's' rcord, for block umbr Th corrpodig 'R' i o th ighth li, ad w comput th rpo tim a ( ) tick, whr a tick i 1/60 cod. Thr ar, howvr, om pottial problm i th data tram. For xampl, thr ar o's' rcord corrpodig to th firt two 'R' rcord, ad th 'R' rcord for block o dvic (32,Qx6) prcd th's' rcord. It tur out that om huritic ar cary to gt aroud th corruptd tim-ordrig of th data tram; th huritic wr icorporatd ito a program to aalyz th data ad produc rpo tim figur o a pr-rqut bai. 2.4 Rpo Tim Statitic Thr ar vral output format availabl to th ur of th rpo tim aalyi program. O i ud to grat data for aalyi with th S ytm(9). Raw data wr collctd to obtai cout which could b ud i latr aalyi. Th firt fw li of uch a aalyi ar: 7480 rpo took 0 tick rpo took 1 tick rpo took 2 tick rpo took 3 tick rpo took 4 tick rpo took 5 tick rpo took 6 tick rpo took 7 tick rpo took 8 tick. 833 rpo took 9 tick.

6 - 5 - Th formattig of th data hlpd u i thi tak a it had i arlir aaly, bcau UNIX tool uch a grp ad d could b ud to aid th aalyi. For )<ampl, irtig uch a filtr ito th pipli cotaiig th rpo tim aalyzr allow u to aalyz rad ad writ paratly. 3. Data Aalyi Th amout of data gathrd wa trmdou; w moitord a ytm i our computr ctr for 3 hour o a aftroo i July, Th gathrd rcord took up about 6 mgabyt of pac; at 12 byt pr rcord. thi wa about 112 millio rcord. It i clar that automatd aalyi of th data i ot oly prfrabl, it i cary. Furthr, igl tatitic uch a th ma ad mdia[lo] do ot carry ough iformatio to b uful i ay o-trivial aalyi of th ytm. Graphical tchiqu, howvr, provid u with a mthodology which i both compact ad ufficitly iformativ. Oc a ubt of our data 9 wa trd ito S, w bga th aalyi. 3.1 Simpl Cout Th firt plottd data, prtd i Figur 1. i th umbr of rpo which took a pcifid umbr of tick. 9. Ufortuatly, du to mmory limitatio, w ar forcd to u oly th firt 2000 of our gathrd rcord to prform aalyi othr tha impl coutig. Thi ampl had o rpo takig logr tha 200 tick, ulik th largr ampl xamid for cootig tatitic. E.umialio of mor data lad u to th cocluio that our ampl i rprtativ, ad thu our cocluio ar tatitically valid.

7 N u m b 1000 r o f R p o r- \... \ **. 10 r- \ Numbr of Rpo v. Rpo tim _ rr- -,...- _...,... I " _, J u- ~ ~ L ~ o Rpo tim i tick Figur 1. # Rpo vru Rpo Tim W ca from thi data that mot of th rpo wr rcivd i 5 or l tick (ot that th y axi i logarithmic). Howvr, thr ar outlir i th gratr tha 300 tick rag, idicatig that om rqut ar ig vry bad rvic. Whil thi wo't affct th rpo tim of a proc prformig writ 10, rad will b affctd. a th proc caot cotiu util th data i dlivrd. For xampl, if o of th block which rquird 300 tick wa i th middl of a a.out fil big xcutd by om ur, that commad. howvr trivial, would rquir at lat fiv cod to bgi xcutig. 10. UNIX writ ar aychroou; th writ call rtur a oo a th data i trafrrd ito a ytm buffr. Th cott of thi ytm buffr will b 'W,;tt at om latr tim, ithr wh th ytm d th buffr or wh a rqut to yc th dik i iud.

8 Rpo By Driv Wh prformig dik load balacig, it i uful to kow which driv ar mor havily or lightly ud. Thu iformatio about th rpo tim a a fuctio of th driv may tll you which driv ar cadidat for xchagig om fil ytm. Rpo Tim v. Dvic Numbr 200 R * P I! T i m 100 I J * * I I l! I i i i 50 c * k i I * -r... 0 ± ~ ::c Dvic Numbr (0-2) * Figur 2. Rpo Tim vru Dvic Numbr (0-2) Thi graphll how that although th wort rpo tim ar xpricd by rqut o driv #1, th mdia of driv #0, driv #1, ad driv #2 ar fairly vly matchd. Thi v of th mdia idicat that for thi kid of fil ytm activity, th load by th driv i "balacd", idicatig that II. Thi paicular prtatio i calld a boxplot; it provid much mor iformatio tha a X Y plot for thi typ of data. For a giv x valu, th box dfi th middl 50 prct of th data, th horizotal li iid th box i th mdia, ad th bar at th d of th dahd li mari th art valu ot byod om tadard rag (i thi ca, l.s (itr-quartil rag» from th quartil. Poit outid th rag ar how idividually. Dtail of bolcp/ot prtatio ca b foud i Chambr, Qvlad, Klir, ad Tukytlll.

9 - 8 - th buy fil ytm ar apportiod wll btw th thr driv. Not, howvr, that th omwhat logr rpo tim for th top 50 prct of rqut o driv #2 may idicat om low; thi iformatio i lot if oly th mdia i xamid. If a particular driv or driv how uuual iquiti i rpo tim, it may prov uful to dtrmi which lic() of th driv() ar xpricig larg umbr of acc, ad prhap mov om of that activity to aothr driv. 3.3 Rpo by Block Numbr Rpo by block umbr ca tll u what ara of th dik ar "hot pot" - plac whr thr i a grat dal of activity. bilmo.pic Rpo Tim vru Driv #1 Block Numbr 200 Figur 3. Rpo Tim vru Block Numbr For xampl, th abov graph how that crtai ara of driv #1 xpric vry log rpo tim, ad that th ara ar wll-dfid 12 Som xamiatio ld to th dductio that th pik ar locatd

10 - 9 - at th i-lit of th fil ytm o driv #1. Th pik i rpo tim rult from a "yc" which cau may of th rqut to occur i a larg clutr. 3.4 Dvic Typ Th charactr pcial or "raw" itrfac provid a ma by which trafr of a arbitrary iz ca b accomplihd: for xampl, wap va. Th rpo tim by raw I/O rqut ca tll you whthr th dik trafr ratd or th tim pt i th driv quu i th major ourc of dlay xpricd by proc big wappd i. Rpo Tim v. Dvic Typ 200 Dvic Typ Figur 4. Rpo Tim vru Dvic typ (block",o.raw",l) 12. Th iz of a lic i block. 13. Although mor about th dil trafr rat ca b dducd from th trafr iz. a dicud i th xt ctio.

11 - 10- W from th data that trafr to ad from th raw dvic xpric good rpo tim. ad thu wap occur rlativly rapidly. Du to th rathr mall iz of thi data ampl. w did ot xpric a wap rqut itrmigld with data trafr caud by a "yc". whr th quud buffr which hav b writt ito ar actually trafrrd to th dikl4. Such a rqut may hav how xtrmly poor rpo tim. 3.5 Trafr Siz Th trafr iz (i block) plottd agait th rpo tim giv om maur of th cotributio of th dvic badwidth vru th quuig dlay xpricd by a rqut. If th dvic pd wa rpoibl for much of th dlay. larg rqut hould tak much logr tha mallr rqut. R/X> Tim v. Siz i Block 200 R p T i 100 m j I i c k * * Block Cout Figur S. Rpo Tim vru Trafr Siz (block) 14. UpdatO i th krl routi calld wh th ytm call yco i xcutd by om proc.!bi/yc i typically thi proc.

12 A ca b from th graph, thr m to b littl, if ay. rlatio btw trafr iz ad rpo tim. Thi idicat that th tim pt i th driv quu i mor igificat i it ffct o rpo tim tha th iz of th trafr (which i dirctly rlatd to dik badwidth). 3.6 Trafr Typ Thr ar two trafr typ. rad ad writ. It i itrtig to what rpo tim ar xpricd by th diffrt typ of rqut. Rpo Tim v. Rad/Writ 200 R P 0 T m i -.- i 50 c k ; 0 --'- t I T 0 1 Writ=O Rad= 1 Figur 6. Rpo Tim vru Trafr Typ It m clar from th graph that writ i gral m to xpric a logr rpo tim tha rad, although thr ar a fw rad which tak a log tim to complt. Th xplaatio for thi i quit impl: writ to block dvic oly happ a th rult of buffr big fluhd du to a hortag or du to a "yc" big xcutd. Th both rult i a larg umbr of writ rqut big by th dik drivr i a hort tim priod. Th cogtio caud by thi bhavior rult i may writ rqut xhibitig a xtrmly larg rpo tim. Som furthr aalyi ha how that th rad rqut which xhibit larg rpo tim ar tho which ar quud for th driv i a particular itrval. Th itrval occur hortly aftr a "yc" ha b iitiatd. Thu, rad quud i thi itrval mut wait for th larg prcdig

13 quu of writ to b fiuhd 1S 3.7 Start Tim Th rpo tim of a rqut plottd agait th tart tim ca tll you if thr ar tim-rlatd vt occurig which ca affct th rpo tim by dik rqut. Rpo Tim v. Start Tim R ; p j f T i 100 m i 50 c k 0 " Start Tim Figur 7. Rpo Tim vru Sta Tim Thi particular plot how a widow of about 3000 tick of tim; th tim valu wr obtaid from th lat igificat 16 bit of th ytm Ibolt timr. It m obviou that thr i om vt which i cauig th larg "pik" i rpo tim i th graph. Thi vt i a "yc". Ay rqut which ar quud i th am tim fram a th "yc" ar 15. Rqut ar ot rordrd by th drivr oftwar. a th hardwar provid k optimizatio.

14 affctd by it; i particular rad rqut ar potpod util th prcdig writ rqut ar atifid. 3.8 Cocluio Th data which w hav aalyzd hav how that th dvic thmlv ar ot particularly low!6. What m to mot affct th rpo tim of rad rqut i thir timig with rlatio to th larg block of writ rqut gratd by a "yc". Sic writ ar alrady aychroou, ad itractiv rpo tim i havily dpdt o rad rpo, it would m that proc tryig to rad data wh uch a block of writ rqut appar will uffr with rpct to rpo tim. Prhap om chma uch a "dribblig" th writ at th dik 17, rathr tha buchig thm up, could allviat th problm to om dgr. Othr uggtio iclud prioritizig rad, but thi may ivolv a grat dal of procig i ordr to prrv data coitcy!8. Howvr, ay tratgy mut b xamid by carfully ttig rpo tim charactritic of th ytm both bfor ad aftr th tratgy i implmtd, for xampl i th mar of McKuick, t al[(2). 4. Summary W hav dmotratd a ffctiv mthodology for tracig dik rqut, ad drivig rpo tim data from thi trac iformatio. Th rpo tim data ha b aalyzd ad corrlatd with othr trac data to yild a fuhr udrtadig of th bhavior of th UNIX Sytm V RI. 2 fil ytm with rpct to th DEC RA81 dik. I particular, w hav that th mchaim ud to fluh th fil ytm buffr cach ("yc") ca hav a grat ffct o th rpo tim of rad opratio, which ar ychroou. Thi ca, i tum, icra th variac by a ur i th ytm' rpo tim. W mad vral uggtio for furthr xploratio. 5. Ackowldgmt L.E. Boai, A.M. Gro, 1. Ahmad, ad T. Liu mad uggtio which gratly improvd a arlir vrio of thi papr. KJ. Buch' uggtio lad to vral improvmt i thi papr. Rmaiig fault ar our alo. 16. Th obrvatio mut b mad, howvr, that a timr with a rolutio o th ordr of 20 millicod i iadquat for loggig traactio takig plac at th pd of th dik trafr. For xampl, a rlativly larg prctag of rqut xhibitd rpo tim of 0 ticl; it i clar that w ar loig iformatio. 17. For xampl, ic th buffr cach i maitaid a a LRU lit, w ca aily lct om umbr of th "lat rctly wriu" block for quuig to th driv. Thi could b do with om mchaim uch a th callout tabl which provid a way to chdul priodic activiti iid th UNIX krl. 18. Icoitcy ca aily b gratd by rordrig dik rqut, i particular, by puttig a rad i frot of a writ for th am block

15 REFERENCES 1. A Fat Fil Sytmfor UNIX Marhall Kirk McKuick. William N. Joy. Samul J. Lfflr, Robrt S. Fabry Computr Sytm Rarch Group Tchical Rport #7. Computr Scic Diviio Dpartmt of Elctrical Egirig ad Computr Scic Uivrity of Califoria, Brkly July 27, Prformac Effct of Dik Subytm Choic for V AX Sytm Ruig 4.2BSD UNIX Bob Kridl ad Marhall Kirk McKuick Computr Sytm Rarch Group Tchical Rport #8. Computr Scic Diviio Dpartmt of Elctrical Egirig ad Computr Scic Uivrity of Califoria, Brkly July 27, Th Dig of th UNIX Opratig Sytm, Mauric J. Bach Prtic-Hall UDA50 Ur Guid EK-UDASO-UG-003 Digital Equipmt Corporatio 5. RA8l Dik Driv Ur Guid EK-ORA81-UG-OOI Digital Equipmt Corporatio 6. VAX Hardwar Hadbook ( ) Digital Equipmt Corporatio, Ordr Cod EB Th UNIX Sytm Activity Packag Tyh-W Pao Bll Tlpho Laboratori MF March 13, Th UNIX Sytm Activity Packag - UNIX 4.0 Tyh-W Pao Bll Tlpho Laboratori MF Jauary 6, S - A Itractiv Eviromtfor Data Aalyi ad Graphic Richard A. Bckr Joh M. Chambr Wadworth StatiticlProbabiJity Sri Itroductio to Statitic, Hrbrt Robbi ad Joh Va Ryzi, SRA, Graphical Mthod for Data Aalyi, Joh M. Chambr, William S. Clvlad, Bat Klir, ad Paul A. Tuky Duxbury Pr 1983

16 Maurig ad ImproYig th Prformac of Brkly UNIX Marhall Kirk McKuick, Samul J. Lffir, Michal J. Karl, Lui Flip Cabrra Computr Sytm Rarch Group Computr Scic Diviio Dparttt of Elctrical Egirig ad Computr Scic Uivrity of Califoria, Brkly Novmbr 30, 1985