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|00000000| 46 72 6f 6d 20 6a 73 71 | 40 63 73 2e 75 74 65 78 |From jsq|@cs.utex|
|00000010| 61 73 2e 65 64 75 20 20 | 54 68 75 20 4a 61 6e 20 |as.edu  |Thu Jan |
|00000020| 31 37 20 30 31 3a 30 37 | 3a 35 37 20 31 39 39 31 |17 01:07|:57 1991|
|00000030| 0a 52 65 63 65 69 76 65 | 64 3a 20 66 72 6f 6d 20 |.Receive|d: from |
|00000040| 63 73 2e 75 74 65 78 61 | 73 2e 65 64 75 20 62 79 |cs.utexa|s.edu by|
|00000050| 20 75 75 6e 65 74 2e 55 | 55 2e 4e 45 54 20 28 35 | uunet.U|U.NET (5|
|00000060| 2e 36 31 2f 31 2e 31 34 | 29 20 77 69 74 68 20 53 |.61/1.14|) with S|
|00000070| 4d 54 50 20 0a 09 69 64 | 20 41 41 30 36 35 35 33 |MTP ..id| AA06553|
|00000080| 3b 20 54 68 75 2c 20 31 | 37 20 4a 61 6e 20 39 31 |; Thu, 1|7 Jan 91|
|00000090| 20 30 31 3a 30 37 3a 35 | 37 20 2d 30 35 30 30 0a | 01:07:5|7 -0500.|
|000000a0| 50 6f 73 74 65 64 2d 44 | 61 74 65 3a 20 31 35 20 |Posted-D|ate: 15 |
|000000b0| 4a 61 6e 20 39 31 20 32 | 31 3a 32 34 3a 31 31 20 |Jan 91 2|1:24:11 |
|000000c0| 47 4d 54 0a 52 65 63 65 | 69 76 65 64 3a 20 62 79 |GMT.Rece|ived: by|
|000000d0| 20 63 73 2e 75 74 65 78 | 61 73 2e 65 64 75 20 28 | cs.utex|as.edu (|
|000000e0| 35 2e 36 34 2f 31 2e 39 | 33 29 20 0a 46 72 6f 6d |5.64/1.9|3) .From|
|000000f0| 3a 20 72 6d 6c 40 68 70 | 66 63 64 63 2e 66 63 2e |: rml@hp|fcdc.fc.|
|00000100| 68 70 2e 63 6f 6d 20 28 | 42 6f 62 20 4c 65 6e 6b |hp.com (|Bob Lenk|
|00000110| 29 0a 4e 65 77 73 67 72 | 6f 75 70 73 3a 20 63 6f |).Newsgr|oups: co|
|00000120| 6d 70 2e 73 74 64 2e 75 | 6e 69 78 0a 53 75 62 6a |mp.std.u|nix.Subj|
|00000130| 65 63 74 3a 20 52 65 3a | 20 71 66 6f 72 6b 28 29 |ect: Re:| qfork()|
|00000140| 20 28 54 68 65 20 53 70 | 61 77 6e 20 6f 66 20 73 | (The Sp|awn of s|
|00000150| 70 61 77 6e 28 29 29 0a | 4d 65 73 73 61 67 65 2d |pawn()).|Message-|
|00000160| 49 64 3a 20 3c 31 36 39 | 39 36 40 63 73 2e 75 74 |Id: <169|96@cs.ut|
|00000170| 65 78 61 73 2e 65 64 75 | 3e 0a 52 65 66 65 72 65 |exas.edu|>.Refere|
|00000180| 6e 63 65 73 3a 20 3c 31 | 36 38 39 35 40 63 73 2e |nces: <1|6895@cs.|
|00000190| 75 74 65 78 61 73 2e 65 | 64 75 3e 0a 53 65 6e 64 |utexas.e|du>.Send|
|000001a0| 65 72 3a 20 6a 73 71 40 | 63 73 2e 75 74 65 78 61 |er: jsq@|cs.utexa|
|000001b0| 73 2e 65 64 75 0a 58 2d | 53 75 62 6d 69 73 73 69 |s.edu.X-|Submissi|
|000001c0| 6f 6e 73 3a 20 73 74 64 | 2d 75 6e 69 78 40 75 75 |ons: std|-unix@uu|
|000001d0| 6e 65 74 2e 75 75 2e 6e | 65 74 0a 44 61 74 65 3a |net.uu.n|et.Date:|
|000001e0| 20 31 35 20 4a 61 6e 20 | 39 31 20 32 31 3a 32 34 | 15 Jan |91 21:24|
|000001f0| 3a 31 31 20 47 4d 54 0a | 52 65 70 6c 79 2d 54 6f |:11 GMT.|Reply-To|
|00000200| 3a 20 73 74 64 2d 75 6e | 69 78 40 75 75 6e 65 74 |: std-un|ix@uunet|
|00000210| 2e 55 55 2e 4e 45 54 0a | 54 6f 3a 20 73 74 64 2d |.UU.NET.|To: std-|
|00000220| 75 6e 69 78 40 75 75 6e | 65 74 2e 55 55 2e 4e 45 |unix@uun|et.UU.NE|
|00000230| 54 0a 0a 53 75 62 6d 69 | 74 74 65 64 2d 62 79 3a |T..Submi|tted-by:|
|00000240| 20 72 6d 6c 40 68 70 66 | 63 64 63 2e 66 63 2e 68 | rml@hpf|cdc.fc.h|
|00000250| 70 2e 63 6f 6d 20 28 42 | 6f 62 20 4c 65 6e 6b 29 |p.com (B|ob Lenk)|
|00000260| 0a 0a 49 6e 20 61 72 74 | 69 63 6c 65 20 3c 31 36 |..In art|icle <16|
|00000270| 38 39 35 40 63 73 2e 75 | 74 65 78 61 73 2e 65 64 |895@cs.u|texas.ed|
|00000280| 75 3e 20 6a 66 68 40 72 | 70 70 33 38 36 2e 63 61 |u> jfh@r|pp386.ca|
|00000290| 63 74 75 73 2e 6f 72 67 | 20 28 4a 6f 68 6e 20 46 |ctus.org| (John F|
|000002a0| 20 48 61 75 67 68 20 49 | 49 29 20 77 72 69 74 65 | Haugh I|I) write|
|000002b0| 73 3a 0a 0a 3e 20 41 67 | 61 69 6e 2c 20 74 68 65 |s:..> Ag|ain, the|
|000002c0| 20 70 72 6f 62 6c 65 6d | 20 79 6f 75 20 61 72 65 | problem| you are|
|000002d0| 20 61 6c 6c 75 64 69 6e | 67 20 74 6f 20 72 65 73 | alludin|g to res|
|000002e0| 75 6c 74 73 20 66 72 6f | 6d 20 74 68 65 20 63 68 |ults fro|m the ch|
|000002f0| 6f 69 63 65 20 6f 66 20 | 65 61 72 6c 79 0a 3e 20 |oice of |early.> |
|00000300| 6f 72 20 6c 61 74 65 20 | 61 6c 6c 6f 63 61 74 69 |or late |allocati|
|00000310| 6f 6e 20 6f 66 20 70 61 | 67 69 6e 67 20 73 70 61 |on of pa|ging spa|
|00000320| 63 65 2e 20 20 49 66 20 | 79 6f 75 20 63 68 6f 6f |ce.  If |you choo|
|00000330| 73 65 20 65 61 72 6c 79 | 20 61 6c 6c 6f 63 61 74 |se early| allocat|
|00000340| 69 6f 6e 2c 20 79 6f 75 | 0a 3e 20 61 72 65 20 63 |ion, you|.> are c|
|00000350| 6f 72 72 65 63 74 20 2d | 20 79 6f 75 20 63 61 6e |orrect -| you can|
|00000360| 27 74 20 66 6f 72 6b 28 | 29 20 61 20 33 30 4d 42 |'t fork(|) a 30MB|
|00000370| 20 70 72 6f 63 65 73 73 | 20 77 69 74 68 20 6f 6e | process| with on|
|00000380| 6c 79 20 32 30 4d 42 20 | 72 65 6d 61 69 6e 69 6e |ly 20MB |remainin|
|00000390| 67 2e 0a 3e 20 41 6e 64 | 20 79 65 73 2c 20 69 66 |g..> And| yes, if|
|000003a0| 20 79 6f 75 20 63 68 6f | 6f 73 65 20 6c 61 74 65 | you cho|ose late|
|000003b0| 20 61 6c 6c 6f 63 61 74 | 69 6f 6e 20 69 74 20 69 | allocat|ion it i|
|000003c0| 73 20 70 6f 73 73 69 62 | 6c 65 20 74 6f 20 64 65 |s possib|le to de|
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|000003f0| 77 68 65 72 65 20 79 6f | 75 20 61 72 65 20 64 6f |where yo|u are do|
|00000400| 69 6e 67 20 6d 6f 72 65 | 20 74 68 61 6e 20 79 6f |ing more| than yo|
|00000410| 75 20 61 72 65 20 77 69 | 74 68 20 76 66 6f 72 6b |u are wi|th vfork|
|00000420| 28 29 2e 0a 0a 54 68 69 | 73 20 73 6f 75 6e 64 73 |()...Thi|s sounds|
|00000430| 20 6c 69 6b 65 20 61 20 | 67 6f 6f 64 20 61 72 67 | like a |good arg|
|00000440| 75 6d 65 6e 74 20 66 6f | 72 20 74 77 6f 20 6d 65 |ument fo|r two me|
|00000450| 63 68 61 6e 69 73 6d 73 | 2c 20 6f 6e 65 20 77 69 |chanisms|, one wi|
|00000460| 74 68 20 65 61 72 6c 79 | 0a 61 6c 6c 6f 63 61 74 |th early|.allocat|
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|00000480| 72 20 77 69 74 68 20 6c | 61 74 65 20 28 6f 72 20 |r with l|ate (or |
|00000490| 70 65 72 68 61 70 73 20 | 6e 6f 29 20 61 6c 6c 6f |perhaps |no) allo|
|000004a0| 63 61 74 69 6f 6e 2e 20 | 20 49 66 20 74 68 65 0a |cation. | If the.|
|000004b0| 4f 53 20 63 68 6f 6f 73 | 65 73 20 62 6c 69 6e 64 |OS choos|es blind|
|000004c0| 6c 79 20 66 72 6f 6d 20 | 61 20 73 69 6e 67 6c 65 |ly from |a single|
|000004d0| 20 69 6e 74 65 72 66 61 | 63 65 20 28 66 6f 72 6b | interfa|ce (fork|
|000004e0| 29 20 69 74 20 77 69 6c | 6c 20 73 6f 6d 65 74 69 |) it wil|l someti|
|000004f0| 6d 65 73 0a 63 68 6f 6f | 73 65 20 22 77 72 6f 6e |mes.choo|se "wron|
|00000500| 67 22 20 61 63 63 6f 72 | 64 69 6e 67 20 74 6f 20 |g" accor|ding to |
|00000510| 74 68 65 20 6e 65 65 64 | 73 20 6f 66 20 74 68 65 |the need|s of the|
|00000520| 20 61 70 70 6c 69 63 61 | 74 69 6f 6e 2e 20 20 54 | applica|tion.  T|
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|00000540| 20 69 6e 74 65 72 66 61 | 63 65 20 74 6f 20 73 65 | interfa|ce to se|
|00000550| 6c 65 63 74 20 74 68 65 | 20 62 65 68 61 76 69 6f |lect the| behavio|
|00000560| 72 20 6f 66 20 66 6f 72 | 6b 28 29 20 72 61 74 68 |r of for|k() rath|
|00000570| 65 72 20 74 68 61 6e 20 | 74 77 6f 0a 73 65 70 61 |er than |two.sepa|
|00000580| 72 61 74 65 20 63 61 6c | 6c 73 3b 20 74 68 65 72 |rate cal|ls; ther|
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|000005b0| 70 72 6f 61 63 68 2e 0a | 0a 49 6e 20 77 68 61 74 |proach..|.In what|
|000005c0| 20 49 27 76 65 20 72 65 | 61 64 20 69 6e 20 74 68 | I've re|ad in th|
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|000005e0| 6f 75 74 20 71 66 6f 72 | 6b 28 29 2c 20 49 27 6d |out qfor|k(), I'm|
|000005f0| 20 6e 65 72 76 6f 75 73 | 20 61 62 6f 75 74 0a 74 | nervous| about.t|
|00000600| 68 65 20 73 70 65 63 20 | 74 68 61 74 20 2a 6e 6f |he spec |that *no|
|00000610| 74 68 69 6e 67 2a 20 69 | 73 20 70 65 72 6d 69 74 |thing* i|s permit|
|00000620| 74 65 64 20 62 65 74 77 | 65 65 6e 20 69 74 20 61 |ted betw|een it a|
|00000630| 6e 64 20 65 78 65 63 2e | 20 20 49 66 20 6e 6f 74 |nd exec.|  If not|
|00000640| 68 69 6e 67 20 69 73 0a | 70 65 72 6d 69 74 74 65 |hing is.|permitte|
|00000650| 64 20 70 6f 72 74 61 62 | 6c 79 2c 20 74 68 65 6e |d portab|ly, then|
|00000660| 20 61 20 73 69 6e 67 6c | 65 20 73 70 61 77 6e 20 | a singl|e spawn |
|00000670| 63 61 6c 6c 20 73 68 6f | 75 6c 64 20 62 65 20 64 |call sho|uld be d|
|00000680| 65 66 69 6e 65 64 2e 20 | 20 54 68 65 0a 77 68 6f |efined. | The.who|
|00000690| 6c 65 20 61 64 76 61 6e | 74 61 67 65 20 6f 66 20 |le advan|tage of |
|000006a0| 73 65 70 61 72 61 74 65 | 20 63 61 6c 6c 73 20 69 |separate| calls i|
|000006b0| 73 20 74 68 61 74 20 74 | 68 69 6e 67 73 20 2a 63 |s that t|hings *c|
|000006c0| 61 6e 2a 20 62 65 20 64 | 6f 6e 65 20 69 6e 0a 62 |an* be d|one in.b|
|000006d0| 65 74 77 65 65 6e 2e 20 | 20 50 65 6f 70 6c 65 20 |etween. | People |
|000006e0| 77 69 6c 6c 20 74 61 6b | 65 20 61 64 76 61 6e 74 |will tak|e advant|
|000006f0| 61 67 65 20 6f 66 20 74 | 68 69 73 20 65 76 65 6e |age of t|his even|
|00000700| 20 69 66 20 74 68 65 20 | 73 74 61 6e 64 61 72 64 | if the |standard|
|00000710| 20 63 61 6c 6c 73 0a 74 | 68 65 20 62 65 68 61 76 | calls.t|he behav|
|00000720| 69 6f 72 20 69 6d 70 6c | 65 6d 65 6e 74 61 74 69 |ior impl|ementati|
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|00000760| 65 73 75 6c 74 20 69 73 | 20 74 68 61 74 20 70 65 |esult is| that pe|
|00000770| 6f 70 6c 65 20 77 69 6c | 6c 20 77 72 69 74 65 20 |ople wil|l write |
|00000780| 6c 65 73 73 2d 74 68 61 | 6e 2d 70 6f 72 74 61 62 |less-tha|n-portab|
|00000790| 6c 65 20 63 6f 64 65 2e | 20 20 49 66 20 74 68 65 |le code.|  If the|
|000007a0| 0a 73 74 61 6e 64 61 72 | 64 20 64 65 66 69 6e 65 |.standar|d define|
|000007b0| 73 20 71 66 6f 72 6b 28 | 29 2c 20 49 20 74 68 69 |s qfork(|), I thi|
|000007c0| 6e 6b 20 69 74 20 73 68 | 6f 75 6c 64 20 64 65 66 |nk it sh|ould def|
|000007d0| 69 6e 65 20 61 20 75 73 | 65 66 75 6c 20 73 65 74 |ine a us|eful set|
|000007e0| 20 6f 66 0a 6f 70 65 72 | 61 74 69 6f 6e 73 20 70 | of.oper|ations p|
|000007f0| 65 72 6d 69 74 74 65 64 | 20 77 69 74 68 20 77 65 |ermitted| with we|
|00000800| 6c 6c 2d 64 65 66 69 6e | 65 64 20 72 65 73 75 6c |ll-defin|ed resul|
|00000810| 74 73 20 69 6e 20 74 68 | 65 20 63 68 69 6c 64 20 |ts in th|e child |
|00000820| 70 72 69 6f 72 20 74 6f | 0a 65 78 65 63 2e 0a 0a |prior to|.exec...|
|00000830| 09 09 42 6f 62 20 4c 65 | 6e 6b 0a 09 09 72 6d 6c |..Bob Le|nk...rml|
|00000840| 40 66 63 2e 68 70 2e 63 | 6f 6d 0a 09 09 7b 75 75 |@fc.hp.c|om...{uu|
|00000850| 6e 65 74 2c 68 70 6c 61 | 62 73 7d 21 66 63 2e 68 |net,hpla|bs}!fc.h|
|00000860| 70 2e 63 6f 6d 21 72 6d | 6c 0a 0a 56 6f 6c 75 6d |p.com!rm|l..Volum|
|00000870| 65 2d 4e 75 6d 62 65 72 | 3a 20 56 6f 6c 75 6d 65 |e-Number|: Volume|
|00000880| 20 32 32 2c 20 4e 75 6d | 62 65 72 20 37 32 0a 0a | 22, Num|ber 72..|
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