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This file was processed as: Mailbox/MIME Entity
(archive/mbox).
Confidence | Program | Detection | Match Type | Support
|
---|
100%
| dexvert
| Mailbox/MIME Entity (archive/mbox)
| magic
| Supported |
100%
| dexvert
| Internet Message Format (text/imf)
| magic
| Supported |
1%
| dexvert
| Text File (text/txt)
| fallback
| Supported |
100%
| file
| Mailbox text, 1st line "From jsq@cs.utexas.edu Thu Jan 31 18:57:36 1991", ASCII text
| default
| |
100%
| TrID
| E-Mail message (Var. 2)
| default
| |
100%
| checkBytes
| Printable ASCII
| default
| |
100%
| perlTextCheck
| Likely Text (Perl)
| default
| |
100%
| siegfried
| x-fmt/111 Plain Text File
| default
| |
100%
| detectItEasy
| Format: plain text[LF]
| default (weak)
| |
100%
| xdgMime
| application/mbox
| default
|
|
hex view+--------+-------------------------+-------------------------+--------+--------+
|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| 33 31 20 31 38 3a 35 37 | 3a 33 36 20 31 39 39 31 |31 18:57|:36 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 75 | 75 2e 6e 65 74 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 32 30 38 35 37 |MTP ..id| AA20857|
|00000080| 3b 20 54 68 75 2c 20 33 | 31 20 4a 61 6e 20 39 31 |; Thu, 3|1 Jan 91|
|00000090| 20 31 38 3a 35 37 3a 33 | 36 20 2d 30 35 30 30 0a | 18:57:3|6 -0500.|
|000000a0| 50 6f 73 74 65 64 2d 44 | 61 74 65 3a 20 33 31 20 |Posted-D|ate: 31 |
|000000b0| 4a 61 6e 20 39 31 20 31 | 30 3a 30 35 3a 33 36 20 |Jan 91 1|0:05:36 |
|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 64 6f 6d 6f 40 74 | 73 61 2e 63 6f 2e 75 6b |: domo@t|sa.co.uk|
|00000100| 20 28 44 6f 6d 69 6e 69 | 63 20 44 75 6e 6c 6f 70 | (Domini|c Dunlop|
|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 61 67 61 69 6e 29 | 0a 4d 65 73 73 61 67 65 | (again)|.Message|
|00000150| 2d 49 64 3a 20 3c 31 37 | 35 32 37 40 63 73 2e 75 |-Id: <17|527@cs.u|
|00000160| 74 65 78 61 73 2e 65 64 | 75 3e 0a 52 65 66 65 72 |texas.ed|u>.Refer|
|00000170| 65 6e 63 65 73 3a 20 3c | 31 36 39 39 32 40 63 73 |ences: <|16992@cs|
|00000180| 2e 75 74 65 78 61 73 2e | 65 64 75 3e 20 3c 31 37 |.utexas.|edu> <17|
|00000190| 30 31 30 40 63 73 2e 75 | 74 65 78 61 73 2e 65 64 |010@cs.u|texas.ed|
|000001a0| 75 3e 20 3c 31 37 34 30 | 32 40 63 73 2e 75 74 65 |u> <1740|2@cs.ute|
|000001b0| 78 61 73 2e 65 64 75 3e | 0a 53 65 6e 64 65 72 3a |xas.edu>|.Sender:|
|000001c0| 20 6a 73 71 40 63 73 2e | 75 74 65 78 61 73 2e 65 | jsq@cs.|utexas.e|
|000001d0| 64 75 0a 52 65 70 6c 79 | 2d 54 6f 3a 20 64 6f 6d |du.Reply|-To: dom|
|000001e0| 6f 40 74 73 61 2e 63 6f | 2e 75 6b 0a 4f 72 67 61 |o@tsa.co|.uk.Orga|
|000001f0| 6e 69 7a 61 74 69 6f 6e | 3a 20 54 68 65 20 53 74 |nization|: The St|
|00000200| 61 6e 64 61 72 64 20 41 | 6e 73 77 65 72 20 4c 74 |andard A|nswer Lt|
|00000210| 64 2e 0a 58 2d 53 75 62 | 6d 69 73 73 69 6f 6e 73 |d..X-Sub|missions|
|00000220| 3a 20 73 74 64 2d 75 6e | 69 78 40 75 75 6e 65 74 |: std-un|ix@uunet|
|00000230| 2e 75 75 2e 6e 65 74 0a | 44 61 74 65 3a 20 33 31 |.uu.net.|Date: 31|
|00000240| 20 4a 61 6e 20 39 31 20 | 31 30 3a 30 35 3a 33 36 | Jan 91 |10:05:36|
|00000250| 20 47 4d 54 0a 54 6f 3a | 20 73 74 64 2d 75 6e 69 | GMT.To:| std-uni|
|00000260| 78 40 75 75 6e 65 74 2e | 75 75 2e 6e 65 74 0a 0a |x@uunet.|uu.net..|
|00000270| 53 75 62 6d 69 74 74 65 | 64 2d 62 79 3a 20 64 6f |Submitte|d-by: do|
|00000280| 6d 6f 40 74 73 61 2e 63 | 6f 2e 75 6b 20 28 44 6f |mo@tsa.c|o.uk (Do|
|00000290| 6d 69 6e 69 63 20 44 75 | 6e 6c 6f 70 29 0a 0a 49 |minic Du|nlop)..I|
|000002a0| 6e 20 61 72 74 69 63 6c | 65 20 3c 31 37 34 30 32 |n articl|e <17402|
|000002b0| 40 63 73 2e 75 74 65 78 | 61 73 2e 65 64 75 3e 20 |@cs.utex|as.edu> |
|000002c0| 6d 69 63 68 61 65 6c 40 | 43 53 2e 55 43 4c 41 2e |michael@|CS.UCLA.|
|000002d0| 45 44 55 20 28 6d 69 63 | 68 61 65 6c 20 67 65 72 |EDU (mic|hael ger|
|000002e0| 73 74 65 6e 29 20 77 72 | 69 74 65 73 3a 0a 3e 20 |sten) wr|ites:.> |
|000002f0| 4d 61 79 20 49 20 68 75 | 6d 62 6c 79 20 61 73 6b |May I hu|mbly ask|
|00000300| 20 77 68 61 74 20 77 61 | 73 20 77 72 6f 6e 67 20 | what wa|s wrong |
|00000310| 77 69 74 68 20 76 66 6f | 72 6b 3f 0a 0a 59 75 70 |with vfo|rk?..Yup|
|00000320| 2e 20 20 49 27 6c 6c 20 | 68 75 6d 62 6c 79 20 74 |. I'll |humbly t|
|00000330| 72 79 20 74 6f 20 61 6e | 73 77 65 72 2e 0a 3e 20 |ry to an|swer..> |
|00000340| 0a 3e 20 41 73 20 49 20 | 75 6e 64 65 72 73 74 61 |.> As I |understa|
|00000350| 6e 64 20 69 74 2c 20 76 | 66 6f 72 6b 27 73 20 73 |nd it, v|fork's s|
|00000360| 65 6d 61 6e 74 69 63 73 | 20 77 61 73 20 61 20 76 |emantics| was a v|
|00000370| 69 72 74 75 61 6c 20 66 | 6f 72 6b 2d 2d 0a 3e 20 |irtual f|ork--.> |
|00000380| 63 6f 6e 63 65 70 74 75 | 61 6c 6c 79 20 74 77 6f |conceptu|ally two|
|00000390| 20 65 78 65 63 75 74 69 | 6f 6e 20 74 68 72 65 61 | executi|on threa|
|000003a0| 64 73 20 77 6f 75 6c 64 | 20 72 65 74 75 72 6e 20 |ds would| return |
|000003b0| 66 72 6f 6d 20 74 68 65 | 20 63 61 6c 6c 2c 0a 3e |from the| call,.>|
|000003c0| 20 61 6e 64 20 74 68 65 | 79 20 6d 61 79 20 6f 72 | and the|y may or|
|000003d0| 20 6d 61 79 20 6e 6f 74 | 20 62 65 20 73 68 61 72 | may not| be shar|
|000003e0| 69 6e 67 20 64 61 74 61 | 20 73 70 61 63 65 2d 2d |ing data| space--|
|000003f0| 61 6e 79 20 70 72 6f 67 | 72 61 6d 0a 3e 20 74 68 |any prog|ram.> th|
|00000400| 61 74 20 72 65 6c 69 65 | 64 20 6f 6e 20 6f 6e 65 |at relie|d on one|
|00000410| 20 6f 72 20 74 68 65 20 | 6f 74 68 65 72 20 77 61 | or the |other wa|
|00000420| 73 20 62 79 20 64 65 66 | 69 6e 69 74 69 6f 6e 20 |s by def|inition |
|00000430| 62 72 6f 6b 65 6e 2e 0a | 0a 54 68 65 20 70 72 6f |broken..|.The pro|
|00000440| 62 6c 65 6d 20 2d 2d 20 | 6f 6e 65 20 70 72 6f 62 |blem -- |one prob|
|00000450| 6c 65 6d 20 2d 2d 20 69 | 73 20 69 6e 20 63 6f 6d |lem -- i|s in com|
|00000460| 69 6e 67 20 75 70 20 77 | 69 74 68 20 61 20 60 60 |ing up w|ith a ``|
|00000470| 70 6f 72 74 61 62 6c 65 | 27 27 0a 64 65 66 69 6e |portable|''.defin|
|00000480| 69 74 69 6f 6e 20 6f 66 | 20 60 60 64 61 74 61 20 |ition of| ``data |
|00000490| 73 70 61 63 65 27 27 2e | 20 20 4f 6e 20 77 68 61 |space''.| On wha|
|000004a0| 74 20 77 65 20 63 75 72 | 72 65 6e 74 6c 79 20 61 |t we cur|rently a|
|000004b0| 73 73 75 6d 65 20 74 6f | 20 62 65 0a 60 60 76 61 |ssume to| be.``va|
|000004c0| 6e 69 6c 6c 61 20 66 6c | 61 76 6f 75 72 27 27 20 |nilla fl|avour'' |
|000004d0| 61 72 63 68 69 74 65 63 | 74 75 72 65 73 20 73 75 |architec|tures su|
|000004e0| 63 68 20 61 73 20 74 68 | 61 74 20 6f 66 20 74 68 |ch as th|at of th|
|000004f0| 65 20 36 38 30 30 30 20 | 77 68 69 63 68 20 79 6f |e 68000 |which yo|
|00000500| 75 0a 63 69 74 65 2c 20 | 69 74 27 73 20 66 61 69 |u.cite, |it's fai|
|00000510| 72 6c 79 20 6f 62 76 69 | 6f 75 73 2e 20 20 42 75 |rly obvi|ous. Bu|
|00000520| 74 20 6f 6e 20 6f 74 68 | 65 72 73 2c 20 69 74 27 |t on oth|ers, it'|
|00000530| 73 20 6e 6f 74 2e 20 20 | 57 68 61 74 20 61 62 6f |s not. |What abo|
|00000540| 75 74 0a 72 65 67 69 73 | 74 65 72 73 3f 20 20 41 |ut.regis|ters? A|
|00000550| 72 65 20 74 68 65 79 20 | 64 61 74 61 20 73 70 61 |re they |data spa|
|00000560| 63 65 3f 20 20 4e 6f 3f | 20 20 45 76 65 6e 20 6f |ce? No?| Even o|
|00000570| 6e 20 61 72 63 68 69 74 | 65 63 74 75 72 65 73 20 |n archit|ectures |
|00000580| 77 69 74 68 0a 72 65 67 | 69 73 74 65 72 20 77 69 |with.reg|ister wi|
|00000590| 6e 64 6f 77 73 20 77 68 | 69 63 68 20 6d 61 79 20 |ndows wh|ich may |
|000005a0| 6f 72 20 6d 61 79 20 6e | 6f 74 20 6d 61 70 20 6f |or may n|ot map o|
|000005b0| 6e 74 6f 20 6d 61 69 6e | 20 6d 65 6d 6f 72 79 20 |nto main| memory |
|000005c0| 61 64 64 72 65 73 73 65 | 73 3f 0a 42 65 61 72 20 |addresse|s?.Bear |
|000005d0| 69 6e 20 6d 69 6e 64 20 | 74 68 61 74 20 73 75 63 |in mind |that suc|
|000005e0| 68 20 65 78 6f 74 69 63 | 61 20 61 72 65 20 6e 6f |h exotic|a are no|
|000005f0| 74 20 73 6f 20 65 78 6f | 74 69 63 20 61 6e 79 20 |t so exo|tic any |
|00000600| 6d 6f 72 65 3a 20 52 49 | 53 43 73 20 75 73 65 0a |more: RI|SCs use.|
|00000610| 74 68 65 6d 20 77 69 64 | 65 6c 79 2e 0a 0a 49 74 |them wid|ely...It|
|00000620| 20 73 65 65 6d 73 20 74 | 68 61 74 20 61 6e 79 20 | seems t|hat any |
|00000630| 64 65 66 69 6e 69 74 69 | 6f 6e 20 77 68 69 63 68 |definiti|on which|
|00000640| 20 69 73 20 73 61 66 65 | 20 6f 6e 20 61 6c 6c 20 | is safe| on all |
|00000650| 61 72 63 68 69 74 65 63 | 74 75 72 65 73 20 69 73 |architec|tures is|
|00000660| 0a 6c 69 61 62 6c 65 20 | 74 6f 20 63 6f 6e 73 74 |.liable |to const|
|00000670| 72 61 69 6e 20 77 68 61 | 74 20 6f 6e 65 20 6d 61 |rain wha|t one ma|
|00000680| 79 20 64 6f 20 62 65 74 | 77 65 65 6e 20 5b 71 76 |y do bet|ween [qv|
|00000690| 5d 66 6f 72 6b 28 29 20 | 61 6e 64 20 65 78 65 63 |]fork() |and exec|
|000006a0| 28 29 20 73 6f 0a 67 72 | 65 61 74 6c 79 20 74 68 |() so.gr|eatly th|
|000006b0| 61 74 20 69 74 20 74 75 | 72 6e 73 20 6f 75 74 20 |at it tu|rns out |
|000006c0| 74 6f 20 62 65 20 62 65 | 74 74 65 72 20 74 6f 20 |to be be|tter to |
|000006d0| 64 65 66 69 6e 65 20 61 | 20 63 6f 6d 62 69 6e 65 |define a| combine|
|000006e0| 64 20 73 70 77 61 6e 28 | 29 0a 66 75 6e 63 74 69 |d spwan(|).functi|
|000006f0| 6f 6e 2e 20 20 54 68 69 | 73 20 77 6f 75 6c 64 20 |on. Thi|s would |
|00000700| 6d 61 6b 65 20 69 74 20 | 6c 65 73 73 20 6c 69 6b |make it |less lik|
|00000710| 65 6c 79 20 74 68 61 74 | 20 74 68 65 20 50 4f 53 |ely that| the POS|
|00000720| 49 58 20 73 74 61 6e 64 | 61 72 64 73 20 77 6f 75 |IX stand|ards wou|
|00000730| 6c 64 0a 63 6f 6e 74 61 | 69 6e 20 65 78 70 6c 69 |ld.conta|in expli|
|00000740| 63 69 74 20 6f 72 20 69 | 6d 70 6c 69 63 69 74 20 |cit or i|mplicit |
|00000750| 61 73 73 75 6d 70 74 69 | 6f 6e 73 20 61 62 6f 75 |assumpti|ons abou|
|00000760| 74 20 74 68 65 20 61 72 | 63 68 69 74 65 63 74 75 |t the ar|chitectu|
|00000770| 72 65 20 6f 66 20 74 68 | 65 0a 68 61 72 64 77 61 |re of th|e.hardwa|
|00000780| 72 65 20 6f 6e 20 77 68 | 69 63 68 20 61 20 63 6f |re on wh|ich a co|
|00000790| 6e 66 6f 72 6d 69 6e 67 | 20 69 6d 70 6c 65 6d 65 |nforming| impleme|
|000007a0| 6e 74 61 74 69 6f 6e 20 | 72 75 6e 73 2e 20 20 57 |ntation |runs. W|
|000007b0| 68 69 6c 65 20 74 68 69 | 73 20 6d 69 67 68 74 20 |hile thi|s might |
|000007c0| 62 65 0a 6e 69 63 65 20 | 66 6f 72 20 61 67 69 6e |be.nice |for agin|
|000007d0| 67 20 61 72 63 68 69 74 | 65 63 74 75 72 65 73 20 |g archit|ectures |
|000007e0| 73 75 63 68 20 61 73 20 | 74 68 61 74 20 6f 66 20 |such as |that of |
|000007f0| 28 73 61 79 29 20 74 68 | 65 20 55 6e 69 73 79 73 |(say) th|e Unisys|
|00000800| 20 31 31 30 30 0a 73 65 | 72 69 65 73 2c 20 6d 6f | 1100.se|ries, mo|
|00000810| 72 65 20 69 6d 70 6f 72 | 74 61 6e 74 6c 79 2c 20 |re impor|tantly, |
|00000820| 69 74 20 77 6f 75 6c 64 | 20 6e 6f 74 20 63 6f 6e |it would| not con|
|00000830| 73 74 72 61 69 6e 20 61 | 72 63 68 69 74 65 63 74 |strain a|rchitect|
|00000840| 75 72 61 6c 0a 61 64 76 | 61 6e 63 65 73 20 6f 66 |ural.adv|ances of|
|00000850| 20 74 68 65 20 66 75 74 | 75 72 65 20 6e 65 65 64 | the fut|ure need|
|00000860| 6c 65 73 73 6c 79 20 74 | 6f 20 63 6f 6e 66 6f 72 |lessly t|o confor|
|00000870| 6d 20 74 6f 20 74 68 65 | 20 6e 69 6e 65 74 65 65 |m to the| ninetee|
|00000880| 6e 0a 73 65 76 65 6e 74 | 69 65 73 27 20 69 64 65 |n.sevent|ies' ide|
|00000890| 61 73 20 6f 66 20 77 68 | 61 74 20 77 61 73 20 61 |as of wh|at was a|
|000008a0| 20 60 60 63 6c 65 61 6e | 20 6d 61 63 68 69 6e 65 | ``clean| machine|
|000008b0| 27 27 20 69 6e 20 6f 72 | 64 65 72 20 74 6f 20 62 |'' in or|der to b|
|000008c0| 65 20 61 62 6c 65 0a 65 | 66 66 69 63 69 65 6e 74 |e able.e|fficient|
|000008d0| 6c 79 20 74 6f 20 69 6d | 70 6c 65 6d 65 6e 74 20 |ly to im|plement |
|000008e0| 50 4f 53 49 58 20 69 6e | 74 65 72 66 61 63 65 73 |POSIX in|terfaces|
|000008f0| 2e 0a 0a 3e 20 4e 6f 77 | 2c 20 77 68 79 20 77 61 |...> Now|, why wa|
|00000900| 73 20 69 74 20 72 65 6d | 6f 76 65 64 3f 20 57 68 |s it rem|oved? Wh|
|00000910| 61 74 20 69 73 20 77 72 | 6f 6e 67 20 77 69 74 68 |at is wr|ong with|
|00000920| 20 69 74 3f 0a 0a 2d 2d | 20 73 65 65 20 61 6c 73 | it?..--| see als|
|00000930| 6f 20 63 6f 6d 70 2e 73 | 74 64 2e 75 6e 69 78 20 |o comp.s|td.unix |
|00000940| 56 6f 6c 75 6d 65 20 32 | 32 2c 20 4e 75 6d 62 65 |Volume 2|2, Numbe|
|00000950| 72 20 36 39 2e 0a 2d 2d | 20 0a 44 6f 6d 69 6e 69 |r 69..--| .Domini|
|00000960| 63 20 44 75 6e 6c 6f 70 | 0a 0a 56 6f 6c 75 6d 65 |c Dunlop|..Volume|
|00000970| 2d 4e 75 6d 62 65 72 3a | 20 56 6f 6c 75 6d 65 20 |-Number:| Volume |
|00000980| 32 32 2c 20 4e 75 6d 62 | 65 72 20 39 33 0a 0a |22, Numb|er 93.. |
+--------+-------------------------+-------------------------+--------+--------+