To pragmatiko shmeio kamphs toy sxedioy htan otan o Harry Hochheiser moy esteile to prosxedio toy kwdika toy gia prow8hsh taxydromeio sthn 8ura SMTP toy ypologisth poy 8a filojenouse ton client. Sxedon amesws katalaba oti mia swsth ylopoihsh aytou toy xarakthristikou 8a ka8istouse ka8e allh me8odo paradoshs taxydromeioy aparxaiwmenh.
Gia polles ebdomades emba8yna sto fetchmail olo kai pio polu kai, taytoxrona, eniw8a oti to interface antexe sthn xrhsh alla htan aperipoihto, akomco kai me para polla mikra options edw ki ekei. H epilogh dioxeteyshs toy taxydromeioy poy eixe hdh paralhf8ei sto arxeio mailbox h sthn stantar ejodo me enoxlouse, alla den katalabaina giati.
Ayto poy eida, otan skefthka thn prow8hsh mhnymatwn mesw SMTP, htan oti o popclient prospa8ouse na kanei para polla pragmata. Eixe sxediastei na einai ena programma metaforas taxydromeioy (MTA) ki ena programma topikhs dianomhs taxydromeioy (MDA). Me thn prow8hsh SMTP 8a mporouse na apallagei ap' thn leitoyrgia MDA kai na einai ena aplo MTA, metaferontas ta mhnumata se alla programmata, gia topikh paralabh, opws akribws to sendmail.
Giati na periplekw ta pragmata ry8mizontas ena programma dianomhs taxydromeioy h na efarmozw thn leitoyrgia lock-and-append s' ena mailbox, th stigmh poy h 8ura 25 eggyhmena yparxei se ka8e platforma me yposthrijh TCP/IP ap' thn arxh; Idiaitera otan ayto shmainei oti, h allhlografia poy paralambanetai moiazei sigoyra me ena kanoniko taxydromeio SMTP poy energopoieitai ap' ton apostolea, pragma to opoio einai ayto poy zhtame.
Ta ma8hmata edw einai polla. Prwton, ayth h idea prow8hshs mesw SMTP htan to shmantikotero poy kerdisa ap' thn syneidhth prospa8eia moy na ejomoiwsw tis me8odoys toy Linus. Enas xrhsths moy edwse ayth thn polu kalh idea-ayto poy eprepe na kanw htan na katalabw tis epiplokes.
11. To pio spoydaio meta apo to na exeis kales idees, einai na anagnwrizeis tis kales idees twn xrhstwn soy. Merikes fores to teleytaio einai kalutero.
Suntoma 8a katalabeis oti, an eisai entelws eilikrinhs gia to posa xrwstas stoys alloys kai kaneis aytokritikh, o kosmos 8a soy symperiferetai san na einai dikh soy h epinohsh kai 8a einai metriofrones gia thn emfyth eyfyia soy. Oloi mporoume na doume poso kala ayto leitourghse gia ton Linus!
(Otan edwsa ayto to keimeno se ena synedrio me 8ema thn Perl ton Augoysto toy 1997, O Larry Wall ka8ontan sthn prwth grammh. Epeidh egw ka8omoyn sthn teleytaia seira moy fwnaje, me styl 8rhskeytikhs anazwpurwshs [religious-revival style], "Pesta, pesta, aderfe!". Olo to akroathrio gelase , epeidh hjeran oti oi apoceis moy eixan doylecei kai gia ton dhmioyrgo ths Perl.)
Meta apo liges ebdomades doyleuontas sto sxedio me to idio pneuma arxisa na pairnw paromoioys epainoys oxi mono apo toys xrhstes moy, alla ki apo alloys an8rwpoys poy ema8an ol' ayta. Fulaja san 8hsayro kapoia apo ayta ta Email, merikes fores ta janakoitaw otan arxizw na anarwtiemai an h zwmou ajizei ton kopo :-)
Omws, edw yparxoyn alla duo 8emeliwdh mh politika ma8hmata, poy efarmozontai se ka8e eidos sxediasmou.
12. Syxna, oi pio faneres kai kainotomikes luseis emfanizontai otan blepeis oti h antilhch poy exeis gia to problhma einai la8os.
Prospa8ousa na lusw la8os problhma me to na synexizw na anaptussw ton popclient san ena syndyasmo MTA/MDA, me ola ta eidh me8odwn topikhs dianomhs taxydromeioy. Eprepe na skeftw pali to fetchmail ap' thn arxh, san ena ka8aro MTA, san meros toy kanonikou SMTP Internet taxydromeioy.
Otan ftaneis se adiejodo-otan nomizeis oti dyskoleuesai na skefteis to epomeno patch-syxna einai kairos na skefteis oxi an exeis thn swsth apanthsh, alla an rwtas thn swsth erwthsh. Isws prepei na to problhma na diey8eth8ei ek neoy.
Ayto ki ekana. 3eka8ara, ayto poy eprepe na kanw htan (1) na eisagw yposthrijh prow8hshs SMTP ston geniko driver, (2) na thn ry8misw ws ej orismou leitoyrgia kai, (3) na apallagw apo oles tis alles leitoyrgies dianomhs, idiaitera thn apo8hkeysh twn mhnymatwn se arxeio kai thn metabibash sthn stantar ejodo.
Ka8ysterhsa gia ligo sto stadio (3), foboumenos na anastatwsw toys xrhstes poy xrhsimopoiousan gia megalo diasthma popclient kai hsan ejarthmenoi ap' toys enallaktikous mhxanismous paralabhs. 8ewrhtika, 8a mporousan na metabainoyn sta arxeia .forward h sta non-sendmail isodunama toys, kai na exoyn to idio apotelesma. Sthn prajh, h metabash ayth fainotan akatastath.
Otan, omws, ta katafera to kerdos apodeixthke megalo. Ta dyskolotera merh toy driver ejafanisthkan. H ru8mish egine rizika aplousterh-terma h anazhthsh gia to MDA toy systhmatos kai to mailbox toy xrhsth, telos stis anhsyxies gia to ean to leitoyrgiko programma yposthrizei kleidwma twn arxeiwn [file locking].
Epishs, o monos tropos na xaseis mhnumata ejafanisthke. An exeis orisei h paralabh twn mhnymatwn na proskollh8ei s' ena arxeio ki o diskos einai gematos, ta mhnumata soy xanontan. Ayto den symbainei me thn prow8hsh mesw SMTP, epeidh o SMTP listener den 8a epistrecei OK mexris otoy ta mhnumata paralhf8oun h, toylaxiston, mpoyn sthn seira gia paradosh kapoia allh stigmh.
Akomh, beltiw8hke h apodosh (an kai den 8a to prosejei kaneis me mia aplh xrhsh toy programmatos). Ena allo oxi ashmanto ofelos ayths ths allaghs htan oti to egxeiridio xrhshs egine aploustero.
Argotera, eprepe na ry8misw thn paralabh twn mhnymatwn mesw enos topikou MDA ka8orismeno apo ton xrhsth, wste na epitrecw ton elegxo kapoiwn skoteinwn katastasewn sxetika me thn dynamic SLIP. Brhka, omws, enan pio aplo tropo gia na to kanw.
H8iko didagma; Mhn distazeis na petajeis parwxhmena xarakthristika otan mporeis na to kaneis xwris apwleies sthn apotelesmatikothta. O Antoyan Saint-Ejperu (poy htan pilotos kai sxediasths aeroskafwn, otan den egrafe klasika biblia gia paidia) exei pei:
13. H teleiothta (ston sxediasmo) einai dynath oxi otan den yparxei kati gia na pros8eseis, alla mallon otan den yparxei kati gia na afaireseis.
Otan o kwdikas soy ginetai kaluteros kai aplousteros, tote jereis oti einai swstos. Kai sthn poreia to fetchmail apekthse dikh toy taytothta, diaforetikh ap' ton progono toy popclient.
Htan wra gia thn allagh toy onomatos. To neo programma emoiaze perissotero m' ena diplo sendmail poy die8ete o palios poclient. Kai ta duo einai MTA, alla ekei poy to sendmail sprwxnei thn paradosh toy taxydromeioy, o neos popclient thn elkuei. Etsi, meta apo duo mhnes leitoyrgias xwris empodia, ton onomasa fetchmail.