{"id":85,"date":"2004-03-07T23:17:50","date_gmt":"2004-03-07T23:17:50","guid":{"rendered":"https:\/\/143-42-55-146.ip.linodeusercontent.com\/?p=85"},"modified":"2004-03-07T23:17:50","modified_gmt":"2004-03-07T23:17:50","slug":"zamerovani-ronji-ii-dil","status":"publish","type":"post","link":"https:\/\/nax.cz\/?p=85","title":{"rendered":"ZAM\u00c4\u009a\u0139\u0098OV\u0102\u0081N\u0102\u008d RONJI – II. D\u0102\u008dL"},"content":{"rendered":"

Dnes jsme cht\u00c4\u009bli dokon\u00c4\u008dit co jsme v\u00c4\u008dera zapo\u00c4\u008dali s FoTomem. Je\u0139\u0104t\u00c4\u009b jsem si vzpomn\u00c4\u009bl, \u0139\u017ee v\u00c4\u008dera jsem si samoz\u0139\u0099ejm\u00c4\u009b od n\u00c4\u009bj neodnesl ten krasn\u0102\u02dd tenk\u0102\u02dd plech ide\u0102\u0104ln\u0102\u00ad to materi\u0102\u0104l na krabi\u00c4\u008dky do kter\u0102\u02ddch se bude prasit to vrab\u00c4\u008d\u0102\u00ad hn\u0102\u00adzdo a tak jsem tentokr\u0102\u0104t p\u0139\u0099i\u0139\u0104el o n\u00c4\u009bco d\u0139\u0099\u0102\u00adve abych ty krabi\u00c4\u008dky vyst\u0139\u0099\u0102\u00adhal z toho plechu p\u0139\u0099\u0102\u00admo u n\u00c4\u009bj. Nakonec jsme stihly jen RX a TX krabi\u00c4\u008dku a AUI modul jsme nechali na jindy. Ka\u0139\u017edop\u0102\u0104dn\u00c4\u009b te\u00c4\u008f je\u0139\u0104t\u00c4\u009b vyvrtat d\u0102\u00adry a m\u0139\u017b\u0139\u017eu za\u00c4\u008d\u0102\u00adt letovat.<\/p>\n

Jen mysl\u0102\u00adm, \u0139\u017ee poslechnu radu zku\u0139\u0104en\u00c4\u009bj\u0139\u0104\u0102\u00adho a je\u0139\u0104t\u00c4\u009b si po\u0139\u0099\u0102\u00add\u0102\u00adm n\u00c4\u009bjakou mikrop\u0102\u0104jku. Pr\u0102\u02dd by byla dobr\u0102\u0104 n\u00c4\u009bjak\u0102\u0104 v\u0102\u02ddkonn\u00c4\u009bj\u0139\u0104\u0102\u00ad, proto\u0139\u017ee u nich se d\u0102\u0104 v\u0102\u02ddkon v\u0139\u017edy sn\u0102\u00ad\u0139\u017eit. N\u00c4\u009bkdy p\u0139\u0099\u0102\u00ad\u0139\u0104t\u0102\u00ad t\u0102\u02ddden si ji koup\u0102\u00adm ve V\u0102\u0104clavsk\u0102\u0160 pas\u0102\u0104\u0139\u017ei.<\/p>\n

Je\u0139\u0104t\u00c4\u009b ne\u0139\u017e se \u0102\u015fpln\u00c4\u009b setm\u00c4\u009blo, tak jsme obr\u0102\u0104tili \u0139\u0104rouby tak, aby hlavou koukaly na n\u0102\u0104s. Tak\u0102\u0160 chci poopravit jeden v\u00c4\u008derej\u0139\u0104\u0102\u00ad \u0102\u015fdaj – ty dola\u00c4\u008fovac\u0102\u00ad \u0139\u0104rouby tam nejsou 2 na ka\u0139\u017ed\u0102\u02dd tubus, ale 4 – pro ka\u0139\u017ed\u0102\u02dd sm\u00c4\u009br jeden. Idea je hezk\u0102\u0104 – dotahuje\u0139\u0104 horn\u0102\u00ad a tubus se st\u0102\u0104\u00c4\u008d\u0102\u00ad nahoru – ale v praxi hodn\u00c4\u009b z\u0102\u0104le\u0139\u017e\u0102\u00ad na tom, jak moc jsou dot\u0102\u0104hl\u0102\u0160 zrovna ostatn\u0102\u00ad \u0139\u0104rouby.<\/p>\n

Na tohle t\u0102\u0160ma prob\u00c4\u009bhla diskuse s Ond\u0139\u0099ejem po vys\u0102\u00adla\u00c4\u008dce a prej v prvn\u0102\u00adch verz\u0102\u00adch dr\u0139\u017e\u0102\u0104ku byly ty \u0139\u0104rouby v\u0139\u017edy 2 a 2 nad sebou. Tedy kdy\u0139\u017e jste cht\u00c4\u009bli doprava,tak jste museli ut\u0102\u0104hnout stejn\u00c4\u009b oba \u0139\u0104rouby napravo. Pr\u0102\u02dd to nem\u00c4\u009blo tu vlastnost, \u0139\u017ee z\u0102\u0104le\u0139\u017eelo na dot\u0102\u0104hnut\u0102\u00ad ostatn\u0102\u00adch dvou \u0139\u0104roub\u0139\u017b, ale blb\u00c4\u009b se to regulovalo stejn\u00c4\u009b.<\/p>\n

Tentokr\u0102\u0104t jsme si tak\u0102\u0160 p\u0139\u0099inesly pon\u00c4\u009bkud lep\u0139\u0104\u0102\u00ad \u0139\u0104tafle ne\u0139\u017e v\u00c4\u008dera a hlavn\u00c4\u009b lep\u0139\u0104\u0102\u00ad „dotahov\u0102\u0104tko“ (takov\u0102\u0160 kter\u0102\u0160 se jen nasad\u0102\u00ad a p\u0102\u0104\u00c4\u008dkou se d\u00c4\u009bl\u0102\u0104 nahoru a dolu a nemus\u0102\u00ad se tedy sundavat z toho \u0139\u0104roubu). Tak\u0102\u0160 jsme u\u0139\u017e naprosto p\u0139\u0099esn\u00c4\u009b v\u00c4\u009bd\u00c4\u009bli kde ta ond\u0139\u0099ejova ronja je. P\u0139\u0099esn\u00c4\u009b jsme v\u00c4\u009bd\u00c4\u009bli, \u0139\u017ee kdy\u0139\u017e nad t\u0102\u0104mhlentou v\u0102\u02ddtahovou \u0139\u0104achtou p\u0139\u017bjdeme nahoru tak naraz\u0102\u00adme na 2 sv\u00c4\u009btla a u toho lev\u0102\u0160ho to je. Skoro jako kdy\u0139\u017e zku\u0139\u0104en\u0102\u02dd astronom hled\u0102\u0104 souhv\u00c4\u009bzd\u0102\u00ad b\u0102\u02ddka.<\/p>\n

V podstat\u00c4\u009b n\u0102\u0104m na nastaven\u0102\u00ad obou tubus\u0139\u017b i s relativn\u00c4\u009b dobr\u0102\u02ddm dot\u0102\u0104hnut\u0102\u00adm (Ondra \u0139\u0099\u0102\u00adkal, \u0139\u017ee pr\u0102\u02dd by na v\u0139\u0104ech \u0139\u0104roubech m\u00c4\u009bla b\u0102\u02ddt guma st\u0102\u0104hnut\u0102\u0104 alespo\u0139\u0088 na polovinu) n\u0102\u0104m to trvalo cca 3 hodiny.<\/p>\n

Nejprve jsme nam\u00c4\u009b\u0139\u0099ili lev\u0102\u02dd tubus, pak jsme p\u0139\u0099endali vys\u0102\u00adla\u00c4\u008d do prav\u0102\u0160ho a znovu jsme hledali odrazku. Nakonec se povedlo i to a zb\u0102\u02ddvalo trochu si pohr\u0102\u0104t s ohniskem, co\u0139\u017e prob\u0102\u00adhalo tak, \u0139\u017ee jsme pomalu posouvali vys\u0102\u00adla\u00c4\u008dem v tubusu a Ond\u0139\u0099ej n\u0102\u0104m do vys\u0102\u00adla\u00c4\u008dky p\u0139\u0099ed\u00c4\u008d\u0102\u00adtal hodnoty, kter\u0102\u0160 mu ukazuje jeho voltmetr. Pak jsme to ud\u00c4\u009blali opa\u00c4\u008dn\u00c4\u009b a bylo. Konkr\u0102\u0160tn\u00c4\u009b jsme se my dostali na hodnotu 320-350mV a Ond\u0139\u0099ej to se\u0139\u0104teloval u sebe na n\u00c4\u009bjak\u0102\u02ddch 290mV.<\/p>\n

Vzhledem k tomu, \u0139\u017ee Ond\u0139\u0099ej sice m\u0102\u0104 u\u0139\u017e p\u0139\u0099ipraven\u0102\u02dd po\u00c4\u008d\u0102\u00adta\u00c4\u008d, ale nem\u0102\u0104 v n\u00c4\u009bm hard disk, tak n\u0102\u0104m propojil v AUI p\u0139\u0099ij\u0102\u00adma\u00c4\u008d s vys\u0102\u00adla\u00c4\u008dem, tak\u0139\u017ee vznikl takov\u0102\u02dd velk\u0102\u02dd loopback. Dopoledne jsem zrovna na\u0139\u0104el n\u0102\u0104vod na loopback testov\u0102\u0104n\u0102\u00ad ronji<\/a>. Postupoval jsem podle toho n\u0102\u0104vodu n\u0102\u0104sledovn\u00c4\u009b:<\/p>\n

modprobe 3c509 options 1 full_duplex 1<\/strong>
\nethtool -s eth1 duplex full speed 10 port aui<\/strong>
\nifconfig eth1 192.168.2.1 netmask 255.255.255.0<\/strong>
\narp -i eth1 -s 192.168.2.2 00:A0:24:71:B3:C5<\/strong><\/p>\n

Pak jsem je\u0139\u0104t\u00c4\u009b musel vypnout firewall, ale dost mne vyvedlo z m\u0102\u00adry, \u0139\u017ee jsem na tcpdumpu nepoznal, \u0139\u017ee by se d\u00c4\u009blo n\u00c4\u009bco jako odpov\u00c4\u009b\u00c4\u008f.<\/p>\n

Zat\u0102\u00adm co jsem \u0139\u0104el dom\u0139\u017b se mi to ale rozle\u0139\u017eelo v hlav\u00c4\u009b a uv\u00c4\u009bdomil jsem si, \u0139\u017ee p\u0139\u0099eci nen\u0102\u00ad od koho tu odpov\u00c4\u009b\u00c4\u008f dost\u0102\u0104vat. Jedin\u0102\u0160 podle \u00c4\u008deho poznat, \u0139\u017ee ten spoj chod\u0102\u00ad je, \u0139\u017ee se prost\u00c4\u009b na tcpdump v\u0102\u02ddpisu m\u0102\u00adsto jednoho echo request objev\u0102\u02dd ty po\u0139\u017eadavky dva (jeden odeslan\u0102\u02dd a druh\u0102\u02dd p\u0139\u0099ijat\u0102\u02dd). Abych to vid\u00c4\u009bl, tak jsem specifikoval, \u0139\u017ee chci ping pos\u0102\u00adlat v intervalu 5s:<\/p>\n

ping -i 5 192.168.2.2<\/strong><\/p>\n

No a v\u0102\u02ddpis z tcpdumpu pak vypad\u0102\u0104 n\u0102\u0104sledovn\u00c4\u009b:<\/p>\n

# tcpdump -i eth1<\/strong>
\ntcpdump: listening on eth1
\n23:35:11.535714 192.168.2.1 > 192.168.2.2: icmp: echo request (DF)
\n23:35:11.536030 192.168.2.1 > 192.168.2.2: icmp: echo request (DF)
\n23:35:16.535711 192.168.2.1 > 192.168.2.2: icmp: echo request (DF)
\n23:35:16.536034 192.168.2.1 > 192.168.2.2: icmp: echo request (DF)
\n23:35:21.535717 192.168.2.1 > 192.168.2.2: icmp: echo request (DF)
\n23:35:21.536051 192.168.2.1 > 192.168.2.2: icmp: echo request (DF)<\/p>\n

6 packets received by filter
\n0 packets dropped by kernel<\/p>\n

Na prvn\u0102\u00ad pohled tedy \u0139\u017e\u0102\u0104dn\u0102\u02dd zvl\u0102\u0104\u0139\u0104tn\u0102\u00ad rozd\u0102\u00adl, ale kdy\u0139\u017e se pod\u0102\u00adv\u0102\u0104te na \u00c4\u008dasy, tak je v\u0139\u0104e jasn\u0102\u0160. Prost\u00c4\u009b to chod\u0102\u00ad. Te\u00c4\u008f u\u0139\u017e mne jen \u00c4\u008dek\u0102\u0104 boj s v\u00c4\u009btrn\u0102\u02ddmi ml\u0102\u02ddny abych pro Ond\u0139\u0099eje vybojoval n\u00c4\u009bjak\u0102\u0160 IP a pak to jen hezky donastavit a bude prvn\u0102\u00ad linka na ronje v Mod\u0139\u0099anech v provozu.<\/p>\n

No a nav\u0102\u00adc m\u0102\u0104m t\u0102\u0160ma pro svoj\u0102\u00ad semestr\u0102\u0104lku z p\u0139\u0099edm\u00c4\u009btu C++. Kdy\u0139\u017e u\u0139\u017e tady tu linku m\u0102\u0104me, tak by se p\u0139\u0099eci hodil n\u00c4\u009bjak\u0102\u02dd progr\u0102\u0104mek, kter\u0102\u02dd by monitoroval tu linku, dok\u0102\u0104zal statisticky vyhodnotit v\u0102\u02ddpadky a hlavn\u00c4\u009b (a to mysl\u0102\u00adm v \u0139\u017e\u0102\u0104dn\u0102\u0160m sou\u00c4\u008dasn\u0102\u0160m softwaru nenajdu) by dok\u0102\u0104zal ty v\u0102\u02ddsledky spojit s po\u00c4\u008das\u0102\u00adm, jak\u0102\u0160 zrovna v dob\u00c4\u009b v\u0102\u02ddpadku bylo.<\/p>\n","protected":false},"excerpt":{"rendered":"

Dnes jsme cht\u00c4\u009bli dokon\u00c4\u008dit co jsme v\u00c4\u008dera zapo\u00c4\u008dali s FoTomem. Je\u0139\u0104t\u00c4\u009b jsem si vzpomn\u00c4\u009bl, \u0139\u017ee v\u00c4\u008dera jsem si samoz\u0139\u0099ejm\u00c4\u009b od n\u00c4\u009bj neodnesl ten krasn\u0102\u02dd tenk\u0102\u02dd plech ide\u0102\u0104ln\u0102\u00ad to materi\u0102\u0104l na krabi\u00c4\u008dky do kter\u0102\u02ddch se bude prasit to vrab\u00c4\u008d\u0102\u00ad hn\u0102\u00adzdo a tak jsem tentokr\u0102\u0104t p\u0139\u0099i\u0139\u0104el o n\u00c4\u009bco d\u0139\u0099\u0102\u00adve abych ty krabi\u00c4\u008dky vyst\u0139\u0099\u0102\u00adhal z toho plechu p\u0139\u0099\u0102\u00admo […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[],"class_list":["post-85","post","type-post","status-publish","format-standard","hentry","category-hw"],"_links":{"self":[{"href":"https:\/\/nax.cz\/index.php?rest_route=\/wp\/v2\/posts\/85","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nax.cz\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/nax.cz\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/nax.cz\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/nax.cz\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=85"}],"version-history":[{"count":0,"href":"https:\/\/nax.cz\/index.php?rest_route=\/wp\/v2\/posts\/85\/revisions"}],"wp:attachment":[{"href":"https:\/\/nax.cz\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=85"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nax.cz\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=85"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nax.cz\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=85"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}