{"id":104,"date":"2004-05-29T13:37:32","date_gmt":"2004-05-29T13:37:32","guid":{"rendered":"https:\/\/143-42-55-146.ip.linodeusercontent.com\/?p=104"},"modified":"2004-05-29T13:37:32","modified_gmt":"2004-05-29T13:37:32","slug":"odkazy-tykajici-se-operacnich-systemu","status":"publish","type":"post","link":"https:\/\/nax.cz\/?p=104","title":{"rendered":"ODKAZY T\u0102\u009dKAJ\u0102\u008dC\u0102\u008d SE OPERA\u00c4\u008cN\u0102\u008dCH SYST\u0102\u0089M\u0139\u017d"},"content":{"rendered":"<p>Jak jsem psal u\u0139\u017e v\u00c4\u008dera te\u00c4\u008f se drt\u0102\u00adm na zkou\u0139\u0104ku z p\u0139\u0099edm\u00c4\u009btu OSY. Minul\u0102\u02dd t\u0102\u02ddden jsem si v\u0139\u0104iml, \u0139\u017ee mezi <a href=\"http:\/\/unix.felk.cvut.cz\/osy\/cz_zdroje.html\">literaturou a slidy<\/a> je i odkaz na <a href=\"http:\/\/williamstallings.com\/OS4e.html\">dal\u0139\u0104\u0102\u00ad u\u0139\u017eite\u00c4\u008dn\u0102\u0160 zdroje<\/a>. Proch\u0102\u0104zel jsem si to a ur\u00c4\u008dit\u00c4\u009b se k tomu vr\u0102\u0104t\u0102\u00adm je\u0139\u0104t\u00c4\u009b a\u0139\u017e ud\u00c4\u009bl\u0102\u0104m zkou\u0139\u0104ky. Jsou tam jednak n\u00c4\u009bjak\u0102\u0160 usnetov\u0102\u0160 konference a pak taky t\u0139\u0099eba <a href=\"ftp:\/\/ftp.prenhall.com\/pub\/esm\/computer_science.s-041\/stallings\/Slides\/OS4e-PDF-Slides\/\">dal\u0139\u0104\u0102\u00ad zaj\u0102\u00admav\u0102\u0160 slidy<\/a> nebo <a href=\"http:\/\/www.osdata.com\/\">Operating System Technical Comparison<\/a> co\u0139\u017e je skute\u00c4\u008dn\u00c4\u009b vy\u00c4\u008derp\u0102\u0104vaj\u0102\u00adc\u0102\u00ad materi\u0102\u0104l o v\u0139\u0104ech mo\u0139\u017en\u0102\u02ddch i nemo\u0139\u017en\u0102\u02ddch OS.<\/p>\n<p>P\u0139\u0099i proch\u0102\u0104zen\u0102\u00ad p\u0139\u0099edn\u0102\u0104\u0139\u0104ky <a href=\"http:\/\/unix.felk.cvut.cz\/osy\/slides\/04-Scheduling.pdf\">o pl\u0102\u0104nov\u0102\u0104n\u0102\u00ad proces\u0139\u017b<\/a> jsem m\u00c4\u009bl trochu probl\u0102\u0160m pochopit p\u0139\u0099edposledn\u0102\u00ad slidem kde je vysv\u00c4\u009btlov\u0102\u0104n algoritmus shortest process next pro rozhodnut\u0102\u00ad, kter\u0102\u02dd proces napl\u0102\u0104novat jako dal\u0139\u0104\u0102\u00ad. Tento algoritmus vych\u0102\u0104z\u0102\u00ad z nonpreemptivn\u0102\u00adho (tedy takov\u0102\u0160ho kdy v\u0139\u017edy ka\u0139\u017ed\u0102\u02dd proces b\u00c4\u009b\u0139\u017e\u0102\u00ad dokud neskon\u00c4\u008d\u0102\u00ad nebo se s\u0102\u0104m nezablokuje) shortest job first, kter\u0102\u02dd m\u0102\u0104 oproti first come &#8211; first served v\u0102\u02ddhodn\u00c4\u009bj\u0139\u0104\u0102\u00ad pr\u0139\u017bm\u00c4\u009brn\u0102\u02dd turnaround (tedy \u00c4\u008das mezi po\u0139\u017eadavkem na v\u0102\u02ddpo\u00c4\u008det prosesu a jeho dokon\u00c4\u008den\u0102\u00adm v\u00c4\u008detn\u00c4\u009b \u00c4\u008dasu kdy \u00c4\u008dek\u0102\u0104 a\u0139\u017e se zpracuj\u0102\u00ad jin\u0102\u0160 procesy).<\/p>\n<p>Ten shortest process next je oproti tomu preemptivn\u0102\u00ad, tedy takov\u0102\u02dd kter\u0102\u02dd po ur\u00c4\u008dit\u0102\u0160m \u00c4\u008dasov\u0102\u0160m quantu p\u0139\u0099epne na jin\u0102\u02dd proces s\u0102\u0104m a je tedy pot\u0139\u0099eba u interaktivn\u0102\u00adch syst\u0102\u0160m\u0139\u017b. Na tom slidu je uveden\u0102\u02dd vzorec:<\/p>\n<p><strong>k T0 + (1 &#8211; k) T1<\/strong><\/p>\n<p>kde k je konstanta mezi 0 a 1. Moc jsem to nech\u0102\u0104pal jak tomu m\u0102\u0104m rozum\u00c4\u009bt. Trochu jsem zkou\u0139\u0104el googlit a zjistil jsem, \u0139\u017ee materi\u0102\u0104l\u0139\u017b zab\u0102\u02ddvaj\u0102\u00adc\u0102\u00ad se teoriemi OS je opravdu hodn\u00c4\u009b. Nam\u0102\u0104tkou <a href=\"http:\/\/www.cim.mcgill.ca\/~franco\/OpSys-304-427\/lecture-notes\/node1.html\">tady<\/a> nebo <a href=\"http:\/\/www.cs.nott.ac.uk\/~gxk\/courses\/g53ops\/index.html\">tady<\/a>. Dokonce jsem na\u0139\u0104el jeden docela zaj\u0102\u00admav\u0102\u02dd <a href=\"http:\/\/www.cim.mcgill.ca\/~franco\/OpSys-304-427\/lecture-notes\/node1.html\">test zab\u0102\u02ddvaj\u0102\u00adc\u0102\u00ad se shedullingem<\/a>. Nakonec jsem ten algoritmus pochopil z <a href=\"http:\/\/www.cs.nott.ac.uk\/~gxk\/courses\/g53ops\/Scheduling\/sched05-sjf.html\">tohohle slidu<\/a>.<\/p>\n<p>Je to tak, \u0139\u017ee T0 je v\u0139\u017edy doba v\u0139\u0104ech p\u0139\u0099edchoz\u0102\u00adch b\u00c4\u009bh\u0139\u017b (krom\u00c4\u009b toho posledn\u0102\u00adho) a T1 je \u00c4\u008das b\u00c4\u009bhu v posledn\u0102\u00adm \u00c4\u008dasov\u0102\u0160m quantu. Konstanta k pak ud\u0102\u0104v\u0102\u0104 jestli v\u0102\u00adce z\u0102\u0104le\u0139\u017e\u0102\u00ad na pr\u0139\u017bm\u00c4\u009brn\u0102\u0160 d\u0102\u0160lce v\u0139\u0104ech dosavadn\u0102\u00adch quant a nebo n\u0102\u0104m z\u0102\u0104le\u0139\u017e\u0102\u00ad jen na velikosti toho posledn\u0102\u00adho.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Jak jsem psal u\u0139\u017e v\u00c4\u008dera te\u00c4\u008f se drt\u0102\u00adm na zkou\u0139\u0104ku z p\u0139\u0099edm\u00c4\u009btu OSY. Minul\u0102\u02dd t\u0102\u02ddden jsem si v\u0139\u0104iml, \u0139\u017ee mezi literaturou a slidy je i odkaz na dal\u0139\u0104\u0102\u00ad u\u0139\u017eite\u00c4\u008dn\u0102\u0160 zdroje. Proch\u0102\u0104zel jsem si to a ur\u00c4\u008dit\u00c4\u009b se k tomu vr\u0102\u0104t\u0102\u00adm je\u0139\u0104t\u00c4\u009b a\u0139\u017e ud\u00c4\u009bl\u0102\u0104m zkou\u0139\u0104ky. Jsou tam jednak n\u00c4\u009bjak\u0102\u0160 usnetov\u0102\u0160 konference a pak taky t\u0139\u0099eba dal\u0139\u0104\u0102\u00ad [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[35,13],"tags":[],"class_list":["post-104","post","type-post","status-publish","format-standard","hentry","category-linux","category-skola"],"_links":{"self":[{"href":"https:\/\/nax.cz\/index.php?rest_route=\/wp\/v2\/posts\/104","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=104"}],"version-history":[{"count":0,"href":"https:\/\/nax.cz\/index.php?rest_route=\/wp\/v2\/posts\/104\/revisions"}],"wp:attachment":[{"href":"https:\/\/nax.cz\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=104"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nax.cz\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=104"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nax.cz\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=104"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}