[OS] Discussion for exam questions ...

[Petr Tůma]

Hi,

in a private mail thread, I've been discussing some exam questions, and I thought the links might come in handy to other people (numbers refer to the test from Jan 23, sorry for the rest being in Czech, the links work though :-):

- k prikladu cislo 1 doporucuji podivat se napriklad na https://geidav.wordpress.com/2016/03/23/test-and-set-spinlocks, kdyz reseni zkusite upravit z test-and-set na read-and-add, mohu jej vice okomentovat (klidne poslete mailem), jina mozna implementace je treba na wikipedii na https://en.wikipedia.org/wiki/fetch-and-add (rikaji tomu mutual exclusion lock)

- k prikladu cislo 2 jako prvni cast uplne staci co jste meli na cviceni na procesoru MIPS, tedy v manualu https://d3s.mff.cuni.cz/teaching/operating_systems/download/R4000_Users_Manual_2Ed.pdf nejaka zjednodusena podoba tabulky Figure 4-8 (k zakladni funkci jsou potreba vlastne jen pole VPN a PFN, rada spravnych odpovedi uvadela jeste pole ASID, bit G, pripadne se obecne zminovala o tom, ze mohou existovat i dalsi bity kolem pristupovych prav)

- u prikladu cislo 4 potrebuji lepe vedet, co vam neni jasne - otazka mirila na fragmentaci heapu, viz napriklad https://stackoverflow.com/questions/3770457/what-is-memory-fragmentation, https://cpp4arduino.com/2018/11/06/what-is-heap-fragmentation.html, nebo treba https://www.design-reuse.com/articles/25090/dynamic-memory-allocation-fragmentation-c.html

- u prikladu cislo 6 podobne jako vyse - jedna se o rezii pri ukladani souboru, trochu navodny link muze byt asi treba https://askubuntu.com/questions/234913/why-is-disk-usage-greater-than-the-size-of-all-files-on-it

Petr