Današnja pitanja i odgovori nam se javljaju zahvaljujući SuperUseru - podjele Stack Exchange-a, zajedničkom pogonu Q & A web stranica.
Pitanje
SuperUser čitač FrozenKing želi znati kako njegovo računalo zna kada se srušio ili na neki drugi način imao neispravno zatvaranje. Piše:
Actually, this question struck me because of power cuts in my house. When there is a power cut, there is a sudden loss of power from the computer.
How does the computer know that the shutdown was not properly done?
To je zanimljivo pitanje; jasno suvremeni operacijski sustavi dobro su svjesni da nešto nije pošlo po zlu, ali kojim mehanizmom su oni svjesni?
Odgovori
SuperUser suradnik David Schwartz nudi opći odgovor i uvid u različite operacijske sustave:
For non-Windows based PCs, the detection is usually done on a per-filesystem basis. When a filesystem is mounted in read/write mode, an entry is written to the filesystem marking it dirty. When the filesystem is unmounted, an entry is written marking it clean. On startup, the operating system checks if its core filesystems are marked dirty, and if so it knows there wasn’t a clean shutdown - at least of those filesystems.
Još jedan suradnik, ChrisF odgovara više za operacijski sustav Windows:
When powered off as normal, the bit is switched off. However, in case of power outage or improper (forced) shutdown, the bit will still be on the next time the PC is started.
This means that Windows can suggest remedial action – such as booting into Safe Mode.
In addition a Windows based PC will write an entry into event log detailing when and why (if known) it was shut down. It also writes an event when the PC starts up.
Imate li nešto za objašnjenje? Zvuči u komentarima. Želite li pročitati više odgovora od drugih tehnoloških korisnika Stack Exchangea? Pogledajte ovdje cijelu raspravu.