A sessão de perguntas e respostas de hoje nos é oferecida por cortesia do SuperUser, uma subdivisão do Stack Exchange, um agrupamento de sites de perguntas e respostas conduzido pela comunidade.
Foto cedida por Matt Dunlop (Flickr).
A questão
Leitor SuperUser cantsay quer saber porque os dados podem ser recuperados após a formatação:
If a quick format just marks bits as writable and a normal format writes zeroes to the entire disk, why do people bother with DBAN and why are multiple passes ever required?
Por que os dados podem ser recuperados após a formatação?
A resposta
O colaborador do SuperUser, Alex McKenzie, tem a resposta para nós:
It used to be possible by reading the residual magnetism left by the previous bits. This is not so much of an issue now that the tracks and bits that hard-drives write are so small. It is almost impossible to recover any meaningful data off of a zeroed drive with modern disks.
This next section is only true for Windows XP (as Psycogeek pointed out, Vista and later Windows systems do zero out the hard-drive if you do a full format).
That being said, your definitions of quick format and normal format are off. A normal format does not zero out the disk, that would take too long. The difference between the two is that a normal format looks for bad sectors on a drive while a quick format does not.
So it is best to use a tool like DBAN to do at least one pass if you want to make sure data is not recoverable. And if you are doing one pass, then why not do a few more just for fun?
Tem algo a acrescentar à explicação? Som desligado nos comentários. Quer ler mais respostas de outros usuários do Stack Exchange com experiência em tecnologia? Confira o tópico de discussão completo aqui.
