September 2025
Intermediate to advanced
660 pages
13h 38m
Portuguese (Portugal, Brazil)
Content preview from Introdução ao Python, 3rd Edition
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Capítulo 21. Dados no tempo: simultaneidade
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Tudo o que temos que decidir é o que fazer com o tempo que nos é dado.
J. R. R. Tolkien
Este capítulo e os próximos dois são mais longos e um pouco mais desafiadores do que os anteriores: dados no tempo (acesso sequencial e simultâneo em um único computador), depois dados no espaço (rede) e, finalmente, dados em uma caixa (armazenamento e recuperação com arquivos e bancos de dados especiais).
Programas e processos
Quando você executa um programa individual, o sistema operacional cria um único processo, que utiliza recursos do sistema (CPU, memória, espaço em disco) e estruturas de dados no kerneldo sistema operacional (conexões de arquivo e de rede, estatísticas de uso, etc.). Um processo é isolado de outros processos; ele não pode ver o que os outros processos estão fazendo nem interferir neles.
O sistema operacional controla todos os processos em execução, dando a cada um deles um pouco de tempo para execução e, em seguida, alternando para outro, com o duplo objetivo de distribuir o trabalho de forma justa e ser responsivo ao usuário. Você pode ver o estado dos seus processos com interfaces gráficas, como o Monitor de Atividades do Mac (macOS), o Gerenciador de Tarefas em computadores com Windows ou o comando top no Linux.
Você também pode acessar os dados do processo a partir de seus próprios programas. O módulo ...
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.