Qual foi o objetivo do botão turbo?

Question

O que o botão turbo em PCs antigos faz?

    

Answer 1

Do artigo botão turbo da Wikipédia:

The button was generally present on older systems, and was designed to allow the user to play older games that depended on processor speed for their timing.

Os jogos mais antigos geralmente executam programas tão rápido quanto o processador permitir. Como o desenvolvedor projetou o jogo para um processador de 33MHz, desde que o usuário tivesse um processador de 33MHz, tudo funcionava conforme projetado. Uma vez que o usuário atualizou para um processador de 66MHz, o jogo agora rodou duas vezes mais rápido, tornando-o injogável. O botão turbo diminuiria o computador para lidar com esse efeito.

    

Answer 2

Ele trocaria o processador entre 4,77 MHz (a velocidade de estoque de um IBM XT) e a velocidade mais rápida que o processador fosse capaz - geralmente de 8 MHz. Meu palpite é que ele estava alternando entre dois cristais diferentes na placa-mãe, mas eu não tenho uma mobília XT antiga por aí para acompanhar os traços para ter certeza.

    

Answer 3

Boa foto, ela mostra exatamente o mesmo invólucro que eu tinha no meu 386DX:)

[roubado da Wikipedia]

The turbo button changes the effective speed of the system. It usually accomplishes this by either adjusting the CPU clock speed directly, or by turning off the processor's cache, forcing it to wait on slow main memory every time. The button was generally present on older systems, and was designed to allow the user to play older games that depended on processor speed for their timing. Systems could also use the keyboard combination of ctrl-alt-+/-, '-' switching turbo off and '+' switching it on (ctrl-alt-\ to toggle between turbo/normal mode on ITT Xtra machines). Of course, calling it a "turbo" button when its function slows the system down can be a bit misleading, but the button was usually set up so the system would be at full speed when the button was "on". The turbo button was often linked to a MHz LED display on the system case, or to a "hi"/"lo" LED display. While the implementation of the turbo button by manufacturers has all but disappeared, Software Developers have compensated with software replacements. One example is DOSBox, which offers full turbo button functionality. Some modern PCs that support ACPI power management provide an on-screen control for the user to switch a PC's performance state between low- and high- performance modes.