如果你曾经尝试过让一款老式电脑游戏在现代系统上运行，你可能会对这款游戏的运行速度感到震惊。为什么老游戏在现代硬件上失控了？

今天早些时候，我们向您展示了如何在现代计算机上运行旧软件；今天的问答环节是一个很好的补充，它深入探讨了为什么一些旧软件（特别是游戏）在现代硬件上运行时似乎永远无**常工作。

今天的问答环节是由SuperUser提供的，SuperUser是Stack Exchange的一个分支，是一个由社区驱动的问答网站分组。

问题

超级用户读者TreyK想知道为什么旧电脑游戏在新硬件上运行得如此之快：

I’ve got a few old programs I pulled off an early 90s-era Windows computer and tried to run them on a relatively modern computer. Interestingly enough, they ran at a blazing fast speed – no, not the 60 frames per second kind of fast, rather the oh-my-god-the-character-is-walking-at-the-speed-of-sound kind of fast. I would press an arrow key and the character’s sprite would zip across the screen much faster than normal. Time progression in the game was happening much faster than it should. There are even programs made to slow down your CPU so that these games are actually playable.

I’ve heard that this is related to the game depending on CPU cycles, or something like that. My questi*** are:

• Why do older games do this, and how did they get away with it?
• How do newer games not do this and run independently of the CPU frequency?

那是怎么回事？为什么旧游戏中的精灵在屏幕上燃烧得如此之快以至于游戏无法玩？

答案

超级用户contributor JourneymanGeek将其分解为：

I believe they assumed the system clock would run at a specific rate, and tied in their internal timers to that clock rate. Most of these games probably ran on DOS, and were real mode (with complete, direct hardware access) and assumed you were running a iirc 4.77 MHz system for PCs and whatever standard processor that model ran for other systems like the Amiga.

They also took clever shortcuts based on those assumpti*** including saving a tiny bit of resources by not writing internal timing loops inside the program. They also took up as much processor power as they could – which was a decent idea in the days of slow, often passively cooled chips!

Initially one way to get around differing processor speed was the good old Turbo button (which slowed your system down). Modern applicati*** are in protected mode and the OS tends to manage resources – they wouldn’t allow a DOS application (which is running in NTVDM on a 32-bit system anyway) to use up all of the processor in many cases. In short, OSes have gotten **arter, as have APIs.

Heavily based off this guide on Oldskool PC where logic and memory failed me – it’s a great read, and probably goes more in depth into the “why”.

Stuff like CPUkiller use up as many resources as possible to “slow” down your system, which is inefficient. You’d be better off using DOSBox to manage the clock speed your application sees.

如果你对早期电脑游戏中的实际代码是如何实现的感到好奇（以及为什么它们对现代系统的适应能力如此之差，而没有在某种模拟程序中进行沙盒处理），我们还建议在另一个超级用户答案中查看这个冗长但有趣的过程分解。

有什么要补充的解释吗？在评论中发出声音。想从其他精通技术的Stack Exchange用户那里了解更多答案吗？在这里查看完整的讨论主题。