Busy loops for delays used to be common. That is why some old PCs had a "turbo mode" switch. When on, the system ran at full speed. When off, it slowed down to

Busy loops for delays used to be common. That is why some old PCs had a "turbo mode" switch. When on, the system ran at full speed. When off, it slowed down to match timing of old games etc. On a DOS PC, a better way to delay would be to count timer interrupts.