Can you explain the concept of pseudo-parallel processes in programming?

Pseudo-parallel processes are a way of executing multiple tasks that appear to run simultaneously, but on the processor, they are executed sequentially. In programming, this is achieved with a task scheduler that quickly switches between processes or threads, creating the illusion of parallelism.

In Go, this is implemented through goroutines — lightweight threads that the Go scheduler runs on one or more system threads. Goroutines can execute pseudo-parallelly, especially if you have a single processor, where tasks switch very quickly.

Example in Go:

package main

import (
    "fmt"
    "time"
)

func say(s string) {
    for i := 0; i < 5; i++ {
        time.Sleep(100 * time.Millisecond)
        fmt.Println(s)
    }
}

func main() {
    go say("Hello") // start a goroutine
    say("World")   // main goroutine
}

Here, two functions execute almost simultaneously, but in reality, Go switches between them quickly, creating the effect of pseudo-parallelism.