I saw an interesting interview question today when I was brushing up on my interview questions.
How can a 1000T file be transferred from Nanjing to Beijing at the fastest speed?
network transmission
First we consider transmission over the network and how long it takes.
I made a point of consulting with my classmates who work for the carriers about the current bandwidth:
- Home broadband up to 1Gbps downstream and 300M upstream
Enterprise-class leased lines are divided into data leased lines and Internet leased lines: - dedicated data line (computing)
Maximum 100Gbps, price as low as 35W/month - Internet Private Line
Maximum 10Gbps at 54W/month
Now let's assume we're using an enterprise-class data line.
Actual transmission rate.
100Gbps/8 = 12.5GB/s
One hour can transfer data:
12.5GB/s*3600s = 45000GB
Transferring 1,000 terabytes of data would take roughly
1000/45 ≈ 22.222 hours
That is, you need to1It takes more than days to transmit.
But a dedicated data line can only transmit data, data point to point.
If you use a dedicated Internet data line, you will probably need10Days.
If you're using home broadband, then expect it to take a couple of months.
To be really fast, you have to think about those millions of dollars a year in internet usage.
Is there a quicker and easier way to do this other than that (mainly to save money)?
Must have!
human courier law
In fact, the fastest, most cost-effective method is the human courier method that
With 63 (1000/16=62.5) 16T hard disks on your back it takes about 5 hours to get to Beijing by high-speed train.
Including 2 hours of transportation time on both sides, which means a total of roughly 7 hours of travel time, the
It's not that much longer by plane.
Round trip by high-speed rail, 464*2=928.
Counting cab fare both ways, it's 1100.
And the millions of dollars a year it costs to use the network.
That's a real nice smell for the road!
This is definitely not Mr. Pang being amusing!
Take a look at the rationale:
So never underestimate the bandwidth of a high speed train full of disks racing down the railroad tracks!