3 ms·
Let's do some XKCD what-if math because I love doing stuff like this. An average truck can house anywhere between 20,000L to 40,000L [1]. Let's take an average
by adtac 9y ago
Let's do some XKCD what-if math because I love doing stuff like this.
An average truck can house anywhere between 20,000L to 40,000L [1]. Let's take an average 30,000L.
An average truck can also travel at anywhere in between 56 kph to 137 kph [2]. Let's take an average 100 kph.
The tape catridge in the image looks like it's about 4mm x 10cm x 6 cm. And it can store 330 TB.
Let's say we're transfering from New York to San Francisco. That's 4,678 km according to Google.
Total data transferred in one truck = 330 TB * ((30000 L / (1000 L / m^3)) / ((4 mm * 0.001 m/mm) * (10 cm * 0.01 cm/m) * (6 cm * 0.01 cm/m)) = 412500000 TB
Total time taken = (4678 km * (1000 m/km)) / (100 kph * (0.27 (m/s)/kph)) = 173259 s
Bandwidth = 412500000 TB / 173259 s = 2380 TB/sec = 19046 Tbps
For reference, 255 Tbps was the fastest single fibre [3]. This is a good 75 times faster.
Of course, all this comes with a network latency of 2 days.
[1] https://en.wikipedia.org/wiki/Tank_truck#Size_and_volume https://en.wikipedia.org/wiki/Tank_truck#Size_and_volume
[2] https://en.wikipedia.org/wiki/Speed_limits_in_the_United_States https://en.wikipedia.org/wiki/Speed_limits_in_the_United_Sta...
[3] https://www.extremetech.com/extreme/192929-255tbps-worlds-fastest-network-could-carry-all-the-internet-traffic-single-fiber https://www.extremetech.com/extreme/192929-255tbps-worlds-fa...
- sharpshadow 9y agoLovely :'D
- gruez 9y agoYou need to factor in the time needed to transfer the data onto/off the drives.
- jandrese 9y agoIt depends on what you're doing with the data. If you're moving it to some long term archive then you only need to count the write time of the disks at the source, packing time, and unpacking time. If you're planning to actually use the data you need to add in the time need to read the tapes and put them on a usable medium. Once you add in all of the overhead, the network comes out looking much better in comparison.
- Twirrim 9y ago>Once you add in all of the overhead, the network comes out looking much better in comparison. That's a broad assumption. There's a reason why AWS is finding demand for Snowball and Snowmobile. Internet connections just aren't that fast.
- jandrese 9y agoIn total bandwidth the truck is still likely to win, but it won't be a 75x advantage. Closer to 3-4x. Also note that the Snowball/Snowmobile fit into the first use case. They are loaded up then just plugged in on arrival, and even then the total number of enterprises that have used the services is not very large. The multi-day latency on the first packet means you need to be transferring enough data that it would take more than those few days to transfer on a STM-4 or similar. It works out to a tremendous amount of data. Of course if you are an arctic researcher who has collected hundreds of petabytes of sensor measurements and only have a satellite backhaul, then this makes tons of sense. But for anybody with a solid backbone connection the calculus is much less favorable.
- FLUX-YOU 9y agoAlso the risk of the truck having an accident and having to "replay" everything.
- brudgers 9y agoIt is significantly less than the time required to lay the appropriate fiber coast to coast.
- slazaro 9y agoWouldn't the bandwidth be close to infinte? As soon as the first byte gets there, the last byte also gets there. You'd have to account for the length of the truck and separation between consecutive trucks, right? The latency is simpler to calculate for sure.