Mailing Disks is Faster than Uploading Data

CowboyRobot writes "Who would ever, in this time of the greatest interconnectivity in human history, go back to shipping bytes around via snail mail as a preferred means of data transfer? Jim Gray would do it, that's who. And we're not just talking about Zip disks, no sir. We're talking about shipping entire hard drives, or even complete computer systems, packed full of disks. David Patterson (one of the developers of both RISC and RAID) interviews ACM Turing Award winner Jim Gray." Back in school we always had a saying, "Never underestimate the bandwidth of a station wagon filled with backup tapes." Seems like that still holds true.

Comments

Classic exam question.

[Jason1729]

On our Distributed Systems final, we had a question about using an airplane full of CDs being used to replace our school's internet connection. The point was the even though the plane offered 10,000 times more bandwitdh, the 80 minute latency meant it wasn't a viable replacement.

Jason
ProfQuotes

The telecom industry is to blame.

[jdehnert]

Chips have gotten faster. Ram is bigger faster and less expensive. Disk space is dirt cheap.

But the telecom industry is just crawling in comparison. I use the same phone line for dial up now as I did 10 years ago, and things like ISDN, DSL, and Cable Modems get you better performance, but nothing stellar. I don't think a T-1 has really changed in cost for a very long time.

Funny, when the bubble was expanding all the talk was about the bandwidth we were suppored to have access to, but it never made it to my house.

Eschew Obfuscation

Re:Well, depends on what way you look at it.

[captain_craptacular]

Lets see, local cable modem is $39.95 for 5 gigs and $10 a gig past that. So if you can ship 3 160GB HDD's for $30 thats:

160GBX3 = 480GB / $30 = 16 GB/Dollar

Cable modem = 1GB/$10 = 1/10 GB/Dollar

So the mail is cheaper. And probably faster if you consider how long it would take to DL 480GB @ 32KB/sec compared to next day or 2nd day air.

The bandwith is there, you just can't have it.

[twitter]

Netflix has made a business out of shipping data via snail mail, since the bandwidth isn't really there yet to do it over the internet.

What a great example you picked! Cable TV companies are pumping dozens of digital movies accross their system at once, live. Yet they crimp your upload speed to DSL rates or lower, 30KB/s, because they are afraid of people "stealing" movies. This is not a technological problem, it a social one. Big publishers and telcos are afraid of competition and are doing everything in their power to keep you from enjoying technology that's already in place. It's the same old fight Ma Bell used to wage back when they would not alow you to so much as plug a modem into your phoneline.

How long are people here in the US going to put up with this monkey business?

And the stationwagon bypasses the firewall too

[cait56]

Not only does a stationwagon full of harddrives have a respectable sustained throughput rate, the contents don't get screened by the firewall. Ditto for the hardrives in a briefcase, or those USB drives on a keychain.

Exploding capacities of storage drives have implications on attempts to keep data within boundaries, as well as attempts to getting it from point A to point B.

Re:Tapes too...

[pclminion]

That figure is per tape, the actual shipment has 1,139 tapes, I think. 10.175GB * 1,139 = ~11.6TB. That *is* impressive bandwith.

Well in theory, that's not really "bandwidth," it's just a number of bytes. The bandwidth would be the maximum sustained throughput. Essentially, how much data could be delivered per second, if there were a constant stream of trucks pulling in, each carrying 11.6TB. Assume the trucks drive bumper-to-bumper, at 60 MPH. Assume each truck is what, 25' long. At 60 MPH it takes about 0.28 second to travel one truck-length. Therefore, the actual bandwidth is 11.8/0.28 = 42.1 TB per second.

Re:No, not even close

[sn00ker]

Containerise them. Lift the entire container off the back of the truck in one hit and off the truck goes again. You could cut unload time down to a couple of minutes.
Reminds me of the supermarket distribution plants. Trucks are allocated time slots that are 10 minutes long, and the trucks must arrive exactly on time or they miss out. One forklift unloads the entire truck, and another shifts the pallets into the shelving system. The one nearest me has 20 bays and runs 24x7.
Never underestimate the ability of a logistics facility to chew through trucked goods.

Offload them to where?

[autopr0n]

At some point you have to actually get the tapes into the computers. Even if the tape drives themselves had relatively infinite bandwidth, it would still take at least 10 seconds to get it off the truck and loaded into the reader. Maybe you could save time by using some sort of SUPER GIANT SPOOL like 2 meters in diameter and height.

Imagine that, cassettes the size of shipping containers. Of course, if we're going to talk about things like that, we really need to talk about tape read speed too. Lets say the tape thickness is 8 microns. In that case, each layer can hold (4-(8*10^-6)*i)*pi where i is the layer number, So the total number of layers is Sum(2*(2-(8*10^-6)*i)*pi) (2*pi*r where r is 2m - 8um*i) for i from 0 to 2/8*10^-6. that gives us about 4*10^11 meters of tape. Even if we spun the tape at the speed of light it would still take 20 minutes to read one tape. At the speed of light, it would take about 1309 seconds to load the data into the computer. Since 1309/100 is 13.9, assuming you did your math right the cost would be $278 million per year. Of course, we can't actualy spin the tapes at the speed of light.