100Mbit calculation

jibbajabba

I feel stupid to ask this (always had trouble with that stuff), but is this right

100Mbps = 100 Megabit per Second

Is the following calculation correct :

100 Megabit per second = 12 Megabyte per second
12 Megabyte per second = 720 Megabyte per minute
720 Megabyte per minute = 43 Gigabyte per hour
43 Gigabyte per hour = 1TB per day
1TB per day = 32 TB per month

Does this sound about right ?

Need to send a customer an email but don't want to sound stupid lol

dynamik

Well, 100 / 8 = 12.5. When you're multiplying it that many times, that extra half a meg adds up.

Also, it looks like you're estimating the GB and TB conversions by dividing by 1000 instead of 1024. I'm not sure how accurate you need to be.

royal

1000 is used in data transmissions.
1024 is used in data storage.

dynamik

Wow, I've never come across "bibits" before. Interesting.

I wonder when the storage vendors are going to get that memo. That practice still irks me.

jibbajabba

dynamik wrote:

Well, 100 / 8 = 12.5. When you're multiplying it that many times, that extra half a meg adds up.

Also, it looks like you're estimating the GB and TB conversions by dividing by 1000 instead of 1024. I'm not sure how accurate you need to be.

Yea I know .. just wanted to see if I get the basics right as I somehow had a brain f*rt

cisco_trooper

Whoever started this crap about not following binary should be banished from technology...This is retarded. I agree with dynamik, this has bothered me for quite a while. I don't like buying a 500GB drive and only getting 465GB because someone DECIDES not to use binary..

JDMurray

cisco_trooper wrote:

I don't like buying a 500GB drive and only getting 465GB because someone DECIDES not to use binary..

The "missing" disk space is due to the file system formatting. NTFS is a fatty of a file system.

dynamik wrote:

Wow, I've never come across "bibits" before. Interesting.

I've only seen these measurements in hardware articles. I don't think they've caught on in the mainstream yet. Probably because no one is sure how to pronounce them.

cisco_trooper

JDMurray wrote:

cisco_trooper wrote:

I don't like buying a 500GB drive and only getting 465GB because someone DECIDES not to use binary..

The "missing" disk space is due to the file system formatting. NTFS is a fatty of a file system.

Yeah, I'm aware of the overhead of formatting, but what I'm talking about is the crap that they actually write on the retail packages, "1GB = 1,000,000,000 bytes"

The hell it does.....

dynamik

Yea, it'll show up as less even before you format it. I think 500gb advertised is something like 465gb in reality.

astorrs

One additional thing to factor into your calculations is you'll want to account for overhead. Multiplying the bandwidth by 0.70 should give you what you can actually expect to get out of the line.

Try to push 10Mb/sec over a 10Base-T connection - just try it (and no cheating by using 100Mb connections and port limiting to 10Mb) you'll be lucky to get above 70-80%.

JDMurray

cisco_trooper wrote:

Yeah, I'm aware of the overhead of formatting, but what I'm talking about is the crap that they actually write on the retail packages, "1GB = 1,000,000,000 bytes"

The "500GB" on the packaging is calculated by 1GB = 1,000,000,000 bytes (10^9 bytes), but the hardware calculates disk space by 1GB = 1,073,741,824 bytes (2^30 bytes).

A 500GB drive, hardware-wise, actually contains 536,870,912,000 bytes. The difference is about a 7.5% increase over the size marked on the packaging.

If the drive contains an even 500,000,000,000 bytes of storage, it's hardware-wise size (unformatted) is about 465.5GB.

What about this do you find disturbing or evil?

And how do you feel about paying $2.99 9/10 at the gas pump rather than an even $3.00? It's all just marketing.

dynamik

You really don't find that to be deceptive?

I don't think any of us are too upset about it since we're accustomed to it, but that's really thrown a lot of novices I know. Say someone needs to back up 500gb of data from a few computers, so he or she buys a 500gb external drive. Coming up 35gb short would really mess things up. Then if they're really confused, there's time wasted researching things on the internet, support calls, RMAs, etc. It just seems to be unnecessarily complicated.

royal

Storage vendors have been sued plenty of times over this due to false advertising.

JDMurray

dynamik wrote:

Say someone needs to back up 500gb of data from a few computers, so he or she buys a 500gb external drive.

If you need to backup 500GB of data wouldn't buy a 500GB drive--you buy a 1TB drive for room to grow. That's like building a storage shed exactly big enough to hold everything you need to store only today with no capacity planning for the future. Only for archive tapes (write-once and store forever) would the exact size matter. And for tapes, their capacities have always equaled what's on the wrapper.

dynamik wrote:

You really don't find that to be deceptive?

I bought my first hard drive 20 years ago, and this "1000 != 1024" argument was happening on USENET and BBSes back then. I don't know of a class action lawsuit that's ever been filed against drive manufacturers for false advertising because of disk space misrepresentation. It's just an inequity that professionals have learned to adjust for.

tiersten

It isn't false advertising. They do tell you that they assume that 1KB is actually 1000 bytes.

dynamik

Heh, that was a hypothetical situation I came up with off the top of my head, and you know users have done things much dumber than that!

I really just made that original comment to be funny. I didn't intend to start a debate or argument over this. It doesn't bother me personally at this point, but I do hear about people who stumble over it from time to time. I think that the OS and HD vendors should have simply agreed on a consistent measurement at the onset and avoided this ridiculous situation. It would probably be kind of disastrous to change things at this point. Who would buy 930gb HDs when someone else is selling a TB?

tiersten

Unless there is an agreement between all the various manufacturers, nobody is going to start using 1KB = 1024. As you said, who would buy a 930GB when everybody else is selling 1TB?

Even if you did manage to convince them to change, people will still complain about the overhead from formatting!