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Leaky Bucket problem in Excel

wlerner

New Member
I am an Excel newbie, so please indulge me. :)


I am trying to figure out how to make Excel perform "Leaky Bucket" calculations for me. For example, lets say we have a disk drive (Disk Drive A) that has an I/O speed of 200 MB/s. Let us say that this disk drive writes to another disk drive (Disk Drive B) at 50 MB/s. How long will it take before the first disk drive is full?


This problem is relatively simple, but I am unable to work it out in Excel without using many,many rows. I do not believe I need to use macros or any of the more exotic features of Excel. Regardless, this is driving me mad, so any assistance is appreciated.


Thank you!
 
Wlerner


Firstly, Welcome to the Chandoo.org Forums


Do you mean that Disk 2 is 50MB in size and not that it has an I/O speed of 50MB/s ?
 
Isn't it just


(size_hdd1_in_bytes*8)/(speed_to_hdd1-speed_from_hdd1)-1


and assuming that HDD2 is similar in size to HDD1
 
@dan_l

Hi!

Too much skyrim???

:)

Regards!

PS: wanna get my NFS-TheRun copy to de-stress for a while?
 
ha!


I'm actually on a skyrim vacation until they put out a dlc or the mods get more refined. then I'll start a new character and chandoo.org will be absent a poster for a while.
 
@dan_l

I'm stuck after Las Vegas checkpoint, I can't handle how to drive the most powerful muscle car, a Chevrolet El Camino SS, a straight in the highway without feeding it with guard rails and grass :(
 
Thank you for the valid responses. I really did mean that disk 2 has an I/O speed of 50MB/s.


I have the formula necessary to figure this out. However, I am trying to get Excel to iterate through the formula, using the solution generated on the first iteration as part of the second iteration. This is a time series problem, and I am not sure how to get Excel to do this. Information on the Leaky Bucket is below.


The Leaky Bucket Algorithm is based on an analogy of a bucket (figure 1) that has a hole in the bottom through which any water it contains will leak away at a constant rate, until or unless it is empty. Water can be added intermittently, i.e. in bursts, but if too much is added at once, or it is added at too high an average rate, the water will exceed the capacity of the bucket, which will overflow.


http://en.wikipedia.org/wiki/Leaky_bucket
 
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