Data Transfer Time Question

pro11pro11 Member Posts: 10 ■□□□□□□□□□
Hello everyone,

Decided to go get my CCENT cert (100-105) and currently going through the CBT nuggets videos by Jeremy.
In the Network Fundamentals: Speed, Data Size and Diagrams video he explains how to calculate your data transfer speed using the file size and connection speed.
To assist me in this task I am using a site Jeremy referenced during the video: [URL="http://CalcTool: Data Transfer"][/URL]

In his example:
8 MB file > 100 Mbps (connections speed) = Should take 0.610352 s

Just to practice I found an excel file in my computer with a file size of 25.2 KB.
25.2 KB > 100 Mbps (connections speed) = should take 0.00192261 s according to the site mentioned above.
I tried to complete the calculation manually just to have a better understanding of it and was not able to use Jeremy's calculation, due to the different units (MB and KB).
So here's what I did:
25.2 KB /1024 = 0.0246 B
0.246 B * 8 b = 0.00196875 b
0.196875 b / 100 mbps = 0.00196875 s (the transfer time calculation tool spits out 0.00192261 s, which is only obtained by dividing by 102.4 mbps instead of 100 mbps)

I may be giving this too much importance but just want to make sure I have the correct understanding of it.
Is there an easier way of doing this calculation?



  • dontstopdontstop Member Posts: 579 ■■■■□□□□□□
    Set your data size to KiB instead of KB in the calculator app. Otherwise it will be dividing 25.2 / 1000 and not 1024.

    KiB = 2^10 bytes [1024 bytes]
    KB = 10^3 bytes [1000 bytes]

    Windows will show a file size of 1KB but on disk from my understanding it's actually 1KiB (so the file will have 1024 bits)

    For instance I just made a file in Notepad++ with 1024 characters (8 bits each) and Windows reports "1.00 KB (1,024 bytes)" to be correct it should report based on today's conventions "1.00 KiB (1,024 bytes)".
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