Tag / Tips

by Greg

Bits vs Bites … Scam

I have already learned that there is a difference between a bit and a byte. That’s why when you buy a hard drive that says it’s 1 TB … you’re actually only getting 976.56 GB. Or something like that. Because one kilobyte is 1024 bits, and one megabyte is 1024 kilobits, etc.

For some reason I forgot to apply that to bandwidth estimates.

I’ve always been seriously annoyed by my ISP’s claims regarding my available bandwidth. I use their speedtests and I see that the results are close to (have even exceeded) their numbers, but I also check it against the various bandwidth measuring tools I have on my computer. I am supposed to have at least 1 MBps upload speed and up to 20 MBps download speed… but the best I get is about 133KBps upload and 2-3MBps download. What gives??

Well, “what gives” is that the difference is a factor of 8.

Yes, ladies and gentlemen, what my computer is telling me is the BYTES version and what our ISPs tell us is the BITS version. Ugh. I know it’s not really a “scam”, but it feels like it! They inflate their numbers 8-fold!

For example, a 256Kbps (kilobits per second) upload speed is only a 32KBps (kilobytes per second) upload speed. Those numbers are very different. Let’s apply that to the 1MBps speed (would be 1024KBps) I thought I was getting (which is actually only advertised as 1Mbps, capitalization being very important…) and I end up with 128KBps. (Which is about what I get!)

So there is truth in advertising!

Problem is, who actually knew that capitalization could be so important? I now understand. It now makes sense.

It still irks me a bit. (Or would that be a byte?)

For further study, see: http://en.wikipedia.org/wiki/Bit.

by Greg

Mac Tip: Repair Permissions

For some reason, this little feature in Mac OS X 10.5 Disk Utility (and previous iterations of OS X) keeps popping up as a solution lately. I thought perhaps readers of this blog might benefit from a little reminder, and quick tutorial for performing this routine maintenance task.

First, what it is not. It is not “defragging” your computer. (Spell check doesn’t like that word.) Windows users frequently ask for a way to do such a thing on the Mac, but to my knowledge there is no way built into Mac OS X to do such a thing, other than what happens at log in. Mac OS X does perform similar tasks each time you log in to your computer.

What it does do is explained in this support article from Apple. I don’t completely understand it, but what it does seem to do is take care of “quirks” that pop up every now and again. It could be a computer that seems slow, or files not behaving the way you think they should… I have prescribed it a lot recently, and it seems to do the trick.

How it’s done:

  • Open the application Disk Utility (find it using Spotlight, or go to Applications > Utilities > Disk Utility
  • Select your hard drive from the list on the left side of the window.
  • Click on “Repair Permission” button near the bottom middle of the Disk Utility window.
  • Depending on how often you do this, it could take a few minutes or longer.
  • Disk Utility will let you know when permissions have been repaired. Close it down, and you’re all done.

For good measure, you can log out and back in. (Or restart the computer.)

If you’ve been noticing “quirks”… give that a try and see if it improves performance on a sluggish or quirky Mac!