Reiability of wrong media (was: is out of 5-1/4" diskettes - test-drb@ccmp.vtda.org

21 Jan 1999

-----Original Message-----
From: Pete Turnbull &lt;pete(a)dunnington.u-net.com&gt;
To: Discussion re-collecting of classic computers
&lt;classiccmp(a)u.washington.edu&gt;
Date: Friday, 22 January 1999 20:28
Subject: Re: Reiability of wrong media (was: is out of 5-1/4" diskettes

...
 As Megan pointed out, the maths is wrong.  A
"1.44MB" disk has 80
cylinders, two sides, 18 sectors per track, sector size 512 bytes.

80 * 2 * 18 * 512 = 80 * 18 * 1024 = 1440KB

That's where the "1.44" number comes from.

And a Megabyte is normally held to be 1024 * 1024 (megabyte would, I agree,
be different, 1000 * 1000).  But "1.44MB" refers to 1.44 * 1000 * 1024,
which is a ridiculous way to count.  1440KB = 1.406MB. 

I always thought there were things about IBM that just didn't add up.

(Sorry, couldn't resist it.)

Cheers

Geoff Roberts
Computer Room Internet Cafe
Port Pirie
South Australia.
netcafe(a)pirie.mtx.net.au