6 Dec
2014
6 Dec
'14
12:48 p.m.
On Sat, 6 Dec 2014, Chuck Guzis wrote:
These are primarily PC distinctions. The HD 3.5"
disk is sold with a
nominal raw capacity of 2.0MB. In other words, if you assume a 300 RPM
Yes, we are talking about "formatted capacity" with a very arbitrary
format.
Q: which manufacturer called their 2.8M drive "4M", and quoted the
unformatted capacity?
But a "360K" 5.25" disk is formatted in
PC terms as tracks of 9 sectors
of 512 bytes or 720 sectors total or exactly 360 * 1024 bytes. So far
so good.
. . . and, of course, other choices of format parameters, even sticking
with MFM, can lead to 300K to 440K.
"360K" became a relatively unambiguous way to describe it, so long as one
acknowledges that that is in terms of the most prevalent format in use.
I take hard drive capacities as stated as
more-or-less; not exact. It's
been the case since the manufacturers started putting printed defect
maps on the drives.
It was always interesting to note that FDISK used Mebibytes, wheras other
utilities in the same OS used 1,000,000, or even the bizarre 1,024,000