There has been a 3 inch format of diskettes in the era of the home computer,
they were used by Amstrad in a dedicated word processing machine and in
their home computers. These disks were monstrously expensive, about 8 euro's
or dollars, or 18 guilders or > 5 pounds sterling EACH! It was possible to
use a conventional "3.5 inch" disk drive as an external device; hower, these
disk drives still burned a very large hole in one's pocket in that era,
although the disks were much cheaper already!
Han
----- Original Message -----
From: <[EMAIL PROTECTED]>
To: "U.S. Metric Association" <[EMAIL PROTECTED]>
Sent: Saturday, May 05, 2001 11:04 AM
Subject: [USMA:12648] Re: Bill Roland again
<snip>
Chris wrote in USMA 12648:
I believe the design of wafers went to metric with the 100 mm version.
Like diskettes, they had previously been hard-imperial (I think 2.5"
was the last in this series) and so the new sizes still got referred
to in old terms. This extended for many years and included the 8"
wafer. Though the 300 mm wafer was often referred to (particularly in
the press) as 12", it seemed about this time that the metric
descriptions entered common currency.
As for IC pitches: I don't think we'll see 0.1" converted to 2.5" (a typo?
2.5 mm) for
legacy reasons, but as the latest small-pitch packages are in hard metric
they will
eventually become the norm.
Chris
UK Metrication Association: http://www.metric.org.uk/
