Whence 556?

[Chuck Guzis]

On 06/04/2018 11:20 AM, Rich Alderson via cctalk wrote:

> For decades, I remembered the lowest density for magnetic tapes as 225 bits/in,
> not 200.  I have never been able to find the number "225" in any manual since
> starting the project which became the museum 15 years ago (sob!), but it still
> hangs around in my mind and pings whenever I see "200BPI" mentioned.

Nope.  I've seen 248 mentioned and I have period-specific tapes that are
declared to be 200 bpi on the label and then there's this:

http://www.digitalheritage.de/peripherals/cdc/604/604.htm

Note the density indicators on this panel from a CDC 604.

--Chuck