Almost sounds like urban legend but it's right on. They also served on
the DisplayWriter dedicated word processing machine.
The updating of firmware on IBM gear has gone through many technological
evolutions. One of the earliest technologies that I recall was CCROS or
Card Capacitor Read Only Storage. You can find it described here about
1/3 down the page:
<http://www.staff.ncl.ac.uk/roger.broughton/firmware/uprog.html>
in brief:
"For the Model 30, Card Capacitor Read-Only Storage (CCROS) was
developed. This technology was based on mylar cards the size and shape
of standard punch cards that encased copper tabs and access lines. A
standard card punch could be used to remove some of the tabs from a 12
by 60 bit area in the middle of the card. Removed tabs were read as
zeros by sense lines, while the remaining tabs were read as ones. An
assembly of 42 boards with 8 cards per board was built into the Model 30
cabinet."
Capacity is a whopping 20 KB or thereabouts but you could update the
memory with a punch card machine. :-)
Chuck Norcutt
Moose wrote:
>
> Do you know how floppies originated? IBM was making controllers for its
> SNA remote distributed processing systems and need a way to
> distribute/boot/update the firmware. They invented a magnetic portable
> medium for that use, which was the first 8" floppy. I remember when my
> brother was adapting 8" floppies as mass storage devices for TRS-80s.
>
> Moose
==============================================
List usage info: http://www.zuikoholic.com
List nannies: olympusadmin@xxxxxxxxxx
==============================================
|