Front panel switches - what did they do?

[Paul Berger]

On 2016-05-24 4:13 PM, Chuck Guzis wrote:
> On 05/24/2016 11:39 AM, Eric Smith wrote:
>> On Tue, May 24, 2016 at 12:25 PM, Paul Koning
>> <paulkoning at comcast.net> wrote:
>>>> On May 24, 2016, at 2:07 PM, Chuck Guzis <cclist at sydex.com>
>>>> wrote: ...and the "transformer" ROS used on the 360/40 (and
>>>> others).
>>> You mean "Core rope memory"?
>> IBM's TROS and Core Rope Memory use the same principle, but the
>> physical construction is significantly different. Core rope memory
>> was very labor-intensive to manufacture, while TROS was not.
> There's a photo here;
>
> http://www.cs.sun.ac.za/museum/memory.html
>
> I seem to recall that reworking the 360/30 microprogramming was
> preferred by tinkerers over the 360/40 was primarily that CROS was
> easier to work with than TROS.
>
> I don't recall what the RCA Spectrolas used.
>
> --Chuck
>
>
>
The CROS cards used in a 360/30 where the same size as an 80 column card 
on purpose so you could you a keypunch machine to program the microcode.