View Full Version : IBM 360-era supplemental control panel device

May 29th, 2010, 07:07 PM
OK. I could not resist this from a recent Ebay auction. Now, what the heck is it?

Note that there are two rows of 18 DISPLAY lights with a set of 18 3-way toggle switches below them. The IBM 360 was a 36 bit word machine (18x2)

The inside of the unit reveals a set of IBM Solid Logic Technology (SLT) chips.

Here is my theory - This is a device used for validating data or comparing data before and after passing through from one unit to another. I know that back then IBM had large I/O controller units that would help bridge more than one 360 processing unit, or multiple storage unit. They may have needed to verify when a new piece was installed correctly, and that the data was not accidentally reversed (cabled backwards) I am thinking that IBM used these to help analyze the data, perhaps allowed him to single step through a program.

I should add that this was purchased from a seller who also owned an IBM 360 front panel.

Anyone have any theories? I have plenty more pictures here:

May 30th, 2010, 11:52 AM
you should ask on the cctalk list, i'm certain someone will have a good suggestion. Your theory sound pretty believable though, with all them input wires. Maybe it was used for some kind of fault monitoring/tolerance. Perhaps an early version of a logic analyser.

June 2nd, 2010, 07:01 PM
Actually the 360's were 32 bit words :-) Univac 1100's were 36 bit.
Can you post a photo of some of the labels under the switches? Quite often the mainframes of the day had diagnostic/exerciser boxes. Even the 1700 series keypunches from Univac had a box with toggle switches so that we could 'exercise' the logic during troubleshooting


June 3rd, 2010, 09:27 AM
Here is a link to a highly detailed picture of the front panel.


Thanks for setting me straight on the bit words, I looked it up and thought it was 36 bits for whatever reason, but double checking on Wikipedia and I see now it's 32 bits. Wonder how I made that mistake, oops.