IBM System⁄360 Front Panel

I recently acquired this front panel from an IBM 360 mod 50, with lots of switches and over 250 blinkenlights. The IBM System/360 was an iconic mainframe computer introduced in 1964 (see promotional video here: https://youtu.be/V4kyTg9Cw8g). The system was a huge development gamble for IBM, with all the "models" from small to huge sharing mostly the same overall architecture and instruction set, but with radically different hardware implementations depending on the cost and performance point. A key novelty was the introduction of "SLT" ceramic hybrid modules, pre-dating the integrated circuit, but with denser packaging than individual transistors. This front panel is from a model 50 (in IBM speak a "mod 50"), a larger business system. And yes, I'll take you through most of the buttons. Take this with a grain of salt, this is very complicated and I am new at it. Understanding the meaning of every one of the 1,152 bits that the lights and rollers can display will take some serious further study. I am sure the IBM CEs (Customer Engineers) that spent their careers on these panels will chime in the comments section and correct all my mistakes.

Try Ken Shirriff's emulation of a running 360 driving this panel: https://static.righto.com/360/

Ken Shirriff's article about the 360: https://www.righto.com/2022/01/ibm360model50.html

Chapters 00:00 Panel unboxing 00:53 First look, front side 02:28 First look, back side 04:17 Repairs 06:52 Every part of the panel explained! 07:43 Power panel 09:00 Memory panel 09:49 Emergency pull 10:11 Auxilaliary memory power panel 11:05 Channel test panel 11:34 Main indicator panel 12:47 Data and address entry panel 14:21 Error lights panel 15:41 Debug / program flow control switches 17:51 Time counters 18:22 Manual operation and debug panel 20:50 FLT control (firmware test routines) panel 21:51 Start/boot (IPL) panel 23:02 Overall view, flipping rollers, future work

Our sponsor for PCBs: https://www.pcbway.com Support the team on Patreon: https://www.patreon.com/curiousmarc Merch on Teespring: https://teespring.com/stores/curiousmarcs-store Learn more on companion site: https://www.curiousmarc.com Contact info: https://www.youtube.com/curiousmarc/about