I, too, worked on/with the IBM 360 after cutting my programming/compiling teeth on an IBM 1620. {1964, FORTRAN, Hollerith punched card input, dot matrix printer output}
My first computer was in 1972 as a college student learning FORTRAN on a desk sized IBM 1130 with 4 KB RAM, and a 5 MB "pizza size" removable cartridge disk in the desk drawer. Later my first computer I worked on (even doing repairs) during my 37 years in EDP (later IT) was an
IBM System 360/30 (see picture) running DOS with 16 KB RAM, a "washing machine size" removable 10 MB Model 2311 disk drive, two Model 2415 800 BPI tape drices, a Selectric "golf ball" typewriter main console, a Model 28 ASR Teletype secondary console, and two Model 2702 communications control units (using 60 mA current loop mercury-wetted relays) which manged the entire Telegraph System of the Puerto Rico Communications Authority between 1974 and 1981. I do remember the red pull EPO switch, and it was resettable, but you needed the key to open the mainframe face panel and loosen a screw to reset it. The EPO (Emergency Power Off) can also power off the external I/O controllers if the EPO cables (in addition to the Bus and Tag cables) were attached. I still remember the huge "gates" (large internal frames) with gold-plated "point to point" wiring pins and yellow wires on small boards, and plug in modules using RTL (Resistor Transistor Logic) inside square metal cans.
In 1972The PRCA had an IBM System 370/148 running OS/VS with 1 MB of RAM and 300 MB 3350 hard drives, that used the first 8-inch diskettes for MIPL (Microcode Initial Program Load), other modern controllers, and the CRT (3270 class) green screen terminals. It was impressive, instructional, and lots of fun!! In those 37 years (later at PRTC and Claro) I worked with all the IBM mainframes (my last was a impressive seven-foot tall
System z10 running MV in 2011 - see pictures), all the midrange (RS/6000 and Power Servers running AIX), all the xSeries servers (Windows and Linux), and all the PC models from the 5120 IBM Personal Computer (PC/DOS) to the last ThinkStations (OS/2) before Lenovo took the PC market from IBM. All of that is in my past but I really enjoyed working with all that IBM hardware and others brands that are too numerous to write here.
