The Early Days

The first computer was an IBM 1401, but in late 1966 a new IBM S/360 was commissioned. which was controlled by IBM's OS MFT Release 4/5. MFT stood for Multi-Programming Fixed number of Tasks which was the ancestor of OS/VS1

Much of the JCL and programming code used then still exists today on z/OS.

The guy is standing in front of a row of Open Reel Tape drives and behind a row of 2311 disk drives. Tapes were usually 2400 feet long and recorded at 1600 bits per inch (bpi) with a 0.6 inch gap between recorded items. The maximum size of a recorded item was 32K.

Each demountable disc had 200 cylinders, each of 10 tracks, with each track holding 3625 bytes.