High Quality Content by WIKIPEDIA articles! The NCR Century 100 was NCR's first all integrated circuit computer. The 615-100 Series integrated a complete data processing system had 16KB or 32KB of short rod memory, 80-column card reader or paper tape reader, two 5MB removable disc drives, 600-line per minute printer. You could have a punched paper tape reader, or you could have an external card reader/punch. The system also allowed for the attachment of multiple 9 track 1/2 inch reel to reel magnetic tape drives. You could attach at least 2 more disk drives to the unit. All logic gates were created by wire-wrapping nand gates together to form flip-flops and other complex circuits. The console of the system had only 18 lights and switches. To start the machine you entered a hexadecimal boot strap code by setting the rotary switches. This would read a set of four boot cards that loaded the B1 operating system programs from the boot disc. A typewriter console was also available. The rotary switches also could be used to patch programs. That is, you could modify commands and program logic by entering information through the rotary switches. The computer had a clock that ran, and since most computers of the era were rented, NCR gave you so many hours a month of usage before you had to pay more. To keep the meter from running there was a halt switch, so if you wanted to either halt the current program or to simply stop the meter from running, you would put the switch in the halt mode.