NCR Century 100

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[edit] NCR Century 100

NCRs first all integrated circuit computer. The 615-100 Series integrated a complete data processing system had 64MB of short rod memory, 80-column card reader or paper tape reader, two 10MB removable disc drives, 600-line per minute printer. 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 load a program you entered a hexadecimal boot strap code by setting the rotary switches. This would read a set of boot four cards that load programs from the boot disc.

[edit] Dancing Rods

The memory of the Century Series used a short (1/16 inch long) rod instead of cores. These were inserted into a plastic alignment sheet. To get the rods stand up straight in the sheet for wiring a large electro-magnet was turned on and made the rods ‘dance’ into individual holes.

[edit] Flying Discs

The removable disc drives were the first to employee floating or Flying head. The Marketing material made a big this of this, but there were a number of problems that plagued all of the Century Series systems. Head crashes were common because the head flew a less than a human hair above the disc surface. And, unless a drive unit was repaired and carefully cleaned after a crash, the next disc pack to load would also crash. If a crash disc pack was loaded on a operational drive, it could destroy the drive unit.