NCR Century 100


NCR Century 100
NCR Century 100 Logo

The NCR Century 100 was NCR's first all integrated circuit computer.[1] 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.

Contents

Dancing Rods

The memory of the Century Series computers used machine made, short (1/16 inch long and approximately the diameter of a human hair) iron-oxide coated, ceramic rods as their random access memories, instead of the hand-labor intensive core memories that were used by other computers of the time. These rods were inserted into a plastic alignment sheet which was wound with read, write, and sense wire coils arranged in columns and rows. To get the rods to stand up straight on the sheet (so that they would drop into the coils for assembly) a large electro-magnet was turned on and made the rods stand up and ‘dance’ into the individual holes.

Flying heads

The Model 655 removable disc drives were the first to employ floating or flying heads. The marketing material made a big thing of this, but there were a number of problems that plagued all of the early Century Series systems. Head crashes were common because the head flew less than a human hair's width 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 crashed disc pack was loaded on an operational drive, it could destroy the drive unit.

A feature of the 655 drives was 12 read / write heads per surface. This reduced track to track movement and thus access times. However, this meant that there were 12 times more heads per drive, further increasing the likelihood of head crashes.

Later NCR went and got different disk units from other manufacturers as the number of head crashes were on at least some machines very common. Oddly, one location could have multiple crashes every day, and another location not have any for years. You always put the removable disc pack in the same drive, which were called D01, D02, D03, etc.

Programming Languages

The NCR Century 100 supported at least two programming languages. The first was Neat/3 which was a later version of the Neat/1 language that ran on the NCR 315 computer system. The second was Cobol. The third was Fortran. The fourth was Basic.

References


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • NCR CRAM — For other uses, see CRAM (disambiguation). CRAM, or Card Random Access Memory, model 353 1, was a data storage device invented by NCR, which first appeared on their model NCR 315 mainframe computer in 1962. A CRAM cartridge contained 256 3x14… …   Wikipedia

  • NCR Corporation — Type Public (NYSE: NCR) Industry Technology …   Wikipedia

  • NCR Corporation — Тип Публичная компания Листинг на бирже NYSE …   Википедия

  • NCR Self-Service — NCR Self Service, a subsidiary of NCR Type Subsidiary Industry Technology Founded 1988, 2004 Headquarters Lake Mary, Florida Key people Theresa Heinz, President …   Wikipedia

  • NCR 304 — computer system Camp Pendleton, California The NCR 304, introduced in 1957, was National Cash Register (NCR) s first transistor based computer. The 304 was developed and manufactured in cooperation with General Electric. Its follow on was the NCR …   Wikipedia

  • NCR Country Club — is a country club located in Kettering, Ohio, where NCR Corporation formerly was headquartered. There are two golf course s at the club, the North course and the South course. The 1969 PGA Championship was played on the South course, Raymond… …   Wikipedia

  • NCR — Para otros usos de este término, véase Nuevo Camino Revolucionario. La corporación NCR es una TIC especializada en soluciones para la venta al por menor y la industria financiera. Sus principales productos son: cajas (puntos de venta en… …   Wikipedia Español

  • NCR 315 — The NCR 315 Data Processing System, released in January 1962 by NCR, [1] was a second generation computer. All printed circuit boards used resistor transistor logic to create the various logic elements. It used 12 bit slab memory structure using… …   Wikipedia

  • NCR VRX — VRX VRX/E VRX is an acronym for Virtual Resource eXecutive, a proprietary operating system on the NCR Criterion series, and later the V 8000 series of mainframe computers manufactured by NCR Corporation during the 1970s and 1980s. It replaced the …   Wikipedia

  • NCR 5380 — The NCR 5380 is an early SCSI controller chip developed by NCR Microelectronics. It was popular due to its simplicity and low cost. The 5380 was used in the Macintosh Plus and in numerous SCSI cards for personal computers, including the Amiga and …   Wikipedia


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.