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IBM System 3: Predecessor of the Modern Server

IBM System 3

IBM System 3

Pedro Trebbau Lopez

The IBM System/3, introduced in 1969 and discontinued in 1985, was a cheap IBM computer for office tasks aimed at new customers or organizations that still maintained computers or IBM accounting machines of the 1400 Series. It was the first member of the family that IBM called Midrange. These computers are known currently as minicomputers and servers.

It implemented a new punch card format that stored 96 characters. Instead of the classic rectangular perforations of IBM cards the new card had small holes 1 mm in diameter, similar to those that a punched tape had. The data were stored in six-bit BCD format, with columns of 32 characters each, or eight bits in EBCDIC format with two additional holes located at the bottom of the columns.

The cards held 128 characters printed in 4 columns of 32 characters each. The IBM System/370, with an appropriate card reader, could also process the new cards.

Many units of the System/3 Model 10 were sent only with the original I/O punch card (reading, punch and management ) and a printer. There were two card reader models . The most common was known as MFCU or Multifunction Card Unit which read, punched and sorted new cards of 96 columns. The second model, less common, was the MFCM or Multifunction Card Machine, performing the same operations, but only with the most common cards of 80 columns. The MFCM was provided to large companies that already had equipment for 80-column cards . There were 3 models of different speeds: 100ppm , 200ppm and 300ppm . The printers were offered in several model.


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