Expert Witness Forensic Engineer Industrial Controls Automation New Orleans
Arthur Zatarain
Product Development
Interfaces to Legacy Computer I/O Devices

Product development: A wide variety of microcomputer-based interfaces were produced to allow continued use of legacy computer I/O devices such as IBM punch card readers. Some systems interfaced with the existing device control system, while other systems used the new micro to replace the existing controller. The systems were based on COTS components for the microcomputer portion which was mated to custom-built interface boards for each legacy device.

The first interface was developed in 1980 to connect a high speed punch card reader to an Alpha Micro AM100 multi-user computer. The serial link between the reader and AM100 was performed by a single board Z80 micro with a custom-built opto-isolated digital and analog board. That system was later upgraded to a SCSI interface for the AM100, and eventually migrated to both serial and SCSI for PC class computers. The system processed many millions of punch cards until it was retired in the mid 2000's.

Subsequent legacy interfaces used similar concepts to mate old equipment with new computers. A sample of I/O systems that got a second lease on life included:

9 Track Magnetic Reel Tape Drive
Magnetic Cartridge Tape Drive
CDC Phoenix Disc Drive
DEC Mag Stripe Card Reader
IBM & DEC Punch Card Readers
Medical Lab Patient Tracking Sys.
Remote Weather Station
Circular Chart Gas Flow Integrator

ITT 600-LPM Line Printer
Mag Tape Retrieval Robot
HP Digital/Analog I/O Unit
Paper tape punch/reader
Building Automation System
Wire Service Phone Line Interface
Radio Station Tape Cartridge Player

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