This page describes the IBM SMS card "DHY", and is part of the SMS card database.

Function of the card:
1 - 8 way, 1 - 2 way w/o load
SDTDL 1-8, 1-2 way -a wo/load

Saturated Drift Transistor Diode Logic (SDTDL) is a form of Diode-transistor logic using faster drift-field transistors.

Part number: 372193

Customer Eng reference number: 734302

Used in: IBM 1311 Disk, IBM 2821 Control Unit

Cap code: None (details)

References: IBM 1311 ILD, p130
IBM 2821 CCD, p63

The information on these pages comes from a variety of sources, especially old IBM documents on bitsavers.org, as well as information from the IBM 1401 restoration team, especially Tim Coslet's SMS data and Jim Hunt's data. Much of this information was obtained through OCR, so don't expect complete accuracy. These pages are not associated with IBM in any way.