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

Function of the card:
Alloy – Driver, Prolay One Read Gate

Listed in 1401 SMS card usage

Germanium alloy transistors were an early type of transistor, faster than the earlier grown-junction transistors.

Part number: 371433

Used in: IBM 729II/V, IBM 7090

IBM SMS card type BKVZ 371433 IBM SMS card type BKVZ 371433

Image courtesy of Henk Stegeman

This page created by Ken Shirriff on Wed Sep 15 18:15:09 2021.

The information on these pages comes from a variety of sources, especially old IBM documents on, 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.