Seagate Technologies 80134 ST11M 11R Printed Circuit Board

Seagate Technologies 80134 ST11M/11R BIOS Main Printed Circuit Board is an ISA-bus hard-drive controller PCB designed to work with Seagate ST11M and ST11R drives, part of Seagate’s ST11 family that provides the interface for ST412-era hard disks. The board carries the 80134 part number and is described as a BIOS main printed circuit board for the ST11M/11R controller, featuring a 34-pin drive interface cable connector and an ISA host interface to the computer. It includes a ROM-based Seagate ST11 BIOS (revision 2.1) and firmware; documentation associated with ST11M/11R controllers notes BIOS ROM configurations in 8K or 16K sizes, and this board aligns with those ROM variants. This PCB is commonly used as a spare or replacement part in vintage Seagate ST11M/11R installations and is intended for legacy drive ecosystems rather than modern storage interfaces, making it suitable for restoration or maintenance of older systems that rely on the ST412-era controller framework. The ST11M/11R family is an RLL controller line, and boards like this provide the essential BIOS decoding and drive communication needed to operate the corresponding Seagate drives when connected via the 34-pin control interface and the ISA bus.