OpenBSD Stories: Strange Medieval Devices
summary
Maintaining and operating legacy SMD (Strange Medieval Devices) disks on old Sun Microsystems hardware requires overcoming significant hardware degradation and deep-seated software bugs. The author demonstrates that while these high-capacity drives from the 1980s can be revived, they are plagued by physical wear and outdated driver logic that often goes unnoticed for decades. Successful operation requires a combination of low-level formatting, manual driver patching, and an understanding of the PROM monitor's specific limitations.
key points
- SMD disks differ from modern SCSI or SATA drives by using separate command and data cables and requiring software-managed bad sector handling, which often leads to I/O errors on aging hardware.
- The author discovered a 19-year-old bug in the OpenBSD xy driver and a PROM monitor I/O size limit of 8216 bytes that prevented systems from booting when filesystem block sizes were increased to 16KB.
- Replacing controllers, such as moving from a Xylogics to a Ciprico Rimfire, necessitates a full low-level reformat of the disks because the disk format is controller-dependent and lacks a standard way to query physical geometry.
who should read it
Retro-computing enthusiasts and operating system developers interested in legacy hardware drivers, SPARC architecture, and the forensic recovery of ancient storage systems.
discussion positive
consensus
Commenters generally appreciate the efforts of OpenBSD maintainers to support legacy hardware, though some argue that Linux should prioritize removing obsolete code to maintain kernel cleanliness. There is a shared recognition of the importance of preserving the ability to read data from old storage devices for archival purposes. The discussion also touches on the technical reasons why older websites lack mobile responsiveness due to missing viewport meta tags.
top insight
A former PLC technician describes using the kinetic energy from spinning down legacy SMD disks to power a short tape loop for graceful shutdowns and critical data writes during power loss. This practical application demonstrates how the physical properties of hardware were leveraged for system reliability before modern battery backups.
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