Back in Slack-land
After running FreeBSD on my file server for a while, the hardware finally started giving out. Sign #1: several reboots required to get a successful boot from the primary hard drive. Given that the fan bearings on the PCI bridge were failing as well, it was time to retire the motherboard and switch to one that’s older, but still functional.
The 8139-based Ethernet is no more, and with it go the attending issues with running Linux. The new setup uses a Tulip-based PCI card that can saturate the 100base-T network without so much as a complaint.