3 ms·

That phenomenon is the source of one of my all-time favorite man page entries: https://web.archive.org/web/20210421224904/https://nixdoc.net/man-pages/FreeBSD/m

That phenomenon is the source of one of my all-time favorite man page entries: https://web.archive.org/web/20210421224904/https://nixdoc.net/man-pages/FreeBSD/man4/i386/ep.4.html https://web.archive.org/web/20210421224904/https://nixdoc.ne... ep0: 3c509 in test mode. Erase pencil mark! This means that someone has scribbled with pencil in the test area on the card. Erase the pencil mark and reboot. (This is not a joke). It's the E1 pad between the barcode and the empty BIOS socket: https://en.wikipedia.org/wiki/3Com_3c509#/media/File:3Com_3C509BC_Ethernet_NIC.jpg https://en.wikipedia.org/wiki/3Com_3c509#/media/File:3Com_3C...

drewzero1 4y ago
That's awesome! I have a handful of those 3Com cards kicking around at work. Will definitely have to check that out.
solardev 4y ago
Hah, that's really great! Does that mean they used that to switch it into a test mode during development?
- jonah-archive 4y ago
  Pretty much -- IIRC connecting the pad bypasses the internal EEPROM and loads a default configuration, and from there you can read/write the EEPROM as well.
  - jonah-archive 4y ago
    ah, found it! Page 88 of this PDF: https://www.ardent-tool.com/NIC/3c5x9b_Technical_Reference.pdf https://www.ardent-tool.com/NIC/3c5x9b_Technical_Reference.p... ---------------------------------------- It is the user’s responsibility (with help from the configuration program) to avoid configuring the boot PROM on the adapter in such a way that the system is not able to boot. If this does occur, you can manually jump the Test Via using a #2 pencil. The Test Via forces the adapter into test mode, which disables the boot PROM so that the adapter configuration program can be run. You must cover the designated area thoroughly with the pencil mark. Test mode forces the adapter not to perform the Automatic Initialization sequence, which means the EEPROM is not read and the adapter is left in the following configuration: ■ Address Configuration register = 0000h ■ Resource Configuration register = 0000h ■ Product ID register = 0000h Test mode also shortens the ID sequence to 8 bytes (first is still FFh and last is 69h) and forces it to the active state (that is, the adapter is active and will respond to I/O cycles at base address 0200h even without going through the ID sequence). After you are done, thoroughly erase the pencil mark. ----------------------------------------
    - solardev 4y ago
      This is amazing and hilarious at the same time. Thanks for sharing!

drewzero1 4y ago

That's awesome! I have a handful of those 3Com cards kicking around at work. Will definitely have to check that out.

solardev 4y ago

Hah, that's really great! Does that mean they used that to switch it into a test mode during development?

jonah-archive 4y ago
Pretty much -- IIRC connecting the pad bypasses the internal EEPROM and loads a default configuration, and from there you can read/write the EEPROM as well.
- jonah-archive 4y ago
  ah, found it! Page 88 of this PDF: https://www.ardent-tool.com/NIC/3c5x9b_Technical_Reference.pdf https://www.ardent-tool.com/NIC/3c5x9b_Technical_Reference.p... ---------------------------------------- It is the user’s responsibility (with help from the configuration program) to avoid configuring the boot PROM on the adapter in such a way that the system is not able to boot. If this does occur, you can manually jump the Test Via using a #2 pencil. The Test Via forces the adapter into test mode, which disables the boot PROM so that the adapter configuration program can be run. You must cover the designated area thoroughly with the pencil mark. Test mode forces the adapter not to perform the Automatic Initialization sequence, which means the EEPROM is not read and the adapter is left in the following configuration: ■ Address Configuration register = 0000h ■ Resource Configuration register = 0000h ■ Product ID register = 0000h Test mode also shortens the ID sequence to 8 bytes (first is still FFh and last is 69h) and forces it to the active state (that is, the adapter is active and will respond to I/O cycles at base address 0200h even without going through the ID sequence). After you are done, thoroughly erase the pencil mark. ----------------------------------------
  - solardev 4y ago
    This is amazing and hilarious at the same time. Thanks for sharing!