Weird backplane pattern

[jassuncao]

Hello all,
While I was tidying  up my workshop I found an backplane PCB from an old computer  with the following pattern (sorry for the crappy photo)


I assume these are ground guards to avoid crosstalk but it's the first time I saw this kind of pattern in a motherboard. Is my guess correct?
Thank you in advance.

[Simon]

can I hazard a guess that this is on the back of an ATA port ? 80 pin ata ports go up to 133 MB/s rather than the 33mB/s on the 40 pin ports simply because every other wire is a ground and avoids cross talk like you say.

[jassuncao]

This is not an ATA port. From the type of connectors I assume it's a ISA or MCA  backplane from a late eighties server. I guess the designer made an extra effort to minimize cross talk in a <20MHz bus

[T3sl4co1l]

Yeah, reduces electrostatic coupling a little.  Wouldn't be great for rise times in the < 2ns range, but would be fine for anything CMOS/TTL back in the '90s or earlier.

Tim