I recently came across a dual-height Dilog DQ153 Qbus card and a card
with "Sigma Information Systems" near the bottom edge, and "scsi 1.87B"
hand written on an EPROM chip label. I would guess that the Sigma is a
scsi controller card, but  I'm puzzled about the Dilog....what is this??

Any more information about the Sigma would be appreciated as well.....

TIA.....

Stan