I don't think you can use a SyQuest with a 2090a, but I'm not sure.
I know you can use it with a C Ltd. SCSI (I do) and with the Supra and GVP
(I know people who do). I believe it is a problem with finding a device
driver for use with it. That is no problem with the C Ltd., as it allows
you to design your own drivers. I believe Supra and GVP supply SyQuest
drivers.