This is a full length WD33C93 Zorro II SCSI-2 card similar to the GVP A2000-HC and the original SCSI+RAM products. This card provides for 2mb memory expansion installed as standard 30-pin SIMMs. It used a 16K SRAM buffer for the 33C93A to DMA to/from, and the CPU moves the data to/from the destination via that on-board buffer.
Jumpers
J2 (removed) enables the 2MB AutoConfig FastRAM.
J4 enables the boot EPROM socket(s).
J5 is a test jumper (disables the SRAM, which causes the driver to not find any SCSI drives)
The board is upgradable to the single v3.x FastROM from the original V1.0 or 2.x dual ROM configuration. U30 takes the single v3.x FastROM EPROM as long as PAL U42 is checksum 4711. A dual-ROM version of the driver is available if this updated PAL is not installed. Either ROM format of the FastROM driver can be found and programmed from the download link of driver-writer's website.
Unofficial Notes: U50, J6, J7, J8, and the RN16 components were left off. These would have given options for a 14MHz 33C93A, but the 1.0/2.x driver was not going to be able to support it at the time. The 3.x driver came out after the board was in the field, but no plans were made to test a 14Mhz mode as the performance improvement was expected to be minimal (over the already improved v3.x driver), and the 3.x FastROM was able to compensate for the SCSI Disconnect/Reconnect issues that existed in all revisions of the 33C93 SCSI chip anyway. Most boards shipped with the non-A version of the SCSI chip (-02), which only suports <8MHZ clocks. The GVP 1.0/2.x ROMs executed from the card. The 3.x ROM transfers itself into first available FastRAM (if available) for best possible execution performance.
Trivia: This board, like the original Impact SCSI+RAM 8/x has a cosmetic AutoConfig mistake where it's Product ID is 1762 and not 2017. A bit in the AutoConfig math (256) was left out. GVP owns both maker ID's for this reason.