On Feb 7, 2023, at 12:25 PM, Lars Brinkhoff via cctalk <cctalk(a)classiccmp.org> wrote: Hello, I could use some help making sense of the VAXstation ROM images. A set is provided here: https://www.9track.net/roms/ The two .bin files are each one halfword of a 16-bit wide ROM for the 68000 display processor. I checked it, and it's fine. My problem is with the Bit Blit Accelator. The board has four Am2901 bitslice processors to make up a 16-bit custom blitter. The information I have is that the microcode is 57 bits wide and there should be 1024 words. However, this is not a great match for the rest of the ROM images. Some of the BBA ROMs seem to be bit masks, presumably useful for rendering graphics. But none of them seem to match what I'd expect to see for a 57x1024 microcode. Here are the sizes, in bits, of the ROMs: Bit Blit Accelerator (BBA) 23-066K3.jed 2048 23-067K3.jed 2048 23-068K3.jed 2048 23-069K3.jed 2048 23-076F4.e32 16384 23-077F4.e65 16384 23-077J5.jed 2048 23-078J5.jed 2048 23-354A1.e33 256 23-355A1.e66 256 23-356A1.e77 256 23-357A1.e85 256 Display Processor Module (DPM) 23-020L1.jed 3553 23-021L1.jed 3553 23-022L1.jed 3553 23-023L1.jed 3553 23-024L1.jed 3553 23-025L1.jed 3553 23-288E4.bin 65536 68000 code in these two. 23-289E4.bin 65536