Here's the only info I've ever found on the Net concerning the TAAC board:

DEVICES AND NETWORK INTERFACES          TAAC(4S)



NAME
     taac - Sun applications accelerator

CONFIG
     taac0 at vme32d32 ? csr 0x28000000

CONFIG - SUN-3/SUN-4 SYSTEMS
     device taac0 at vme32d32 1 csr 0x28000000
     device taac0 at vme32d32 2 csr 0xf8000000
     device taac0 at vme32d32 3 csr 0x28000000
     The first line should be used to generate a kernel for  Sun-
     3/160,  Sun-3/260,  Sun-4/260,  Sun-4/370 and Sun-4/460 sys-
     tems.  The second line should be used to generate  a  kernel
     for  Sun-4/110  systems; and the last line should be used to
     generate a kernel for Sun-4/330 systems.

CONFIG - SUN-4/150 SYSTEMS
     device taac0 at vme32d32 2 csr 0xf8000000

AVAILABILITY
     TAAC-1 can only be used in Sun VME-bus packages  with  4  or
     more full size (9U) slots.

DESCRIPTION
     The taac interface supports the optional TAAC-1 Applications
     Accelerator.   This  add-on  device  is  composed of a very-
     long-instruction-word computation engine,  coupled  with  an
     8MB  memory  array.  This memory area can be used as a frame
     buffer or as storage for large data sets.

     the Sun-4/150 VME address space is limited to 28 bits.   The
     TAAC-1  must  be  reconfigured to work in this package.  See
     Configuration  Procedures   fro   the   TAAC-1   Application
     Accelerator Board Set.

     Programs can be  downloaded  for  execution  on  the  TAAC-1
     directly, they can be executed by the host processor, or the
     host processor and the TAAC-1 engine can be used in combina-
     tion.   See the TAAC-1 User's Guide for detailed information
     on accessing the TAAC-1 from the  host.   This  manual  also
     describes  the  C  compiler,  the programming tools, and the
     support libraries for the TAAC-1.

     Programs on the host processor gain  access  to  the  TAAC-1
     registers and memory by using mmap(2).

SEE ALSO
     mmap(2)

     TAAC-1 Application Accelerator: User Guide
     Configuration  Procedures   for   the   TAAC-1   Application
     Accelerator Board Set



Sun Release 4.1   Last change: 6 December 1989