The following Adaptec SCSI Host Adapters are supported by the Adaptec Ultra320 OS/2 Device Driver. The Reados2.htm file lists the following devices supported:
AIC-7901, AIC-7902, ASC29320LP, ASC29320ALP, ASC39320A
The readme also states "The AICU320.ADD Ultra320 SCSI driver only supports OS/2 Warp Server for e-business."
Download: ftp://testcase.boulder.ibm.com/ps/fromibm/os2/adpu320os11.zip
Keep in mind this is on IBM's Testcase server so it is not supported by IBM unless they tell you to download it. Also items on this server only remain for 3 days or so and are then removed.
Source: OS2VOICE