neese@adaptx1.UUCP (05/14/91)
>/* ---------- "Adaptec 1540B/1542B compatibility q" ---------- */ > >I am interested in purchasing an Adaptec 1540B or 1542B controller to >run DOS and UNIX (ESIX). I have been told that there are compatibility >problems with the card and Windows 3.0 and other DOS programs. > >Can someone fill me in on the actual problems? (if any) You have been misinformed. You have a couple of options in running Windows 3.0 with a bus master (AHA-1542B). You can leave SMARTDRV.SYS loaded and 3.0 will work just fine. If you don't want to use SMARTDRV.SYS you will need the ASW-1410 ASPI DOS Manager. The problem is this: A bus master needs physical addresses as it is the card that is responsible for moving the data to/from the SCSI device and host memory. Windows 3.0 puts the 386 into virtual mode and thus all memory references are no longer physical, but are logical. SMARTDRV.SYS allocates a fixed amount of memory in lower DOS RAM whose logical addresses also happen to correspond to the physical addresses. Thus, no other driver is required. The ASW-1410 ASPI DOS Manager use the INT4B services as defined by Microsoft in Windows 3.0. One of these services allows the driver to ask for a physical memory reference from the logical memory reference, thus bus masters are happy. Roy Neese Adaptec Senior SCSI Applications Engineer UUCP @ neese@adaptex uunet!cs.utexas.edu!utacfd!merch!adaptex!neese