Subject: Re: scsi controllers
To: None <,>
From: Theo Deraadt <>
List: current-users
Date: 11/30/1993 17:25:32
>I have successfully used and tested an Ultrastor 34F (VESA) SCSI
>controller on a box with 32MB.  In an email response from Julian
>(sp?), he seemed to indicate that either VESA or EISA controllers had
>no problems with DMA above 16MB (I don't know if he was referring to
>his latest code, or the -current code though).

The ultrastor 742 mail-box (there's these little messages passed back
and forth between the card and the driver) contains a 32 bit address.
If your bus is capable of passing 32 bit addresses this should work
(VESA does pass 32 bit addresses). Glad to hear it works.

A 1542-series controller will never work though. The mailbox format
specifies that only 24 bits of address be passed to the controller.
If you have a 32bit controller capable of running in XXX mode and 1542
mode, and want it to run with more than 16M of memory -- do NOT run it
in the 1542 mode.

example: the EISA bt742 can run in either bt742 mode or 1542 mode. In
bt742 mode the driver passes the controller a 32 bit address and
everything works. In 1542 mode the driver gives the controller a 24
bit address. If I want to put more than 16M of ram in my machine I
cannot run with the 1542 driver (of course, I run with the bt742