XENIX 2.2.3 and >1024 h.d. cylinders: possible?

[Brian Lawrence Dear]

Well, we finally got a second hard disk for our AST Premium/386 20mHz
machine.  We got a CDC WREN V, 1224 cylinders, 15 heads.  Now,
we got it up and running, and fdisk says it's got 308000 blocks, or about
317 megabytes, which is right, but the XENIX kernel or something will
only let us get at the first 1024 cylinders (indeed, if that many). 
When I do a "df -v" the drive says it has 198000 blocks total.  Or a little
over 200MB.  We need the whole thing, and we need it bad.

I can't believe version 2.2.3 can't support big hard disk drives.  I called
SCO Support today and got a suggestion that I play with DOS DEBUG and 
fiddle with the WD1007-WAH ESDI controller chip that's on AST's disk
controller card.  I said, what do I type into DEBUG, like what address, etc?
He said he didn't know.  So I am kinda stuck.

Is there anything I can do to get access to the full 317 MB of the drive, 
under SCO XENIX 386 2.2.3?  Or will I have to buy SCO UNIX?  The SCO Support
guy said that this problem "doesn't exist" on SCO UNIX (hmm...).

Has anyone encountered a similar situation?  What did you do?

If I have to upgrade, and say I upgrade to 2.3.1... would I have to delete
everything that's on the disk now, and reformat it?   I hear that version
2.3.1 supports big drives like the WREN...

Any and all suggestions are appreciated!

-- brian l. dear
   coconut computing, inc.
   7946 ivanhoe ave, suite 303
   la jolla, ca 92037