Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!samsung!spool2.mu.edu!uunet!contex!brian
From: brian@contex.UUCP (Brian Love)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: Problems with hard drive
Summary: Problem solved (more or less).  5 partitions/287Mb
Keywords: A2000HD, A2090A, SCSI, Wren IV, prep, "Not a DOS disk"
Message-ID: <1626@contex.UUCP>
Date: 29 Jan 91 03:41:19 GMT
References: <1615@contex.UUCP> <17931@cbmvax.commodore.com>
Organization: Xyvision Design Systems, Wakefield MA
Lines: 63



I wrote about a week ago:
>I am having trouble connecting a CDC Wren IV (344Mb SCSI) hard disk to my
>A2000HD (see below for full system configuration).  

I lied in the original post.  I was able to get a single partition.  But I
don't want a single 300Mb partition (I know, bitch, bitch, bitch).  I had
settled on 5 partitions; the fifth partition going from cyl 1203 thru cyl 1400.
It would format all of partition 5, but it would fail to initialize the disk.
It wasn't the size; previous partitions worked.  It wasn't where the partition
ended; a single partition of the whole disk would work.  Therefore, I
rationalized, it must be where the partition started.  I moved the starting
cylinder of the fifth partition towards zero, and sure enough, it started
working.  My suspicion is the number of heads, blockspertrack, and cylinder are
being combined to produce an absolute block number (for the partition's start)
that is overflowing some field the driver stores in the root blocks of the
disk.  Anyway it works now.

Randell Jesup confirmed that the A2090A driver can only do 8 heads for st506
drives.  He says this has no affect on SCSI drives, but I still found it
necessary to lie to prep about the number of heads (and therefore cylinders)
on the disk.  The last partition is currently starting at cyl 953.  I'm
getting about 287M out of the disk which is good enough for me.

Again, here's my current working mountlist file (abridged):
/* MountList entries for CDC Wren IV (344 MB SCSI) Hard Disk */
RES5: Device = hddisk.device
      Unit   = 6
      Flags  = 0
      Surfaces  = 7		/* 8 would probably work here... */
      BlocksPerTrack = 46	/* NOTE: More correct value for device */
      Reserved = 2
      LowCyl = 0  ;  HighCyl = 1
      Buffers = 50
      BufMemType = 5
/* 
 This entry is present only as a reminder ... it is commented out.
DH5:  LowCyl = 2  ;  HighCyl = 2
      BufMemType = 0
*/
WR1:  Surfaces = 9
      FileSystem = l:FastFileSystem
      LowCyl = 6  ;  HighCyl = 205
      GlobVec = -1
      Mount = 1
      DosType=0x444F5301
WR2:  LowCyl = 206  ;  HighCyl = 355
WR3:  LowCyl = 356  ;  HighCyl = 505
WR4:  LowCyl = 506  ;  HighCyl = 952
WR5:  LowCyl = 953  ;  HighCyl = 1400

Thanks to everyone who replied.  It is interesting the number of replies I got
telling me the best solution was to throw the A2090A in the trash compactor and
get a "real" controller.  While I admit, I'm pretty disgusted with the quality
of the A2090A, when it works it works.  I should also point out that it is the
only controller I know of which can control both st506 and SCSI drives, which
has been a real bonus for me.

Brian C. Love

E-mail:  contex!brian@uunet.uu.net  OR  bcl@andrew.cmu.edu
Phone :  (617) 224-5578 @work       OR  (617) 395-4476 @home