Sorry about the delay, I have been busily testing every tape drive I can get
my hands on against your patch.
Kai Makisara wrote:
> > The problem is that this does not work with the Seagate DDS-4 drives, and
> > probably not with other Seagate DDS[234] type drives. I quote from the Seagate
> > DDS-4 technical documentation:
> >
> > "If no additional partition is to be defined or if going from a dual-partition
> > format to a single-partition format, the Page Length field must be set to 6,
> > which indicates that 6 parameter bytes follow the page length byte. If an
> > additional partition is to be defined (dual-partition), this field is set to
> > 8."
> >
> > If there is not a second partition, a length of 6 is reported by the mode
> > sense. Feeding a length of 6 back into the mode select in order to create the
> > partition obviously isn't going to work. The Seagate reports an error.
> >
> My HP C1533A returns always length 8.
I have verified, and the Seagate operates as I mention. In particular, the bit
about any page size other than 6 causing the Seagate to barf when you are
deleting the additional partition.
> This is already being done. The difference to your suggestion is that the
> OLD_DDS functionality is determined by comparing the number of partition
> size descriptors to the maximum number or partitions: if the number of
> descriptors is greater than maximum number of additional partitions, we
> have a non-OLD_DDS drive.
>
> The following patch might solve the problem with old DATs (compiles but
old-STYLE DATs. The Seagate DDS-4 is a brand new tape drive, it just happens
to use the old-style DAT partition page rather than the new-style SCSI-3
partition page.
[patch deleted]
Your way of detecting that you need the old-style DAT page definitely works
with a few more drives than mine did.
I have now tested the 6/8 patch against the following tape drives:
Seagate AIT
Ecrix VXA
Seagate DDS4
HP SureStore Dat24 (DDS3)
HP SureStore DAT 5000+ (DDS4)
It works properly on all of these. I will test it on the Exabyte Mammoth and
the Tandberg SLR-50 later today, but I have no doubt that it will work on them
too, since the Ecrix VXA supports Lots of Partitions the same way as the
Mammoth and SLR50. The Seagate AIT supports only two partitions, the same as
the HP's, and the AIT and the HP's use the new-style partition page.
> Thanks for your input to the driver development. I will be waiting with
> interest for your new test results.
So far so good. If it works with your drive and with Michel's drive, as well
as the hoard of drives that I tested it with above, it probably will work with
anything. I will now look at back-porting your changes to MKPART using your
method to the st.c in the 2.2 kernel in the least-intrusive manner possible
(i.e., fewest # of lines of code touched as possible). Probably will have a
patch sometime this weekend, though it won't be tested except on my own tape
drive at home.
--
Eric Lee Green [EMAIL PROTECTED]
Software Engineer Visit our Web page:
Enhanced Software Technologies, Inc. http://www.estinc.com/
(602) 470-1115 voice (602) 470-1116 fax
