Date:   September 14, 1992                  Document:  X3T9.2/92-164   Rev 1

To:     ANSI X3T9.2 Committee (SCSI)

From:   Jeffrey L. Williams (HP)
        Steve Krupa (HP)

Subject: Request for Addition of New Density Codes


 The DDS Manufacturers Group has recently published its plans for
 further development of DDS technology over the next 3 generations.
 The details are :

     Code    Track Pitch        Linear Density
     DDS-2   9.1 micron         61000 bpi
     DDS-3   9.1 micron         97000 bpi
     DDS-4   6.8 micron         97000 bpi

 All are helical scan 3.81mm wide tape cartridges.

 The reference for the first of these is document DDS-10, but this is
 expected to be superseded by an ECMA TC17 document in September. The
 reference for the other two is X3B5/92-224.

 On behalf of the DDS Manufacturers Group, HP requests X3T9.2 to
 allocate three consecutive density codes for these generations.

 We would suggest adding the following lines to Table 198 for SCSI-3.


 Code  Width mm (in)  Tracks  Density bpmm (bpi)  Code   Type  Reference   Note
 ----  -------------  ------  ------------------  -----  ----  ---------   ----
  24H   3.81 (0.15)     1         2400 (61000)    DDS-2   C    ECMA TC17    5
  25H   3.81 (0.15)     1         3816 (97000)    DDS-3   C    X3B5/92-224  5
  26H   3.81 (0.15)     1         3816 (97000)    DDS-4   C    X3B5/92-224  5

























								Page 1