SUMMARY: (Addendum) DDS-2 Tape Drives on SPARCstation-5 with SunOS 5.5

Srinivas Maddhi (
Tue, 17 Feb 1998 16:57:44 -0600

On 16 Feb 1998 20:17:58 -0600 Srinivas Maddhi <>

> On 29 Jan 1998 21:46:42 -0600 Srinivas Maddhi <>
> wrote:
> > I need help determining if it is feasible to go from an existing
> > Python 4mm DDS-1 tape drive to a DDS-2 tape drive on the hardware and
> > OS combination: SunOS foo 5.5 Generic sun4m sparc SUNW,SPARCstation-5.
> We chose the HP C1599A mechanism.
> I was able to get approximately 1100 KB/s of throughput with the either
> of the two DIP switch settings mentioned above when the drive was
> connected to the second SCSI bus on an SS5 as the sole device on that
> bus.

These transfer rates were obtained using the compression device
(/dev/rmt/0c*). I was able to pack close to 7 GB onto the tape.

Transfer rates between 500 to 700 KB/s were obtained when not using the
compression device.

> Connecting it to an SS5 with only one SCSI bus and having four other
> devices attached to that bus drops the transfer rate to ~ 700 KB/s.

In this case it doesn't seem to matter what device I use -- I get
approximately the same transfer rates and capacity using any of
"/dev/rmt/{0,0m,0c}" (strange). Am able to pack approximately 6 GB to
tape (strange).

The transfer rates are as reported by 'ufsdump' (I probably should hand
check these). The capacities reported are also the result of dumping
filesystems to tape using 'ufsdump'.

Srinivas Maddhi
CCAD Computing Services