Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!ucsd!sdcsvax!ucsdhub!hp-sdd!hplabs!hpfcdc!hpgrla!stevewy
From: stevewy@hpgrla.HP.COM (Steve Wiley)
Newsgroups: comp.sys.hp
Subject: Re: backup HP-UX systems over e-net
Message-ID: <4870002@hpgrla.HP.COM>
Date: 15 Mar 89 16:42:07 GMT
References: <263@verdix.verdix.com>
Organization: Hewlett-Packard, Greeley, CO
Lines: 32

Here's some facts about HP's RDAT product.

RDAT:
  Capacity:  1.3 GBytes  (HP/SONY DDS Format "The highest capacity format")
  Transfer Rate:  183 KBytes/Sec  (HP/SONY DDS Format "The fastest format")
  Error Rate: <10E-15 Errors/Bit
  MR Date:  Sometime this fall.
  Interfaces:  Single Ended SCSI
	       HPIB
  What is it?  The DDS format was designed to make RDAT as fast and as high
	       capacity as possible.  Competing formats are both slower and
	       lower capacity.  The product will look much like any sequential
	       tape drive to the system with a few exceptions.  One of these
	       is the creation of a new type of tape mark, the Save Set Mark.
	       This mark can be used to group files, similar to how a file mark
	       groups records.  With this mark, each client on the LAN could
	       be backed up within its own save sets.

	       One of the most interesting facts about DAT is that a record
	       boundary ("gap"), filemark, and save set mark only eat up 4
	       bytes of tape space, hense not degredation in capacity or
	       transfer rate.  Also, a DDS RDAT cartridge requires no pre-
	       formating.

	       Finally, it is possible to partition a DDS cartridge into 2
	       partitions.  This first partition (the smaller one) could
	       be used as a directory of the second partition.  This first
	       partition does require the use of a format statement.

  Concerns:  If the best the LAN can do is 50 KBytes/Sec the RDAT will 
	     reposition quite a bit.  This is not the idea case but should
	     not cause a great deal of trouble.