DATMAN TECHNICAL BULLETIN #016
From: Kan Yabumoto tech@datman.com
To: DATMAN user
Subject: What do you call this, DAT or DDS?
Date: 1996-05-22
====================================================================
The following article appeared in the December, 93 issue of the
Digital Data Storage (DDS) Manufacturers Group Newsletter.
====================================================
What do you call this, DAT or DDS?
====================================================
by
Bert Vermeulen
Hewlett-Packard
From the early days of introducing data storage applications for Digital
Audio Tape technology there has been confusion about what to call this
stuff. In this paper, I would like to shed some light on this issue and
hopefully provide conventions that will facilitate consistency among
industry participants.
What is DAT?
DAT stands for Digital Audio Tape. This acronym was originally established
to talk about a consumer audio recording technology based on 3.81mm
(0.15 inch) wide tape used in a helical scan recorder that is compatible
with the DAT Conference Standard, a book available from EIAJ (the
Electronic Industries Association of Japan). The term DAT should be used
in the following cases:
* When referring to the general technology. For example: "DAT recording
technology has more tracks per inch than 8mm recording technology."
* When referring to the consumer or professional audio technology
(recorders, players or media). For example: "DAT recorders cost
about the same as MiniDisc or DCC recorders, but have better sound
reproduction". Another example is: "This DAT tape will hold 120
minutes of music."
What is DDS?
DDS stands for Digital Data Storage. DDS is a data storage format that
was developed by Hewlett-Packard and Sony so that DAT drives could be
used for reliably storing computer data. DDS has a logo associated with
it (see Figure 1) which is protected as a trademark. This trademark
logo is primarily used to distinguish media that meets the environmental
and durability requirements of data storage applications and is suitable
for use in a drive which records data in the DDS format.
DDS media must meet a specification that is set out in ISO/IEC 10777
(for 60m DDS) or ISO/IEC 12247 (for 90m DDS). For use of the DDS logo
media must also be approved through a process managed by Sony. The DDS
logo can also be used on drives from manufacturers licensed by HP and
Sony that meet the specifications set out in the ISO/IEC standards
identified above. DDS-DC is a companion format with several extensions
that allow data compression to be used on DDS. There is no separate logo
for DDS-DC, and DDS-DC drives use normal DDS media. There are new logos
for DDS-2, DDS-3, and DDS-4 which are higher-capacity formats based on
DDS. These logos are shown in Figure 2. DDS-2, DDS-3, and DDS-4 media
are different from DDS media and will only work in drives that support
these new formats.
The term DDS can be used in the following cases:
* When talking about the format: "All drives using the DDS format can
interchange data with each other." Note that the word format can
be omitted: "All DDS drives can interchange data with each other."
* When talking about the media for data applications: "If you don't
use DDS media to store your data, you don't know whether you'll
ever see that data again," or "A 90-meter DDS cartridge will store
2 Gigabytes and a 60-meter DDS cartridge will store 1.3 Gigabytes".
* Note that it is possible to call something a DDS drive when talking
about its format. Manufacturers are encouraged to refer to their
data storage products as DDS.
The term DDS-DC can be used in the following case:
* When referring to a DDS drive that uses the data compression extensions.
Note, all of the DDS-DC drives available today use the DCLZ data
compression method and can therefore interchange compressed data.
Finally, the terms DDS-2, DDS-3, and DDS-4 can be used in the same way
as DDS. Generally speaking a DDS-2 drive can also read and write the
original DDS format on the original DDS tapes, so it is still appropriate
to call this a DDS drive (or DAT drive).
Other Forms of Address
During the course of the last years, we have come up with one other name:
Media Recognition System. Media Recognition System (which is protected
as a trademark, but should not be abbreviated because MRS is a trademark
owned by someone else) is an optical system for allowing a DDS drive to
distinguish consumer DAT media from DDS media. An example of usage
would be: "This DDS drive has incorporated the Media Recognition System".
In relation to DDS drives and DDS media, the Media Recognition System
also has its own logo associated with it (see Figure 3). This is a
DDS logo with four bars after it representing the recognition stripes
that distinguish a Media Recognition System tape from a tape without
these features. For use of this logo, media must be approved through
a process managed by Sony.
The term Media Recognition System can be used on DDS drives licensed
by HP and Sony. It is not appropriate to use the four bar logo in
relation to the DDS-2 and subsequent formats.
Some other terms that have been used for those technologies are:
* 4mm. This is as a way of contrasting this technology with 8mm
recording technology that is used for video and data storage
applications. It isn't incorrect to call this technology 4mm,
but one should recognize that audio compact cassettes also use
4mm, so one would technically need to say 4mm helical scan.
It is also worth noting that 8mm tape is exactly 8mm wide, while
our "4mm" media is actually 3.81mm wide.
* Data/DAT is a format that is very different from DDS and therefore
DDS drives are definitely not Data/DAT drives.
* Helical Data Storage (HDS) is a term that has been used by some
people to refer to DDS, Data/DAT and 8mm collectively. It has
largely fallen out of use.
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Footnote (by Kan Yabumoto):
DDS Manufacturers Group
Chairman: Robert Hill
Hewlett-Packard Ltd.
Computer Peripherals Bristol
Stoke Gifford, Bristol, UK
DDS Licensee (as of April 1994):
Aiwa, Alps, Conner Tape, DIC Digital, Exabyte, Fuji Photo Film,
Fujitsu Ten, Gigatape/Gigatrend, Hewlett-Packard, IOMEGA, Kao,
Longshine, Maxell, Mitsumi, M4 Data, Rexon (WangDAT/Wangtek),
Sanyo, Sony, TDK, Teac
The following name used to be listed in earlier rosters:
Alliance Technology, R-byte, Cipher, Philips
It is interesting that some big names are conspicuously absent
from the list:
3M, BASF, Dysan, Verbatim, Memorex,
We have heard and seen DDS tape drives marketed by the following
companies who have never been a member of the DDS manufacturing group:
IBM, Digital Equipment Corp, and Unisys
Kan Yabumoto of Pixelab, Inc. is responsible of the contents of this
page. The major portion of the page was reprinted from the original
DDS Manufacturing Group Newsletter.