Redwood is a new generation tape subsystem now under development at StorageTek using helical scan technology. This library based storage subsystem is designed for the high performance, deep archival market. The topics are presented in viewgraph form and include the following: subsystem overview, media standards, Redwood developed tape, D3 helical recording format, Redwood cartridge, host software for Redwood libraries, and market opportunities

Cheatham, Sam

English

NASA Technical Reports Server

The Redwood Project:
An Overview
Sam Cheatham
Storage Technology Corporation
Vice President
Tape and Library Systems Development
VC Technical Committee X3B5
2270 South 88th Street
MS 0275
Louisv/lle, CO 80028
581
https://ntrs.nasa.gov/search.jsp?R=19930022790 2020-03-17T05:18:42+00:00Z
StorageTek
REDWOOD TM
AN
• SIorat3e Technolo0y Co_por,_lto,_. All Rights Reserved
OVERVIEW
Slor_]eTek and Nearllne are registered trademarks o| Stm'age Tec_mology
Corporst,on RedWood is a trademark of Storage Tecltnology Corpo_'etv_n Other
feetureslproduct names mentJoi_ed are trademarks of Stocage Tech_y
Corporalton of oU'_er vondofs/inentlIac|ufers.
REDWOODSTORAGETEK PROPRIETARY
REDWOOD
O REDWOOD IS A NEW GENERATION TAPE SUBSYSTEM NOW
UNDER DEVELOPMENT AT STORAGETEK USING HELICAL
SCAN TECHNOLOGY.
o THIS LIBRARY BASED STORAGE SUBSYSTEM IS DESIGNED
=_D TU= HIP.H PI=RFORMANCE, DEEP ARCHIVAL MARKET.I _./| | i | i_ |_. • • ........ .
REDWOOD
STORAGETEK PROPRIETARY
,.= ,
583
REDWOOD SUBSYSTEM OVERVIEW
o RedWood is the outgrowth of a series of internal strategic planning
and customer advisory board meetings.
O The RedWood Project, combined with the StorageTek Library
Systems, is StorageTek's strategy in satisfying our customer
requirements.
o RedWood consists of combination of:
High-performance 36-track StorageTek tape subsystem
State-of-the-art digital video system as used in broadcast studios
I REDWOODSTORAGE'rEK PROPRIETARY
REDWOOD SUBSYSTEM OVERVIEW
o The architecture of the RedWood tape subsystem takes best
advantage of the formats and operational parameters defined for
video 'D3 ° devices.
o Capacity per meter of as much as 50 times more information than
3490E cartridges.
o State-of-the-art media formulation integral factor in deck's design.
REDWOOD JSTO_J_T E K PROPRIETARY
584
REDWOOD SUBSYSTEMS OVERVIEW II
MEDIA
O
o
O
This current generation of MP media is an ideal candidate for
reliable data storage.
Significant improvements have been achieved in durability and
stability over earlier generations.
The RedWood MP media along with its improved cartridge will meet
or exceed 3480-class media lifetimes.
MP media technology will continue to benefit from extensive R & D
expenditures in the commercial broadcasting sector and from work
now in process within the data storage sector.
REDWOOD
STORAGETEKPROPRIETARY
MEDIA STANDARDS
3_1 DreR
PROPOSED
AMERICAN NATIONAL STANDARD
HELICAL-SCAN DIGITAL COMPUTER TAPE CARTRIDGE
12.65 mm (0.50 in)
FOR INFORMATION INTERCHANGE
13 May 1992
(ASC X3 Project No. 850-D)
Prepared by
Technical Committee X3B5
of Accredited Standards Committee X3
1st Draft:
1st Draft:
2nd Draft:
3rd Draft:
Revision History
X3B5/91-228
X3B5/91-229A
X3B5/91-466
X3B5/92-068
REDWOOD
STORAGETEKPROPRIET&RY
585
14 August 1991
14 November 1991
12 February 1992
13 May 1992
OO
O
o
O
Using a ferromagnetic fluid, the magnetic domains of a recorded tape
can be viewed under magnification to show track alignment,
transition spacing, defects, and data format.
Scale factor is 125X or about 2mm of the 12.65mm tape width is
represented by this slide.
Bottom transitions are the longitudinal time code track, which are
used for high speed searching and location verification.
Middle transition are servo sync pulse used to align the reel motors,
capstan, and scanner motors for precise positioning of the tape.
Helical tracks in the upper area are written at opposing 20 ° azimuth
angles to reduce cross talk and allow gapless recording. The tracks
are written at an helix angle of 4.92 ° with a track spacing of 20 uM
(1270 TPI).
I REDWO00STORAGETEK PROPRIETARY
D3 HELICAL RECORDING FORMAT 11
cl)r III^_:R t" _;"'"1
1iLl( COIJ_ _IL^CR to *_.,,,4
REDWo00 JSTORAGETEK PROPRIETARY
:-)86
REDWOOD CARTRIDGE II
o Same media as D3 with video format extended for data.
o Storage reel only - permanent take-up reel; in drive.
o Packaged in a 3480 form-factor cartridge.
o Accommodates same range of tape length as 3480.
o Meets or exceeds 3480-class media lifetimes.
o ANSI format includes data compression.
REDWOOD
STORAGETEK PROPRIETARY
REDWOOD CARTRIDGE FEATURES
o Tape pulled from opposite corner to 3480
- Straighter path for loading arm
o Improved leader block design over 3480
Field-replaceable without special tools
- More reliable latching mechanism
o Notch to ensure no damage if inserted into 3480 drive
O Design ensures no damage if 3480 cartridge inserted in helical
scan device
REDWOODSTORAGETEK PROPRIETARY
587
I REDWOOD CARTRIDGE FEATURES /
o Improved write-protect switch, length and machine type recognition
scheme
Separate cartridge/media identification block for ease of
manufacturing
o Same label areas as 3480 cartridge
Additional area on trailing-edge
I REDWO00 ]STORAGE'rEK PROPRIETARY
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REOWO00 ]STORAGETEK PROPRIETARY
588
REDWOOD SUBSYSTEM OVERVIEW
o Head and tape wear characteristics differ from linear tape devices
since the relative head-to-tape speed for RedWood is quite high,
on the order of 1000 ips, in support of available data rates.
o Life expectations for media and heads will far exceed those
currently thought possible in all modes of use.
o StorageTek has defined a means to keep track of customer tape
and head usage facilitating preventive maintenance, timeliness
and convenience to the customer.
I REDWOOOSTORAGETEK PROPRIETARY
! STK HELICAL DECK /
o
o
REDWO00 JSTORAGETEK PROPRIETARY
589
o CAPACITYPERMETEROFAS MUCHAS 50TIMES MORE
INFORMATIONTHAN3490ECARTRIDGES
o DEVICEDATA RATESCOMPLEMENTARYTO CAPACITY
o 18MB/SCHANNELDATA RATE/ESCON
o 10MB/SCHANNELDATA RATE/SCSIII
o FIBERCHANNEL
o BIT ERRORRATE OF10 .lS
I REDWOOD }STORAGETEK PROPRIETARY
o
o
High speed search: 60 to 100 times
Position of key records retained by for future searches
File Safd"
- Allows tape to be written once and only once
- Information can be appended, but existing records cannot be
overwritten
- Emulates optical Write Once Read Mostly (WORM)
REDWOOD JSTORAGETEK PROPRIETARY
590
o Higher device data rate requires fresh approach
- Original ESCON announcement by IBM barely fast enough
- Need ESCON performing at limit (approx. 18 megabytes/s)
o Given the push towards open-systems and standards
New versions of SCSI (SCSI-2 fast and wide) will see use for
workstation market with RedWood
HIPPI established in supercomputer systems, and thus is
addressed in RedWood architecture
Fiber Channel expected to become interface of choice for
medium and high-performance RedWood systems users
I REDWOO0 ]STORAGETEK PROPRIETARY
I HELICAL VERSUS LONGITUDINAL II
o Helical has longer mechanical latencies
Not a problem - uses large buffers
Very short records may lead to non-optimal performance and
capacity utilization
o Helical has lower inherent BER than longitudinal
Add 3rd Level ECC to achieve 10 ""
Both 3rd Level ECC and write retry can be disabled by system
REOWOO0
STORAGETEK PROPRIET&RY
591
o All RedWood products will operate in a library environment. The
architecture also allows the customer to use stand-alone drives
with or without stacker-loaders.
o All StorageTek libraries are capable of storage and management of
the new helical scan cartridge.
o General availability features will include mixed media in the
StorageTek library family (both helical and 3480 type media).
I REDWOOO ISTORAGETEK PROPRIETARY
LIBRARY
Estimated Floor space (sq ft)
3490E (36track) Capacity
RedWood I (terabytes)
TIMBERWOLF
23
10
WOLFCREEK
33
20
4400/PH
100
120
o Capacity comparison does not include compression
o Floor space does not include access for manual loading, servicing
REDWOODSTORAGETEK PROPRIETARY
592
HOST SOFTWARE FOR
REDWOOD LIBRARIES i
o IBM ARENA
MIXED MEDIA SUPPORT AT GA
o OPEN SYSTEMS
CUSTOMER REQUIREMENTS WILL BE USED TO REFINE
HOST SOFTWARE AND DEVICE CONNECTIVITY FOR
EACH SPECIFIC CASE.
I REDWOO0STOR&GETEK PROPRIETARY
PRODUCT EMPHASIS
IBM ARENA
OPEN SYSTEMS
FEDERAL AGENCIES
MID RANGE PRODUCTS
I REDWOOD ISTORAGETEK PROPRIETARY
59,3
MARKET OPPORTUNITIES
o Continued steep growth in capacity requirements
o Driven by new applications
Imaging, seismic
High-definition full-color video stored digitally
Archives formerly on fiche, etc.
o Only 1% of business data stored in digital form in 1990, growing to
3-5% by year 2000 (source AIM report)
- Every company will have a true "mass storage" problem as
percentage grows
REDWOODSTORAGETEK PROPRIETARY
I PRODUCT AVAILABILITY In
1994
I REDWOOD t$TORAGETEK PROPRIETARY
594
[ TAPE SUBSYSTEM PRICE TRENDS
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REDWOO0
STORAGETEK PROPRIETARY
T
H
O
U
S
A
H
D
S
SETS OF
ENCYCLOPEDIAS
ISO0 -i
500 _
0
I REDWOOD POTENTIAL IN A 4400 LIBRARY "_
IN SETS OF ENCYCLOPEDIAS
CAPACITY OF A SINGLE 4400 SILO
1,S
MILLION
lS 30
THOUSAND THOUSAND
80 120
THOUSAND THOUSAND
200 MB COMPRESSION 36 TRACKS LONGER TAPE
2:1
HELICAL
NO COMPRESSION
SILO CAPACITY PER CARTRIDGE CAPACITY
REDWOOD ]STORAGETEK PROPRIETARY
SETS OF
ENCYCLOPEDIAS
250
200
150
100
50
0
200 MB
CARTRIDGE CAPACITIES IN SETS OF _1
ENCYCLOPEDIAS I
CAPACITY OF A SINGLE CARTRIDGE
20
COMPRESSION
2:1
X TRACKS
CARTRIDGE PARAMETER
I tiE.WOODSTORAGETEK PflOPRIE'rAflY
LONGER TAPE HELICAL
NO COMPRESSION
SUMMARY
O RedWood allows investment in current-generation Nearline
technology to be preserved in defining next-generation
mass-storage systems.
o Helical scan technology offers order-of-magnitude improvement in
capacity and density, cost/GB for all Libraries.
o Use of existing broadcast technology in RedWood significantly
lowers risk.
Extensive R&D expenditures in the commercial broadcast
sector will facilitate future generations of StorageTek helical-
scan products
I REDWOoOSTORAGETEK PROPRIETARY
596
SUMMARY
o Proposed standards-based helical-scan cartridge
- Allows existing Nearline products to be upgraded by mixing new
media with the existing cartridge set
- Provides improvement in data rate over existing Nearline products
in archival applications
o New helical-scan features, e.g., high-speed search, File Safe will be
application enablers.
o RedWood facilitates use of Nearline technology in next generation
mass-storage systems.
I REOWOO0STORAGETEK PROPRIETARY
597


The redwood project: An overview

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