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 StorageTek REDWOOD TM AN OVERVIEW • SIorat3e Technolo0y Co_por,_lto,_. All Rights Reserved 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. STORAGETREKEDWOODPROPRIETARY 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 STORAGE'rERKEDWOODPROPRIETARY 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. STO_J_T REDWEOKODPROPRIETARY J 584 REDWOOD SUBSYSTEMS OVERVIEW II MEDIA O This current generation of MP media is an ideal candidate for reliable data storage. o 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. O 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_1DreR 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 Revision History 1st Draft: X3B5/91-228 14 August 1991 1st Draft: X3B5/91-229A 14 November 1991 2nd Draft: X3B5/91-466 12 February 1992 3rd Draft: X3B5/92-068 13 May 1992 REDWOOD STORAGETEKPROPRIET&RY 585 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. O Scale factor is 125X or about 2mm of the 12.65mm tape width is represented by this slide. O Bottom transitions are the longitudinal time code track, which are used for high speed searching and location verification. o Middle transition are servo sync pulse used to align the reel motors, capstan, and scanner motors for precise positioning of the tape. O 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 STORAGETREEKDWO00PROPRIETARY D3 HELICAL RECORDING FORMAT 11 cl)r III^_:R t"_;"'"1 1iLl( COIJ_ _IL^CRto*_.,,,4 STORAGETREEKDWo00PROPRIETARY J :-)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 STORAGETREEKDWOODPROPRIETARY 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 STORAGE'rREEKDWO00PROPRIETARY ] IAIILL AIILA$--._,_ \ _ / I(ADI# III_J(IL IILIAIIIIII_'_ CAnIIIIb_| IIItOIA ---/ \ , :" iU[IIIII'ICAIIOU \ 41uu llllq'Allflli It' I|AIUUf Itl[ II,H [Ikblll IIIl),il I I|1 DIGII Will I[ .I'IIUI [CI IkN[L AI[i $1.IO[ HI(flAil I$1l STORAGETREEKOWO00PROPRIETARY ] 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 STORAGETREEKDWOOPOROPRIETARY ! STK HELICAL DECK / o o STORAGETREEKDWO00PROPRIETARY J 589 o CAPACITYPERMETEROFASMUCHAS50TIMESMORE INFORMATIONTHAN3490ECARTRIDGES o DEVICEDATARATESCOMPLEMENTARYTOCAPACITY o 18MB/SCHANNELDATARATE/ESCON o 10MB/SCHANNELDATARATE/SCSIII o FIBERCHANNEL o BITERRORRATEOF10.lS I STORAGETREEKDWOODPROPRIETARY } o High speed search: 60 to 100 times Position of key records retained by for future searches o 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) STORAGETREEKDWOODPROPRIETARY J 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 STORAGETREEKDWOOP0ROPRIETARY ] 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