Run_II_Tapes_Jan

Tape Technology for Run II

D. Amidei

Jan 2000

There is a Committee to consider this:

"The Serial Media Working Group"

D. Amidei, M. Diesburg co-chairs
J. Bakken, D. Benjamin, B. Blumenfeld,
K. Chadwick, G. Cooper, S. Fuess, K. Genser,
S. Lammel, L. Lueking, J. Patrick, D. Petravick,
D. Schamberger, H. Schellman, R. Thies, A.Walters

Where we left off:

General purpose robot allows (almost) any tape product

Waiting out the market place for next generation technologies which promise substantial gains in capacity & cost effectiveness

Focussed on commodity options with good roadmaps
       SONY Advanced Intelligent Tape:

        AIT-1 25GB 3MB/s

        AIT-2 50GB 6MB/s shipping "now"

                                      $3500/drive, $100/tape

        AIT-3 100GB 12MB/s "2001"

     EXABYTE Mammoth

        M-1 20GB 3MB/s

        M-2 60GB 12MB/s shipping "now"

                                        $4,500/drive, $80/tape

        M-3 120GB 18MB/s "2001"

Trade-off against "data center" options and other possible emerging technologies discussed in CDF-4560, Mar 98

SMWG Activities

1/19/99 Quantun DLT Site visit

1/20/99 Writeups of previous round of tests of DLT, Mammoth-1, AIT-1.
             (S. Lammel, CDF-4856, 4857, 4858)

2/17/99 Begin new program of tape drive tests with Mammoth-1,
             AIT-1, and DLT on ADIC robot. K. Genser supervising.

2/23/99 Exabyte Site visit (DA,SL,MD,KG)

3/5/99 List of performance and reliability questions sent to
            Exabyte (re Mammoth-2) and Sony (re AIT-2)

3/12/99 Exabyte team @ FNAL, inc Jorgen Frandsen, Dir. Eng.

3/31/99 Receive replies to questions from Exabyte

4/21/99 Exabyte transmits Mammoth-2 product schedule ("General availability 9/28/99")

5/5/99 Report from EMASS test program
           Reappraisal of Ampex option (L. Lueking, see end)
           Sense of committee: Mammoth "best", but keep options open

5/11/99 Initiate P.O. for 3 AIT-2. Media limit! 2 50G tape/drive

8/25/99 Rumor: Sony fails to improve 50G AIT-2 media yields

8/29/99 Second Exabyte Site Visit Mammoth-2 Test Drives

Fall 99 Many iterations with buggy Mammoth-2 microcode

1/5/00 Exabyte Ships First "Customer" Mammoth-2's

1/23/00 R/W full Mammoth-2 tape at FNAL

EXTENSIVE TESTING of AIT-1, M-1 (and DLT)

S. Lammel, Fall 98:

Bench tests, repeated R/W passes, load/unload

Summarized in CDF4856, 4857, 4868.

K. Genser, Spring 99:

Repeated operations in ADIC robot

Mount/skip/read/backspace/write/rewind/dismount, etc

Summarized in report to SMWG

Somewhat repeatable results:

         DLTs eventually have the tape stuck in the drive
         AITs develop hard and soft R/W errors after large
                 number of passes (12,000 in one case)
         Drive is "dirty", but cleaning light never came on

Conclusions

Performance of both AIT and Mammoth far better than 8mm
experience in Run I. In the Spring test, one of each drive still
OK after ~20,000 mounts, compare to average lifetime of 450
passes with Exabyte 8500.

OTHER KINDS OF INFORMATION

Re Media

Both AIT and Mammoth use Metal Evaporated Tape

For the 50/60G tapes (230m)

Kevlar-like substrate for AIT has
poor yields with the AME process
Comparative gentleness of Mammoth tape
path allows a different substrate with good yields in AME

Sony has 1 supplier

Exabyte has 4 suppliers

è Nerves about AIT-2 media availability

Re Exabyte:

Extremely good interactions with company

Direct line to engineers, even to Engineering Director
Us there twice, them here once
Nice reply to detailed technical questions
Continued followup, inc. non-disc. product schedule

Re Sony:

Very difficult to get a straight story from anyone

Believe we were lied to about irregularities in AIT-1 media

May 99 "SENSE OF THE COMMITTEE"

Mammoth-1 has performed acceptably in our tests, and Mammoth-2 looks promising. Mammoth-1 is back compatible with Run I tapes, and would be an acceptable starting point, with forward compatibility of new tapes to Mammoth-2.The Committee feels that Exabyte Mammoth is the best candidate at this time.However, we still have a window this summer for testing both Mammoth-2 and AIT-2, and we will.We would like to make a decision that would allow us to have of order 10 drives installed for each experiment by ca. September…

THEN WHAT:

5/11/99 Initiate P.O. for 3 AIT-2. Media limit! 2 50G tapes/drive

8/25/99 Rumor: A focussed program at Sony fails to improve 50G AIT-2 media yields

8/29/99 Second Exabyte Site Visit Mammoth-2 Test Drives

             i.e. general availability is delayed

Fall 99 Many iterations with buggy Mammoth-2 microcode

           AIT-2 running at FNAL. Looks OK but n.b. no stress tests.

           Comdex 99: Super DLT and LTO, expected Q4-99, are delayed

1/5/00 Exabyte Ships First "Customer" Mammoth-2's

1/12/00 Meet with ADIC representative. Learn that their 8mm install

             base is > 15,000 AIT, almost no Mammoth

1/20/00 Rumor: Sony is adding a second supplier for AIT-2 tapes

             Will "eliminate backlog" by April

1/23/00 R/W full Mammoth-2 tape at FNAL

WE COULD:

Get started with M-1, count on M-2 coming along.

Fear: Exabyte is too late with M-2, will not recapture
market, will fold, we will be stuck with data archived
with defunct technology

Get started with AIT-2, count on the giant SONY to fix their media problems

Fear: No tapes to be found as TBytes begin to flow from B0

WE NEED TO:

Make a decision soon

Probably: Take a stab at one or the other for
Spring/Summer/Commission-Run, be prepared to
revisit/retrofit in the Fall.

Re-evaluation of a Data Center Option

L. Lueking, May 99

Table I. Drive streaming throughput, media and AML2 capacities.

Mammoth II numbers assume 230m tapes.

Ampex Mammoth I Mammoth II

-------------------------------------------------------------------------------

Drive 20 3 12

(MBps)

Media 279 18 60

capacity (GB)AML2 1152 5185 5185towerslotsAML2tower 321 93 311capacity

(TB)

------------------------------------------------------------------------------

Table II. Quantity, unit price, and total costs for drives to support

200 MBps (streaming) and media to store 1 PB of data.

Mammoth II numbers assume 230m tapes.

AMPEX Mammoth I Mammoth II

Number @ Total Number @ Total Number @ Total

----------------------------------------------------------------------------------------------

Drive 10 100k 1,000k 70 2.5k 175k 20 4k 80k

Media 3584 250 896k 55,555 80 4.45M 16,666 80

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Total $1,896k $4,625k $1,413