2 TByte Barrier

gop at us.ibm.com gop at us.ibm.com
Fri May 14 06:16:22 PDT 1999


* From the T10 Reflector (t10 at symbios.com), posted by:
* gop at us.ibm.com
*
If anyone doubts Jim's comments. Take a look below at the latest information
coming out of IBM Research. Yes, 2 TBytes is allot of data under one logical
unit but 10 years ago putting 1 Gbyte in one logical unit was inconceivable.

Also, IBMs current shipping version of AIX has a 64-bit kernel and SCSI disk
driver, so like it or not, 8-byte addressing is already here.


If anyone has any specific thoughts on ways they would like to see CDBs with
8-byte addressing done let me know. I will be preparing a proposal on this issue
for the July SCSI working group.

Bye for now,
George Penokie

Dept PPV  114-2 N212
E-Mail:    gop at us.ibm.com
Internal:  553-5208
External: 507-253-5208   FAX: 507-253-2880




* From the T10 Reflector (t10 at symbios.com), posted by:
* Jim McGrath <Jim.McGrath at quantum.com>
*

George has a good point.  Today we are shipping 36 GB disk drives, so you
need 60 of them to hit the 2 TB limit.  This number drops in half every time
we double drive capacity (which occurs in 12 to 18 months).  So in 2-3 years
you will hit 2 TBytes with 15 drives (one SCSI bus).  In 4-6 years (not very
long given the speed of change in system software) you will hit it with 4
drives!

Amazing how exponential growth catches up with you.

And for those of you who wonder who would every buy a 500 GB disk drive,
that is only 1 hour of megapixal uncompressed color video (or 1350 pages of
1024 dpi color pictures).  Making the drive is a bit more difficult...

Jim



IBM Sets New Disk-Drive World Record; 20 Billion Bits Per Square Inch

Business Wire, SAN JOSE, Calif., May 12, 1999 -- IBM has set a new world record
in hard-disk data-storage density, writing and reading data bits so small that
an     unprecedented 20 billion of them would fit within a square inch.

"This laboratory demonstration is very good news for our customers and the data
storage industry," said Robert Scranton, director of recording head technology
at IBM's Almaden Research Center in San Jose, Calif.

"It shows that disk-drive capacities will continue to increase well into the
21st century. This trend will enable new capabilities for portable electronics
that use IBM's tiny 1-inch microdrive or portable computers with our
industry-leading 2.5-inch drives, give desktop users rapid access to huge
multimedia files and permit large     corporations to store much more data in
the same floorspace."

The new record density of 20 gigabits per square inch (3.1 gigabits per square
centimeter) is more than three times that of any disk-drive product shipping
today. At this density, every square inch of disk space could hold 2.5 gigabytes
-- equivalent to two TV-quality movies, two hours of MPEG-2 digital video,
nearly the contents of 4 CD-ROMs or the text of some 2,500 average-sized novels.

Since 1991, when IBM introduced the industry's first magnetoresistive (MR)
sensor for reading data on hard disks, data density has increased at greater
than 60 percent a year. If that rate continues, 20-gigabit-density products
would be available within three years. Over the past eight years, the average
data-storage capacity of disk drives sold worldwide has increased more than
50-fold, while the price per gigabyte of such capacity has dropped nearly
300-fold.(a)

(a) Average disk-drive capacity in 1991: 0.145GB 1999: 7.7GB (53x)
      Average disk-drive cost/MB in 1991: $5,230/GB 1999: $18.42/GB (284x)
     (Source: Industry analyst reports)

Increasing data density can also lead to disk drives that are lighter and
consume less energy -- important factors in portable computers. In addition,
these products tend to be more reliable, because fewer disks are needed to
achieve a given data-storage capacity.

"To make smaller bits that will still store data reliably, we must improve the
disk materials and read/write components in a way that the bits can be quickly
erased and rewritten, but that their magnetic orientations will not change by
themselves," Scranton added. "The stability of the bits in this demonstration
was especially encouraging."

The 20-gigabit density milestone was achieved by a team of scientists and
engineers from IBM's Storage Systems Division, which develops, manufactures and
sells data-storage products. This demonstration is part of its long-standing
collaboration with IBM Research to understand and advance magnetic data storage
technologies.

As in its previous record-density demonstrations of 1-, 3-, 5- and 10- gigabits
per square inch (announced in December 1989, March 1995 and December 1996 and
December 1997, respectively), IBM achieved product-level reading and writing
accuracy at realistic data rates.

The 20-gigabit demonstration used an advanced version of the giant
magnetoresistive (GMR) read head -- the most sensitive sensor for reading
magnetic bits on disks -- a narrow-track thin-film inductive write head,
ultra-low-noise cobalt-alloy magnetic media and an advanced PRML
(Partial-Response, Maximum Likelihood) channel electronics. Some 490,000 bits
per inch were written along the concentric tracks packed at a density of 41,400
per radial inch.

The bits were written and read at data rates of 18 million bytes per second. The
on-track data was read essentially flawlessly, with an uncorrected rate of less
than one error in a 100 million bits, which in products would be reduced by
error-correcting codes to less than one in a trillion. The latter figure is
equivalent to transcribing more than 1,000 years of a daily newspaper before
making a single error.

The first technical details of this demonstration will be disclosed next week at
the International Magnetics Conference (Intermag 99) in Kyongju, Korea.

The IBM home page is at: http://www.ibm.com. For more information about IBM hard
drives, see http://www.ibm.com/harddrive. Details on the achievements of IBM
Research scientists can be found on the IBM Research home page:
http://www.ibm.com/research.

CONTACT:  IBM Research, San Jose
                         Michael Ross, 408/927-1283
                         mikeross at almaden.ibm.com
                         or
                         IBM Research, New York
                         914/945-4047


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