2 TByte Barrier

gop at us.ibm.com gop at us.ibm.com
Wed May 12 06:19:05 PDT 1999

* From the T10 Reflector (t10 at symbios.com), posted by:
* gop at us.ibm.com
The following is an announcement from Hitachi that indicates their new subsystem
supports a maximum capacity of 6 TBytes. I am sure this is only the first of
many subsystems that will exceed  the 2 TBytes capacity.  This is a problem for
SCSI because the largest LBA possible with in current block commands is a four
byte value. Assuming a block size of 512 bytes the current LBA provides only
enough addressing for 2 TBytes of information. Of course there are ways around
this; making the block size larger, chopping the subsystem into smaller logical
volumes, etc. but those are not necessarily the best solutions.

What the SCSI committee needs to do is create a set of block commands that move
us beyond 4 byte LBAs. But to do this we need to start a SBC-2 project and to do
that we need an editor.

>From IBMs point of view this is something that has been simmering in the
background for some time that is rapidly becoming a major issue that needs a
solution before someone invents a proprietary solution that no one likes but
that we will be forced to implement.

Hitachi Data Systems Announces New 36 GB And 15 GB Disk Drive Options for
Freedom Storage 7700E Subsystem

Business Wire, SANTA CLARA, Calif., May 10, 1999 -- New Drive Boosts Maximum
Subsystem Capacity to 6 TB; Contributes to Lower Cost of Operation -- Expanding
the range of choices available to customers who wish to optimize the capacity
and performance of their storage subsystems, Hitachi Data Systems today
announced two new disk drive options for its flagship subsystem, the
multi-platform Hitachi Data Systems(R) Freedom Storage(tm) 7700E.

The company will now offer 36 gigabyte (GB) and 15 GB disk drives with the
Freedom 7700E storage subsystem.

Doubling the maximum capacity of the Freedom 7700E to 6 terabytes (TB), use of
the new 36 GB disk drive enables customers to spread the controller cost over a
much larger subsystem capacity, providing a substantial reduction in the total
cost of operation.

The Freedom 7700E can be configured as a high-performance or high-capacity
solution. Using the 36-gigabyte disk drive, 7700E customers will be able to
achieve good performance at the lowest cost per byte. For applications that
require higher performance, customers can use the new 15 GB disk drive -- the
fastest commercially available drive in the world, spinning at more than 12,000
revolutions per minute -- to implement a configuration with up to 2.5 TB in a
single Freedom 7700E subsystem.

The 36 GB and 15 GB disk drives can be intermixed with the 18 GB and 6 GB disk
drive options currently offered with the Freedom 7700E. The new 36 GB and 15GB
disk drives are available immediately.

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

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