Technical Blog Post
Abstract
The Petronas Twin Towers
Body
Continuing my business trip through Asia, I have left Chengdu, China, and am now in Kuala Lumpur, Malaysia.

On Sunday, a colleague and I went to the famous Petronas Twin Towers, which a few years ago were officially the tallestbuildings in the world. If you get there early enough in the day, and wait in line for a few hours, you can get a ticket permitting you to go up to the "Skybridge" on the 41st floor that connects the two buildings. The views are stunning, and I am glad to have done this.(If you are afraid of heights, get cured by facing your fears with skydiving)
You would think that a question as simple as "Which is the tallest building in the world?" could easily be answered, given that buildings remain fixed in one place and do not drastically shrink or get taller over time or weather conditions, and the unit of height, the "meter", is an officially accepted standard in all countries, defined as the distance traveled by light in absolute vacuum in 1/299,792,458 of a second.
The controversy stems around two key areas of dispute:
- What constitutes a building?
A building is a structure intended for continuous human occupancy, as opposed to the dozens ofradio and television broadcasting towers which measure over 600 meters in height. The Petronas Twin Towers is occupied by a variety of business tenants and would qualify as a building. Radio and Television towers are not intended for occupation, and should not be considered.
- Where do you start measuring, and where do you stop?
Since 1969, the height was generally based on a building's height from the sidewalk level of the main entrance to the architectural top of the building. The "architectural top" included towers, spires (but not antennas), masts or flagpoles. Should the measurements be only to the top to the highest inhabitable floor?
What if the building has many more floors below ground level? What if the building exists in a body of water, should sidewalk level equate to water level, and at low tide or high tide? (Laugh now, but this might happen sooner than you think!)
To bring some sanity to these comparisons, the Council on Tall Buildings and Urban Habitat has tried to standardize the terms and definitions to makecomparisons between buildings fair. Why does all this matter whose building is tallest? It matters in twoways:
- People and companies are willing to pay more to be a tenant in tall towers, affording a luxurious bird's-eyeview to impress friends, partners and clients, and so the rankings can influence purchase or leasing prices of floorspace in these buildings.
- Architects and engineers involved in building these structures want to list these on their resume.These buildings are an impressive feat of engineering, and the teams involved collaborate in a global mannerto accomplish them. If an architecture or engineeering company can build the world's tallest building, you can trust themto build one for you. The rankings can help drive revenues in generating demand for services and offerings.
What does any of this have to do with storage? Two weeks ago, IBM and the Storage Performance Councilanswered the question "Which is the fastest disk system?" with apress release. Customers thatcare about performance of their most mission critical applications are often willing to pay a premium to run theirapplications on the fastest disk system, and the IBM System Storage SAN Volume Controller, built through aglobal collaboration of architects and engineers across several countries, is (in my opinion at least) an impressive feat of storage engineering.
EMC bloggerChuck Hollis was the first to question the relevance of these results, and I failed to "turn the other cheek" and responded accordingly. The blogosphere erupted, with more opinions piled on by others, many from EMC andIBM, found in comments on these posts or other blogs, some have since been retracted or deleted, while othersremain for historical purposes.
At the heart of all this opinionated debate, lies a few areas of exploration:
- What constitutes a "disk system"? What should or should not be considered for comparison?
- What metrics should be used to measure performance? What is a version of the "meter" everyone can use?
- How should the measurements occur? Who should perform them?
- Do the measurements provide sufficient value for the purpose of aiding the purchase decision making process?
I will try to address some of these issues in a series of posts this week.
technorati tags: IBM, KL, Kuala Lumpur, Malaysia, Petronas, Twin Towers, SkyBridge, tallest, building, structure, tower, fasted, disk, system, SVC, SAN Volume Controller, EMC, Chuck Hollis, SPC, Storage Performance Council
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