Spreadsheet Miscalculation of 30!

Today, I encountered something amusing. I was trying to calculate Factorial 30 (also written as 30!). Don't ask me why I was trying to calculate Factorial. :-).

As a refresher for some of us who may have forgot Factorials, Factorial 30 is product of all positive integers between 1 and 30 inclusive.

30! = 30 x 29 x 28 x 27 x 26 x 25 x 24 x 23 x 22 x 21 x 20 x 19 ... x 1.

With Microsoft Excel, using both PRODUCT function and manual multiplication 30 x 29 x ....

30! = 265,252,859,812,191,000,000,000,000,000,000

Same results on my MacBook with Numbers program, using both PRODUCT function and manual multiplication.

30! = 265,252,859,812,191,000,000,000,000,000,000

I got slightly different result with Google Docs Spreadsheet, using PRODUCT function

30! = 265,252,859,812,191,030,000,000,000,000,000

And, another different result with Google Docs Spreadsheet using manual multiplication

30! = 265,252,859,812,191,100,000,000,000,000,000

But actually,

30! = 265,252,859,812,191,058,636,308,480,000,000

It appears spreadsheets are rounding numbers after 15 or 16 digits.

Peril of Working in Cloud

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Any Vendor Strategy, why not?

Initially, I was going to post a comment on Chris Evan's recent post 2V or Not 2V (vendors this is). With the increasing length of the comment, I decided to turn it in to a blog post of my own. Chris succinctly covered the operational aspects and challenges of multi-vendor strategy.

The challenge is how deep do you go in your environment to have multiple vendors. Do you want to have multiple vendors for,

• only large items like storage subsystems?
  
• smaller stuff like HBAs and switches too?
  
• commodity type stuff that has little differentiation among vendors?
  
• specialized products?

Just because you have multiple vendors, doesn't necessarily gives you $ bargaining power. Bargaining power comes with the transaction volume, transaction size, transaction frequency and your value to the vendor.

At the smaller end, though you can achieve better operational efficiency by standardizing on single vendor, you don't have the volume and size for a single vendor to take you seriously. Unless by consolidating all your purchases you get the volume and size to be valuable to a vendor, why not just buy the best-of-breed solutions?

How much operational efficiency are you going to gain by buying three Clariion versus one Clariion, one 3Par and one Compellant?

At the high end, single vendor strategy hinders your ability to adopt innovation and new technologies with minimal gains in operational efficiency (remember large teams can be split among multiple vendors if needed) though you may be valuable to the vendor and get better pricing. How much operational efficiency are you going to lose by adding three 3Pars to couple of dozen AMS, you already have?

I have seen, heard and experienced enough horror stories to believe either single or multiple vendor strategy for any one organization is a right strategy. I favor Any Vendor strategy where your decisions are driven by the best solution that meets your need and not a solution from a pre-selected vendors that somewhat meets the needs.