I used Hadoop in Yahoo! to compute π,
more specifically,
the n^{th} bit of π.
A mapreduce program, called
distbbp,
was developed for such purpose.
It has been
checked in
to Hadoop 0.21 as an example program,
so that the entire program is publicly available.
The results are shown in the table on the right.

Except for the first and the last rows,
bits starting at positions n–4 and n+4 are also computed
for the sake of correctness.
 Row 0 to Row 7
 They were computed by a single machine.
 A single run of Row 7 took several seconds.
 Row 8 to Row 14
 They were computed by a 7600CPUcore cluster.
 A single run of Row 14 took 27 hours.
 The computations in Row 13 and Row 14 were completed on May 20, 2009.
It seems that the corresponding bits were never computed before.
 The first part of Row 15 (6216B06)
 The first 30% of the computation was done in idle cycles of some
clusters spread over 20 days.
 The remaining 70% was finished over a weekend on Hammer,
a 30,000CPUcore cluster, which was also used for the
petabyte sort benchmark.
 The log files are available
here.
 The result was posted in
this YDN blog.
 The second part of Row 15 (D3611)
 The starting position is 1,000,000,000,000,053, totally 20 bits.
 Two computations, at positions n and n+4, were performed.
 A single computation was divided into 14,000 jobs
and totally 7,000,000 tasks.
It took 208 years of CPUtime
or 12 days of cluster (with 7600CPUcore) time.
 The log files are available
here.
 The computations were completed on June 30, 2009.
The last bit, the 1,000,000,000,000,072^{nd} bit,
probably is the highest bit (or the least significant bit) of π
computed at that time.

 Position n  π bits (in hex) starting at n 
0  1  243F6A8885A3^{*} 
1  11  FDAA22168C23 
2  101  3707344A409 
3  1,001  574E69A458F 
4  10,001  44EC5716F2B 
5  100,001  944F7A204 
6  1,000,001  6FFFA4103 
7  10,000,001  6CFDD54E3 
8  100,000,001  A306CFA7 
9  1,000,000,001  3E08FF2B 
10  10,000,000,001  0A8BD8C0 
11  100,000,000,001  B2238C1 
12  1,000,000,000,001  0FEE563 
13  10,000,000,000,001  896DC3 
14  100,000,000,000,001  C216EC 
15  1,000,000,000,000,001  6216B06 ... D3611 
^{*}
By representing π in decimal, hexadecimal and binary, we have
π  =  3.1415926535 8979323846 2643383279 ... 
 =  3.243F6A8885 A308D31319 8A2E037073 ... 
 =  11.0010010000 1111110110 1010100010 ... 
The first ten bits of π are 0010010000.
