source: liacs/os/assignment7/README@ 238

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1Student: Rick van der Zwet - 0433373
2
3> Question 1: Estimate the space to store 10^10 float numbers, using the
4> following cases, take in count to minimize the storage costs, while
5> preserving the full number accuracy.
6
7I take a float to be single precision (called float in C language) as
8the definition of float. This occupied 32 bits (4 bytes), and has got
9a significand precision of 24 bits (7 decimal digits)
10source: http://en.wikipedia.org/wiki/IEEE_754-1985
11To store integers of max 10^10, there is a need of a 64 bit integer
12(also called long)
13source: http://en.wikipedia.org/wiki/Integer_%28computer_science%29
14
15> a) We store the float numbers together with their integer index as
16> characters in a flat CSV file.
17
18Each line will look like: <index>,<float><newline>. The max numbers
19of characters of <index> will be 11, <float> will take up 7 and 1 extra
20as delimiter. Extra on every line will be 2, due to the delimiters. So 1
21line will contain 11 + 8 + 2 = 21 characters. In total 10^10 * 21. If
22you choose to use the line number as index number you will only need 8
23+1 * 10^10 characters, which is roughly (1 char = 4 bytes) 36 * 10^10
24
25> b) We store the numbers together with their index in a MySQL database.
26> Make your choice between FLOAT, DOUBLE types for the numbers and
27> SIGNED/UNSIGNED TINYINT indeces.
28
29UNSIGNED is the best choice as we are not dealing with negative
30numbers, the index is by default set in a mysql table as it it used to
31refer to the data. A FLOAT takes up 4 bytes a DOUBLE 8 bytes. So roughly
32in total it takes up (8 + 1) * 10^10 bytes. You could enlarge your FLOAT
33to gain more persision, or make it general to make sure you will only
34start loose presition after 53 digits.
35source: http://dev.mysql.com/doc/refman/5.0/en/numeric-types.html
36source: http://dev.mysql.com/doc/refman/5.0/en/storage-requirements.html
37
38> c) We store the numbers in a binary format of your own together with
39> indeces.
40
41After storing all numbers in just the simplest format as posible,
42float numbers next after eachother with a delimiter in between,would
43make it most effient.
44
45
46> Question 2: Giving the following cases, make some rough estimations the
47> time necessary to compute 10^10 association tests.
48
49Results in days,years are rounded.
50Case | each test in sec | Total/sec | Total/days | Total/years
51--------|---------------------|-----------|------------|------------
52a) | 1 | 10^10 | 115.740 | 317
53b) | 0.1 | 10^9 | 11.574 | 32
54c) | 0.01 | 10^8 | 1.157 | 3
55d) | 0.001 | 10^7 | 116 | 0
56
57> Question 3: Create a user-space envirionment for the free scientific
58> computation envirionment R.
59
60The shell script attached will create the envirionment. Commented parts
61shows what's currently going on. I have had a create help of the
62README.txt and INSTALL.txt which came with the software packages
63
64
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