Manufacturing a physical medium configured to store data

1. A method, said method comprising:

generating, by a processor of a computer system, a layout design of invisible information to be printed with invisible ink in a book, said invisible information comprising a Universal Resource Locator (URL) of an address of a web server at which additional information is located, said URL being encoded in a code within the invisible information, said additional information being associated with an article.

2. The method of claim 1 , wherein the method further comprises:

after said generating the layout design of invisible information, said processor determining that an extraction accuracy for extracting the invisible information from an image of the code satisfies a predetermined condition; and

is response to said determining that the extraction accuracy satisfies the predetermined condition said processor generating print data of the invisible information based on the generated layout design of invisible information.

3. The method of claim 1 , wherein the code is a square characterized by a code size equal to the length of each side of the square, wherein said generating the layout design of invisible information comprises:

determining a square space in the physical medium in which to print the code,

determining an offset that specifies the upper left corner of the square space in the physical medium; and

determining an angle of rotation of the square space in the physical medium relative to a specified direction in the physical medium.

4. The method of claim 3 , wherein said determining the square space comprises:

determining a minimum value of the code size; and

finding a blank space have a square shape characterized by a length of each side of the square shape exceeding the minimum value of the code size, wherein the square space consists of the blank space.

5. The method of claim 3 , wherein the determined angle of rotation is zero degrees.

6. The method of claim 3 , wherein the determined angle of rotation exceeds zero degrees.

7. The method of claim 1 , wherein the method further comprises:

said processor generating a layout design of visible information to be printed with visible ink in the book, said visible information comprising the article.

8. The method of claim 1 , wherein the code within the invisible information is a two-dimensional bar code.

9. A computer program product, comprising a computer readable hardware storage device having computer readable program code stored therein, said program code containing instructions executable by a processor of a computer system to implement a method, said method comprising:

generating, by the processor, a layout design of invisible information to be printed with invisible ink in a book, said invisible information comprising a Universal Resource Locator (URL) of an address of a web server at which additional information is located, said URL being encoded in a code within the invisible information, said additional information being associated with an article.

10. The computer program product of claim 9 , wherein the method further comprises:

after said generating the layout design of invisible information, said processor determining that an extraction accuracy for extracting the invisible information from an image of the code satisfies a predetermined condition; and

is response to said determining that the extraction accuracy satisfies the predetermined condition said processor generating print data of the invisible information based on the generated layout design of invisible information.

11. The computer program product of claim 9 , wherein the code is a square characterized by a code size equal to the length of each side of the square, wherein said generating the layout design of invisible information comprises:

determining a square space in the physical medium in which to print the code,

determining an offset that specifies the upper left corner of the square space in the physical medium; and

determining an angle of rotation of the square space in the physical medium relative to a specified direction in the physical medium.

12. The computer program product of claim 11 , wherein said determining the square space comprises:

determining a minimum value of the code size; and

finding a blank space have a square shape characterized by a length of each side of the square shape exceeding the minimum value of the code size, wherein the square space consists of the blank space.

13. The computer program product of claim 11 , wherein the determined angle of rotation is zero degrees.

14. The computer program product of claim 11 , wherein the determined angle of rotation exceeds zero degrees.

15. The computer program product of claim 9 , wherein the method further comprises:

said processor generating a layout design of visible information to be printed with visible ink in the book, said visible information comprising the article.

16. A computer system, comprising a processor, a memory coupled to the processor, and a computer readable hardware storage device coupled to the processor, said storage device containing program code executable by the processor via the memory to implement a method, said method comprising:

generating, by the processor, a layout design of invisible information to be printed with invisible ink in a book, said invisible information comprising a Universal Resource Locator (URL) of an address of a web server at which additional information is located, said URL being encoded in a code within the invisible information, said additional information being associated with an article.

17. The computer system of claim 16 , wherein the method further comprises:

said processor generating a layout design of visible information to be printed with visible ink in the book, said visible information comprising the article.

18. The computer system of claim 17 , wherein the method further comprises:

said processor generating print data of the visible information based on the generated layout design of visible information;

said processor generating print data of the invisible information based on the generated layout design of invisible information; and

said processor storing, on the physical medium, the generated print data of the visible information and the generated print data of the invisible information.

19. The computer system of claim 18 , wherein the method further comprises:

after said generating the layout design of invisible information, said processor determining that an extraction accuracy for extracting the invisible information from an image of the code satisfies a predetermined condition, wherein said generating print data of the invisible information is responsive to said determining that the extraction accuracy satisfies the predetermined condition.

20. The computer system of claim 19 , wherein said determining that the extraction accuracy satisfies the predetermined condition comprises:

simulating said extraction of the invisible information to calculate the extraction accuracy, wherein said simulating comprises utilizing the generated layout design of visible information and the generated layout design of invisible information; and

assessing the calculated extraction accuracy, wherein said assessing comprises ascertaining whether the calculated extraction accuracy satisfies the predetermined condition and if said ascertaining ascertains that the calculated extraction accuracy does not satisfy the predetermined condition then performing an iterative loop,

wherein each iteration of the loop comprises regenerating the layout design of invisible information followed by performing said simulating and said assessing, and

wherein said loop is terminated upon ascertaining that the calculated extraction accuracy satisfies the predetermined condition.