Method Of Storing Code Segements In Plural Printer Cartridges
A method of storing at least one functionally identical code segment in each of a plurality of printer cartridges, each having a memory, of a printing system is provided, in which a first memory location is determined which is different than a first memory location in at least a plurality of the other printer cartridges, and a first of the at least one code segments is stored in the memory at the determined first memory location. The different first memory locations are determined such that the code segment storage location of all the respective devices cannot be ascertained from the code segment storage location of any one of the printer cartridges.
1 . A method of storing at least one functionally identical code segment in each of a plurality of printer cartridges of a printing system, each of the printer cartridges having a memory, the method comprising, for each printer cartridge:
(a) determining a first memory location which is different than a first memory location in at least a plurality of the other printer cartridges; and
(b) storing a first of the at least one code segments in the memory at the determined first memory location;
wherein the different first memory locations are determined such that the code segment storage location of all the respective devices cannot be ascertained from the code segment storage location of any one of the printer cartridges.
2 . A method according to claim 1 , wherein at least one of the code segments in each of the printer cartridges includes an initial instruction, the initial instruction being located at an initial instruction location, the initial instruction location being the same in all the printer cartridges.
3 . A method according to claim 2 , wherein the initial instruction in each printer cartridge is indicative of the first memory location of that printer cartridge.
4 . A method according to claim 3 , wherein the initial instruction is indicative of the first memory location by including an explicit reference to the memory location.
5 . A method according to claim 4 , wherein the initial instruction is indicative of the first memory location by including an implicit reference to the memory location.
6 . A method according to claim 5 , wherein the implicit reference is a pointer to a location at which the address of the first memory location is stored.
7 . A method according to claim 6 , wherein the implicit reference is a pointer to a register that holds the address of the first memory location.
8 . A method according to claim 1 , wherein step (a) includes randomly selecting the first memory location.
9 . A method according to claim 8 , wherein step (a) includes selecting the first memory location based on a stochastic process or mechanism.
10 . A method according to claim 1 , wherein step (a) includes selecting the first memory location from an existing list or sequence of memory locations.
11 . A method according to claim 1 , wherein each memory is incorporated in a quality assurance integrated circuit of each printer cartridge.
12 . A method according to claim 1 , wherein the memory is non-volatile memory.
13 . A method according to claim 1 , for storing a first bit-pattern in non-volatile memory of a printer cartridge, the method comprising:
(a) applying a one way function to a second bit-pattern associated with the printer cartridge, thereby to generate a first result;
(b) applying a second function to the first result and the first bit-pattern, thereby to generate a second result; and
(c) storing the second result in the memory, thereby indirectly storing the first bit-pattern.
14 . A method according to claim 1 , for storing a bit-pattern in each of a plurality of printer cartridges, each of the printer cartridges having a memory, the method comprising, for each printer cartridge:
(a) determining a first memory location; and
(b) storing the bit-pattern at the first memory location;
wherein the first memory locations are different in at least a plurality of the respective printer cartridges.
15 . A method according to claim 1 , for storing multiple first bit-patterns in non-volatile memory of a printer cartridge, the method comprising, for each of the first bit-patterns to be stored:
(a) applying a one way function to a third bit-pattern based on a second bit-pattern associated with the printer cartridge, thereby to generate a first result;
(b) applying a second function to the first result and the first bit-pattern, thereby to generate a second result; and
(c) storing the second result in the memory, thereby indirectly storing the first bit-pattern;
wherein the third bit-patterns used for the respective first bit-patterns are relatively unique compared to each other.
16 . A printer cartridge having a code segment stored in it in accordance with the method of claim 1 .
17 . A plurality of printer cartridges having respective code segments stored in them in accordance with the method of claim 1.