Data processing system and method

1. A data processing method for saving data stored within a portion of a memory associated with a first process executable by a data processing system; the data processing method comprising the steps of:

executing, using at least one of common resources,

the first process, with a respective execution priority, to perform a data processing task using a current portion of the memory; and

a backup process, having a respective execution priority, to create a back-up copy of data stored within the memory during the performance of the data processing task;

the backup process being executable in response to a predeterminable event associated with the first process;

the backup process creating a back-up copy of the data in response to the predeterminable event associated with the first process; and

installing a page fault handler associated with the memory; the page fault handler being responsive to detection of an event associated with a page to save a copy that page and then to allow a write operation to that page.

2. A data processing system for saving data stored within a portion of a memory associated with a first process; the data processing system comprising:

a processor for executing, substantially concurrently or substantially in parallel under control of a scheduler,

the first process, with a respective execution priority, to perform a data processing task using a current portion of the memory,

an installer to install a page fault handler associated with the memory; the page fault handler being responsive to detection of an event associated with a page to save a copy that page and then to allow a write operation to that page, and

a backup process, having a respective execution priority, to create a back-up copy of data stored within the memory during the performance of that data processing task;

the backup process being executable in response to a predeterminable event associated with the first process; and

the backup process creating a back-up copy of the data in response to the predeterminable event associated with the first process,

wherein the first process and the backup process are either in an execution state or a pending state, in which when the first process is in the execution state the backup process is in the pending state, and in which when the first process is in the pending state the backup process is in the execution state.

3. A system as claimed in claim 2 in which the back-up process for creating the back-up copy of the data stored within the memory comprises means for progressively traversing the memory to create a back-up copy of a respective portion of the memory; the respective portion being different to the current portion of the memory used by the first process.

4. A system as claimed in claim 2 further comprising a detector for detecting an event associated with a memory access to the current portion of the memory used by the first process and creating the back-up copy of that current portion of the memory.

5. A system as claimed in claim 4 further comprising means to change a read/write status of the current portion of memory to read-only; and in which the detector for detecting the event comprises means to detect a write attempt to the read-only current portion of memory.

6. A backup method for backing up data associated with a first process; the backup method comprising the steps of:

scheduling and executing both the first process and a first backup process according to respective execution priorities;

the first backup process comprising progressively backing-up portions of the data in a serial or sequential manner during periods of time associated with inactivity of the first process;

detecting a write operation in relation to at least one of memory or data currently being used by the first process; and

backing-up the memory or data currently being used by the first process before allowing the write operation to change the memory or data currently being used by the first process,

wherein the step of backing-up the memory or data currently being used by the first process comprises the step of responding to an exception generated by a page fault handler and backing up data of a page associated with the exception.

7. A backup method as claimed in claim 6 , wherein the first process has performed an operation to which a response is required, and wherein the backup process switches from the pending state to the execution state starting at a time when the read or write operation requested by the first process begins to retrieve data to perform the read or write operation, and wherein the backup process switches from the execution state back to the pending state when all of the data has been retrieved or written into memory for the read or write operation requested by the first process.