To provide a multi-program processing system, which prioritizes reference and
update of a block to be an object of rollback without waiting for the rollback
being finished and can improve efficiency of processing a program when one file
is simultaneously referred to and updated by a plurality of programs. Even if the
block is being updated by another program, a file I/O section requests a journal
for the block from the journal sharing section instead of reading the block from
a data file, and transfers the contents of the block in a state before it is updated
by another program to the program if the block is being rolled back. In response
to an update request from the program, the file I/O section also refers the block
exclusion section for the state of a block as mentioned above, and if another program
does not perform neither reference nor update, the file I/O section causes the
journal collecting section to save a block before update in the journal file from
the data file as a journal, and the data file is updated.