Bosch Rexroth Rho 4.0, Описание системы

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8−2 Electric Drives
and Controls Bosch Rexroth AG RhoMotion 1070072367 / 04
File management
When a file is created, the file system attempts to store the file in contigu-
ous (sequential) blocks. This presupposes that a free contiguous me-
mory range exists that is big enough to accept the file. Where a range of
this nature does not exist, the file is saved to memory in distributed form.
The memory administration occupies a part of the available memory for
so-called organisation blocks in order to manage the data (data blocks) ,
i.e. not the whole memory storage space is available for filing net data.
Total memory = data blocks (files) + management blocks
To open files
The full name of a file must be given to open a file.
A file can be opened for reading many times (maximum 255 times). i.e.
various processes can read from the same file.
However a file can only be opened for writing once.
Closing files and backup copy
When an existing file is opened for writing, the file management system
first creates a copy of the original. This copy is only available to the pro-
cess which opened it until it is closed down. Until then the old file remains
unchanged.
After the file has been closed, the old file is removed from the directory
structure and the new file is entered. If the old file still has read-access,
e.g. through a process, then the file which has been removed remains
and is only completely discarded when it is closed through this process.
Process handling
Processes (ird files) must be located in the memory sequentially in order
to be executed.
When a process is chosen the ird file is sequentialized first. If this does
not succeed because no corresponding range is free, an error message
is produced.