A record or a record in a file is a group of data elements treated as an entity by READ and WRITE statements in programs. A block is a group of one or more records that the logical I/O subsystem transmits to and from I/O units. Files are often structured with multirecord blocks to increase the overall speed of I/O data transfers and to increase the amount of data that can be stored in a given amount of disk or tape space.
DUMPALL reads and writes data records from and to files one record at a time. DUMPALL uses the ordinary logical I/O subsystem of the ClearPath MCP operating system to read and write files. DUMPALL does not simply read and write bulk masses of data as the library maintenance utility does.
For these reasons, DUMPALL needs to know the organization and structures of the input and output files, and the size of each data record and block of data records in the files. Some files, such as printer backup disk files, have special structures that the DUMPALL utility cannot copy properly. But most files on ClearPath MCP systems are structured with file attributes that logical I/O supports. DUMPALL can correctly copy and print those kinds of files.
The keys to the success of printing and copying files with DUMPALL are as follows:
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Make sure that DUMPALL uses the correct values for MAXRECSIZE and BLOCKSIZE when it reads the input files.
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Make sure that data translation does not occur unless you want it to.
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In the case of an unlabeled tape input file or a nonstandard labeled input file, use the SKIPTM option to correctly position the input tape to the area of the tape that contains the data records of the input file you want to copy or print.
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In the case of multifile input or output tape files, use the MULTIFILE option correctly.
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When you copy a file that has fixed-length records and you have not specified that the output file should have variable-length records, the output file does not assume a nonzero MINRECSIZE value for the input file.
DUMPALL might be able to process tape files written on other operating systems. Success depends on the following factors:
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The files must be structured in a manner that the logical I/O subsystem supports.
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You must specify the proper values for record size and other file attributes in the commands that you give to DUMPALL.
