Copying to a NULL CD-ROM Volume Archive

COPYWRITE provides a mechanism for copying files from a source to a NULL destination.
The feature is called COPY and DISCARD, because the source data is discarded and no archive volume is created.
It is useful for verifying any source volume, including CD-ROMs created from archive volumes created by COPYWRITE.
Example 60 shows a copy and discard from a CD-ROM archive volume to NULL.
Example 61 to 63 show a copy and discard from a CD, TAPE and DISK to NULL.
When files are copied to NULL, no data transformation occurs, because after the LIBRARY/MAINTENANCE block has been received, it is discarded.
There is another form of COPY and DISCARD, in which transform action does still occur, and it uses the DUMMYFILE attribute. It is invoked by label equating a file with the same name as the the destination volume name with the DUMMYFILE attribute. When this is done, the source data is read and presented to the TRANSFORM function, however no data is written to the volume archive.For example, the SEARCH shortcut sets this attribute internally.