[Info-vax] fixing a saveset's attributes: attachment, not ftp

[JF Mezei]

I a curious on what "blocksize" means in a Backup saveset ?

Does this have to do with the size of the "Blobs" of data that are
checksummed ? (aka: x bytes of data followed by checksum for those x
bytes). ?

I can understand the desirability of having the checksumed blobs fit in
their individual data blocks when on tape devices, and that different
tape devices may have different optimal block sizes.

But on disk savesets, couldn't backup simply fetch the first few bytes
to get the saveset attributes, including block size and then read the
raw data from the disk file to build individual blobs of the right size ?

Or is the IO done by backup done on a "record" (eg: SYS$GET intead of
SYS$READ) basis which does require the file have the correct record size
RMS attribute to feel BACKUP a full "blob" for each read ?

Aldo, when creating a disk saveset, would't the blocksize always be the
same by default ? Couldn't one just apply standard attributes to those
files when fixing them ?

(I realise that BACKUP/REPAIR makes this moot, but trying to understand
the underlying need to have proper RMS attributes for a file when backup
could just read the raw data irrespective of attributes).


You can do a $READ of 4096 bytes even if the LRL is 512 bytes, right ?