[Info-vax] ZIP SYS$INPUT

[Wilm Boerhout]

JF Mezei mentioned  on 7-12-2009 20:32:
> VMS mail has a limit of 256 bytes per "record" when over a DECnet link.
> 
> When doing a task to task transfer from a backup on node 1 to ZIP on
> node 2, what would be the maximumj block size that decnet would support
> for each individual write ?

BACKUP will talk happily to a remote FAL using a network block size of 
127 blocks, and corresponding BACKUP /BLOCK=65024. I have seen resulting 
actual blocksizes in the remote save set of 65024, but sometimes it 
appears to be negotiated down to 16K or 32K.

When BACKUP in the current issue is started with /BLOCK=2048 (and 
corresponding SET RMS/NET=4), the remote ZIP process sees a stream of 
2048 byte blocks that backup does /CRC and /GROUP on. This structure has 
to be preserved by ZIP, so that when the saveset is extracted from the 
archive, it is still, well, a saveset. A linefeed inserted by ZIP after 
a 2048 byte block, for example, would create chaos in the saveset (and 
would explain why the BACKUP heaqder is intact in my case, but structure 
is destroyed later on). I have not researched this further though.

/Wilm