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Conference pamsrc::decmessageq

Title:	NAS Message Queuing Bus
Notice:	KITS/DOC, see 4.*; Entering QARs, see 9.1; Register in 10
Moderator:	PAMSRC::MARCUSEN

Created:	Wed Feb 27 1991
Last Modified:	Thu Jun 05 1997
Last Successful Update:	Fri Jun 06 1997
Number of topics:	2898
Total number of notes:	12363

2797.0. "DmQ use checksum on messages?" by WHOS01::ELKIND (Steve Elkind, Digital SI @WHO) Mon Mar 03 1997 10:35

    Does DmQ use any sort of a checksum on its messages?  Or does it depend
    on TCP/IP error detection recovery for data integrity?
    
    (For my own information, not customer-driven for a change).

T.R	Title	User	Date	Lines
2797.1		PAMSRC::MILLER	`Mon Mar 03 1997 13:40`	6
	DmQ for Unix/NT does not use a checksum for user messages. It does however, add data integrity checking for recoverable messages that are read from or written to disk. tm
2797.2	not really necessary	CLASS7::SKELDING	`Mon Mar 03 1997 19:35`	14
	+ The network error correction is significantly robust for us to rely on it for both TCP/IP and DECNET messaging. + The recovery system keeps enough signature data to handle incomplete writes and loss of component files. Low level I/O handles the file system integrity transparently to the I/O calls in a similar way to the way the network corrects for errors. So.. we do not have to CRC data. + DmQ Datagram protocols like SBS direct ethernet broadcasting have their own internal consistancy checks.