From: utzoo!decvax!cca!lazear@MITRE@sri-unix
Newsgroups: net.unix-wizards
Title: Re: dump
Article-I.D.: sri-unix.1633
Posted: Sat Jun  5 22:49:21 1982
Received: Sun Jun  6 05:24:31 1982

Date: Fri, 21 May 1982 0830-EDT
The Air Force Data Services Center has done extensive work in
improving dump's capabilities:
	- it will dump at either 800 or 1600 bpi
	- it can block up to 8 Unix blocks per tape block
	- it can create identical backup tapes
	- the code is documented at least to the subroutine level
Similar work has been done with restor:
	- it will restore at 800/1600, with various blocking factors
	- it has commented code
	- it can recover from tape errors in several ways:
		- by requesting a backup tape and seeking to the
		same place on that tape and continuing (this can
		go on forever, switching tapes (much like avoiding
		potholes on a two-lane road))
		- by 'checkpointing' at each inode and losing only
		one inode in the case of no backup tape and a tape
		error (we recovered a 56000 blk filsys with 10 tape
		errors (no backup) and lost only 4 files!)
The source is available by sending a tape to:
	Charles Muir, AFDSC/CMT, Room 1D988, Pentagon, Wash, DC 20330

Walt Lazear (formerly AFDSC, now Mitre)