Date: Sat, 18 Nov 1995 14:56:40 -0700 (MST) From: Terry Lambert <terry@lambert.org> To: wjh@bhoss.ifx.net Cc: questions@freebsd.org Subject: Re: tape INIT ? Message-ID: <199511182156.OAA09764@phaeton.artisoft.com> In-Reply-To: <XFMail.951118144004.wjh@bhoss.ifx.net> from "Bill Henderson" at Nov 18, 95 02:40:05 pm
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> Since I have VMS exp. and not alot of UNIX exp. can anyone tell me > if there is a tape init command, I have a scsi tape drive that I am > trying to backup to and keep running out of space, it is a 2gig tape > and I know the system does not have taht much data on it, also is > there any goog backup progs. for freebsd ? Tapes in UNIX are streams of bytes that are not block addressable in most UNIX drivers. A tape is divided into logical extents sperated by EOT marks and terminated by two soft EOT marks or a physical EOT (whichever comes first). The VMS init command writes an ANSI header to a block addressable device, which subsequent backup programs read and (potentially) rewrite on a block addressable basis. Typically UNIX tapes aren't block addressable because the devices themselves aren't block addressable (ie: QIC-11/QIC-24 helical scan). This carries through to the other drivers because UNIX wants all devices to look the same. > How about some ex backup commands ? There are example commands on the following man pages: tar, cpio, dump. Dump is closest to the VMS backup utility, though it applies to full devices (unless you pick up some of the recent patches on the -hackers list to allow it to apply to subtrees). You will need to know your device name. If you are using a DAT, you may need to use the "mt" command to set the block size. People who automate backups typically use the "Amanda" system, which you can find in the "ports" collection and simply install. There is a VMS backup/restore utility capable of reading/writing VMS backup format tapes, and ANSI tapes in general. I believe it is called "vmsbackup" or "ansitape" or something like that. It is on wuarchive.wustl.edu in the comp.unix.sources archive (via FTP). Regards, Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.
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