jtalley@magnus.acs.ohio-state.edu (James T Talley) (06/12/91)
To add to the discussion on tape backup for A/UX systems, I have some information and a question. Someone mentioned that they were considering purchasing an FWB hammerTape because it at least claimed to work with A/UX. As someone that has used the hammerTape250 from FWB for about a week with our A/UX system, I can verify that it seems to function as advertised. I've used pax, cpio, dd, and dump.bsd with it and am able to reliably read and write the tape. With one minor exception (see below) I'm quite happy with it. (If you want more info, let me know.) My question has to do with writing multiple files to a single archive tape. The FWB software lets you address the drive as '/dev/rmt/tc4' or '/dev/rmt/tc4n' where 4 is the SCSI ID of the drive and the 'n' means do *not* rewind when done reading or writing. Thus the 'n' version of the device lets you write multiple files to one tape cartridge. I'm using the '/dev/rmt/tc4n' device to archive large transient files that arrive on my system each night via UUCP. My problem is that it seems that you have to make all the writes in one pass. As long as I only make writes to '/dev/rmt/tc4n' device, I can continue writing files to a single cartridge. As soon as I use the 'mt' command to reposition the tape, I start to get write errors and can no longer write more files at the end of the tape. If I rewind and start over, I can start making multiple writes again. This means I can continue using the cartridge to store more data as long as I don't try to access the data that's already on the tape. Any other access seems to make it read-only until I rewind and re-use the whole tape. I can live with this, if necessary. Is this normal? Am I missing something obvious? The man page for 'mt' is not very helpful in this regard. Any help is appreciated. James T. Talley
tony@kahu.marcam.dsir.govt.nz (Tony Cooper) (06/12/91)
In article <1991Jun11.205058.799@magnus.acs.ohio-state.edu>, jtalley@magnus.acs.ohio-state.edu (James T Talley) writes: |> I'm using the '/dev/rmt/tc4n' device to archive large transient files |> that arrive on my system each night via UUCP. My problem is that it |> seems that you have to make all the writes in one pass. As long as I |> only make writes to '/dev/rmt/tc4n' device, I can continue writing |> files to a single cartridge. As soon as I use the 'mt' command to |> reposition the tape, I start to get write errors and can no longer |> write more files at the end of the tape. If I rewind and start over, |> I can start making multiple writes again. |> |> This means I can continue using the cartridge to store more data as |> long as I don't try to access the data that's already on the tape. |> Any other access seems to make it read-only until I rewind and re-use |> the whole tape. I can live with this, if necessary. I don't know what the FWB250 drive is but lots of drives let you write data at the end of the tape and nowhere else. Where else would you want to write it anyway? The only other place is in the middle and that means the rest of the tape gets trashed. Some drives let you trash the tape this way, others don't. My tape drive tutorial (on jagubox.gsfl.nasa.gov) explains all this kind of stuff. My st tape drive is smarter than the FWB one (skite, boast). It won't produce write errors when you try to do the writes. It prints a nice English error message telling you what you are doing wrong. Cheers, Tony Cooper
hase@netmbx.UUCP (Hartmut Semken) (06/17/91)
jtalley@magnus.acs.ohio-state.edu (James T Talley) writes: >I'm using the '/dev/rmt/tc4n' device to archive large transient files >that arrive on my system each night via UUCP. My problem is that it >seems that you have to make all the writes in one pass. As long as I >only make writes to '/dev/rmt/tc4n' device, I can continue writing >files to a single cartridge. As soon as I use the 'mt' command to >reposition the tape, I start to get write errors and can no longer >write more files at the end of the tape. If I rewind and start over, >I can start making multiple writes again. I am having the same problem, but I used Tony Coopers st tape driver with a Tandberg TDC3640 tape. When trying to position the tape (using "tape" by Tony Cooper or mt) and then writing, I get a message like "illeagal operation attempted". First, I suspeckted the tape drive, but then, it works with FastBack II under MacOS... hase -- Hartmut Semken, Lupsteiner Weg 67, 1000 Berlin 37 hase@netmbx.UUCP Hi! (Zaphod Beeblebrox)