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Thread: Bigger tapes in a small drive

  1. #1
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    Default Bigger tapes in a small drive

    For three years now I have been fighting to get my trusty old Silicon Graphics 4D/20 (this is the first unix/networked/3D workstation I ever saw at the age of only four and I still vividly remember it) back to life after a failed IP6 processor board and then a disk crash where I partially lost the volume header (The geometry and partition data was there as is everything else on the drive but the bad block count in the header is too big and I can't stuff the required files back in the header). Now I have the system working under life support (It netboots to a standalone shell before I make it boot from unix off the hard drive) and today I wanted to make a tape backup. The tape drive in ti accepts 150MB QIC tapes and all I have are 320MB tapes. I tried them anyways ad the backup finished error-free. My question however is how intact is the data on the tape? Will I be able to recover off the tapes (It took four tapes to do the whole drive) or will the fact that I used a tape bigger than the drive was designed for cause issues?

    One other thing is if anyone here has ever heard or used GeoCAD? My dad used it but he can't remember what you had to do to load the database file (and thus your work).
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  2. #2
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    No idea on the tapes, did you record and verify when done? If the verify worked then it is probably ok. Most QIC tapes vary by tape length, density of recording, compression. Since newer drives tend to read older tapes they cannot be that far off from each other.
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  3. #3
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    I'm not up to par with my Unix yet so I never figured out how to verify it so I'm just going off the fact that I had no errors at all and I ran the same backup three times in a row with the same results.
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  4. #4

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    "On the 320/525 tape drive, the QIC-150 mode is used to force QIC-150 format when writing on high density media so that the tape can be read on 150/250 type drives. If a 6150 or 6250 tape media is used, the drive writes QIC-150 format in the auto-density mode."

    From that I would assume you should have no problems using 320 in 150 drives. I've done it before in the past, but it was only temporary storage not for prolonged storage.

    -Matt

  5. #5
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    3M used to put a note in their DC6250 media not to use them in drives that take DC6150/DC600XL tapes. I happily ignored it for years and still can read the 250MB tapes almost 20 years later in the same Tandberg QIC drives.

    Don't know if that helps or not.

  6. #6
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    Thanks chuck.
    Now I need to struggle to find a full height 1GB scsi disk drive to replace this one and I'll be cooking with gas again.
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  7. #7
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    Looks like it does actually work.
    I generated a bootable tape while in Irix and the PROM had no trouble loading off the tape and getting me into a miniroot.
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  8. #8

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    Quote Originally Posted by NeXT View Post
    Thanks chuck.
    Now I need to struggle to find a full height 1GB scsi disk drive to replace this one and I'll be cooking with gas again.

    Why is that? Wouldn't a more modern scsi disk with a pin-adaptor work? Or do you want it authentic?
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  9. #9
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    Quote Originally Posted by pontus View Post
    Why is that? Wouldn't a more modern scsi disk with a pin-adaptor work? Or do you want it authentic?
    The drive bracket is this thing is designed for full height drives and not half or quarter height and I'm all out of adapter rails so I can't fit in it a smaller drive.

    Also, the full height drives might not of been fast but they sounded awesome.
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  10. #10
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    full height 5.25 or 3.5...

    i have a 3gb full height 5.25 and a 2gb full height 3.5

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