davis@blake.acs.washington.edu (Darrell Davis) (04/21/89)
I have been trying to figure out how/if I can read a tar tape created on a Sun-4onto my Iris 4D/20. After several futile attempts, I broke down and called the Geometry Hotline where I got all kinds of good information about various quarterinch tape formats, such as quick 24, quick 150 etc. I was told that the Iris could read a tape written by a Sun, but not vice versa. This is great since this is what I want to do, but the guy on the Hotline couldn't tell me exactly how to specify the "quick 24" format on my Iris so I could read the tape, the default Iris format is "quick 150". Since I haven't been able to discover the magic incantation, is there anyone who has solved this problem, or knows the answer.
jmb@patton.SGI.COM (Jim Barton) (04/21/89)
IRIS tapes are byte-swapped versus Sun tapes, which may be the root of
your problem (the drive knows what kind of tape it is; the OS doesn't).
Simplest way to deal with it is with 'dd', as in:
dd if=/dev/tape conv=swab bs=4k | tar xvf -
-- Jim Barton
Silicon Graphics Computer Systems "UNIX: Live Free Or Die!"
jmb@sgi.sgi.com, sgi!jmb@decwrl.dec.com, ...{decwrl,sun}!sgi!jmb
"I used to be disgusted, now I'm just amused."
- Elvis Costello, 'Red Shoes'
--olson@anchor.SGI.COM (Dave Olson) (04/22/89)
There is no way to specify using QIC24 format, the drive does this automatically. What may be causing you problems is that the byte order of the data coming from the drive is swapped when using the default device. This decision was made to be compatible with the 2000/3000 series which had a byte swapping controller. To use the non-swapping interface, specify the device as /dev/tapens. Alternatively you can fall back on dd and use conv=swab. Hope this solves your problem. By the way, this is documented in the manual page for both mtio(7) and tps(7). -- Dave Olson It's important to keep an open mind, but not so open that your brains fall out. -- Stephen A. Kallis, Jr.
phil@BRL.MIL (Phil Dykstra) (04/22/89)
> There is no way to specify using QIC24 format, the drive > does this automatically. This is true on the SGI's, but at least on the Sun 3's you need to specify /dev/rst8 to get QIC24 (the default /dev/rst0 gives you QIC11). I don't know if this holds on the Sun 4's or not. By using /dev/rst8 on the Sun's, and byteswapping on the SGI's, we have been able to move tapes between them. - Phil