2.4/2.6 - ATAPI Zip problem in SCSI mode (DEVFS)
Quoted 11 lines
The problem is that when having Linux booted and placing a Zip disk into the drive then mounting doesn't work. It tells me that the device doesn't exist. But the drive was found during boot
So far so good on early 2.4 you simply cd into
/dev/scsi.../.../made an 'ls' and voila it gave the device a kick and it created the entry for the Zip disk you then can mount it (devfs).For 2.5 this doesn't work anymore and whenever you want to mount a Zip disk you need to boot Linux together with a Disk inside the Drive, so during boot it detects the Zip drive + the Disk.
yes devfs was castrated in 2.6 and removable media revalidation has been removed without providing any suitable replacement.
If you use devfsd and uncomment these lines in devfsd.conf
# If you have removable media and want to force media revalidation when looking
# up new or old compatibility names, uncomment the following lines # SCSI NEWCOMPAT /dev/sd/* names LOOKUP ^(sd/c[0-9]+b[0-9]+t[0-9]+u[0-9]+)p[0-9]+$ EXECUTE /bin/dd if=$mntpnt/\1 of=/dev/null count=1 # SCSI OLDCOMPAT /dev/sd?? names LOOKUP ^(sd[a-z]+)[0-9]+$ EXECUTE /bin/dd if=$mntpnt/\1 of=/dev/null count=1 # IDE NEWCOMPAT /dev/ide/hd/* names LOOKUP ^(ide/hd/c[0-9]+b[0-9]+t[0-9]+u[0-9]+)p[0-9]+$ EXECUTE /bin/dd if=$mntpnt/\1 of=/dev/null count=1 # IDE OLDCOMPAT /dev/hd?? names LOOKUP ^(hd[a-z])[0-9]+$ EXECUTE /bin/dd if=$mntpnt/\1 of=/dev/null count=1
devfsd will attempt media revalidation on access to /dev/sdaN; if you are using canonical devfs names you may add something similar to the above, e.g.
LOOKUP (scsi/.*)/part[0-9]+ EXECUTE /bin/dd if=$mntpnt/$1/disc of=/dev/null count=1
this should revalidate media on access to partition. But you won't get partition list on simple ls as in 2.4.
-andrey
Quoted 6 lines · Andrey Borzenkov
Quoted 3 lines
For 2.5 this doesn't work anymore and whenever you want to mount a Zip disk you need to boot Linux together with a Disk inside the Drive, so during boot it detects the Zip drive + the Disk.
yes devfs was castrated in 2.6 and removable media revalidation has been removed without providing any suitable replacement.
Ahh, thanks for letting me know this.
But this leads to the question why CD-ROM removable media revalidation works. I mean let's see an SCSI CD-ROM, an ATAPI CD-ROM (in SCSI mode) and ATAPI Zip (in SCSI mode) as *the same*.
They all have a host device (the mechanics itself), they all talk through the same interface (straight SCSI or SCSI emulation). But CD-ROM removable media revalidation works. E.g. I plug a CD in and it does the trick, the Zip should be alike in my opinion. How does a Zip as removable media differ from a CD for example.
By the way it would be pretty nice to improve devfs in this case. I also heard a while back that it will be re-written anyways. Would be cool to have a native support for that (Kernel related solution).
greetings,
A. A.
Quoted 5 lines · Ali Akcaagac
Quoted 4 lines · Andrey Borzenkov
Quoted 3 lines
For 2.5 this doesn't work anymore and whenever you want to mount a Zip disk you need to boot Linux together with a Disk inside the Drive, so during boot it detects the Zip drive + the Disk.
Quoted 9 lines
Quoted 2 lines
yes devfs was castrated in 2.6 and removable media revalidation has been removed without providing any suitable replacement.
Ahh, thanks for letting me know this.
But this leads to the question why CD-ROM removable media revalidation works. I mean let's see an SCSI CD-ROM, an ATAPI CD-ROM (in SCSI mode) and ATAPI Zip (in SCSI mode) as *the same*.
CD-ROM is not partitioned device, Zip is. You always have handle for the whole disk (/dev/scsi/.../disc) - if not please let me know it is a bug. But partitions are registered only when something is forcing media revalidation i.e. attempts to access device. Just listing the devfs directory does not count as access now.
Quoted 10 lines
They all have a host device (the mechanics itself), they all talk through the same interface (straight SCSI or SCSI emulation). But CD-ROM removable media revalidation works. E.g. I plug a CD in and it does the trick, the Zip should be alike in my opinion. How does a Zip as removable media differ from a CD for example.
By the way it would be pretty nice to improve devfs in this case. I also heard a while back that it will be re-written anyways. Would be cool to have a native support for that (Kernel related solution).
well ... it was not me who removed this code ...