How to burn Fedora DVDs to avoid readahead bug?

D. Hugh Redelmeier hugh at mimosa.com
Sun Jun 3 19:59:40 UTC 2007


| From: D. Hugh Redelmeier <hugh at mimosa.com>

| 1. just because your DVD reader works this way does not mean that other
| people's DVD reader works this way.  This has been reported by several
| folks in this mailing list.

Another data point or two.

I just burned the Fedora-7-x86_64/F-7-x86_64-DVD.iso on one of my
desktops, without padding.  The system is running Fedora Core 4
x86_64.

Checking failed on the same drive that burned it.  It failed with I/O
errors at high sectors (the messages are not completely clear but they
indicate sectors very near the end but inside the written zone):
    hdc: command error: status=0x51 { DriveReady SeekComplete Error }
    hdc: command error: error=0x54 { AbortedCommand LastFailedSense=0x05 }
    ide: failed opcode was: unknown
    end_request: I/O error, dev hdc, sector 6734304
    printk: 22 messages suppressed.
    Buffer I/O error on device hdc, logical block 841788
    hdc: command error: status=0x51 { DriveReady SeekComplete Error }
    hdc: command error: error=0x54 { AbortedCommand LastFailedSense=0x05 }
    ide: failed opcode was: unknown
    end_request: I/O error, dev hdc, sector 6734312
    ...

The isosize is 3447975936 which means that there are 6734328 sectors
if you pretend that they are 512 bytes (as is to be expected, isosize
says that the actual sector size is 2048).

The drive is IDE.  hdparm says about it:
    # /sbin/hdparm -i /dev/hdc

    /dev/hdc:

     Model=HP DVD Writer 400, FwRev=KH27, SerialNo=MYHC09
     Config={ Fixed Removeable DTR<=5Mbs DTR>10Mbs nonMagnetic }
     RawCHS=0/0/0, TrkSize=0, SectSize=0, ECCbytes=0
     BuffType=unknown, BuffSize=0kB, MaxMultSect=0
     (maybe): CurCHS=0/0/0, CurSects=0, LBA=yes, LBAsects=0
     IORDY=yes, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
     PIO modes:  pio0 pio1 pio2 pio3 pio4 
     DMA modes:  mdma0 mdma1 mdma2 
     UDMA modes: udma0 udma1 *udma2 
     AdvancedPM=no
     Drive conforms to: device does not report version: 

     * signifies the current active mode

The same disk, as burned in the first drive, checks out fine when
tested in a second drive.  This drive is an external USB drive on the
same computer.  That drive is OEMed NEC that has been rebadged by Mad Dog:
  Vendor: MAD DOG   Model: MD-16XDVD9A4      Rev: 1.F2
  Type:   CD-ROM                             ANSI SCSI revision: 00

I have no idea whether the improved behaviour is due to a different
drive or using the SCSI/USB driver instead of the IDE driver.

>From past experience, I'm sure that padding would have avoided this problem.

PS: I checked using the commands:
    cmp --bytes 3447975936 Fedora-7-x86_64/F-7-x86_64-DVD.iso /dev/hdc
    cmp --bytes 3447975936 Fedora-7-x86_64/F-7-x86_64-DVD.iso /dev/scd0




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