Is CD inconsistent for different readers like floppies?
Ali...@gmail.com
read by a different machine, because of expected mechanical
differences between the machines.
So also the tolerance/settings of diffeent CDreaders is expected
to give similar problems
I normally don't use CDs, so I've just got 2 scrap CDreaders
which I plugin if I need to read a CD, which I've tried now
that a friend has posted 2 CD from the other side of the planet.
I've noticed that the one reader works well with old RH6.2
linux but not with later versions.
Also since I need to boot from the 1 CD I have to use the BIOS.
And since both my machines show differing 'errors', it suggests
that a marginal mechanical setting exists.
Do CDreaders auto adjust, so that the mechanics of different
readers is equaled out ?
== TIA.
Artem
> I've noticed that the one reader works well with old RH6.2
> linux but not with later versions.
I can suggest check IDE setting (PIO, DMA, etc) with hdparm.
>
> Also since I need to boot from the 1 CD I have to use the BIOS.
> And since both my machines show differing 'errors', it suggests
> that a marginal mechanical setting exists.
>
> Do CDreaders auto adjust, so that the mechanics of different
> readers is equaled out ?
Mechanical can not be equal. En example optical blocks can have
different mass. So, it can focusing at CD with different speed.
Try to slowdown you CD reader.
hdparm -E
And check file systems on CD. Maybe you use ext2 on CD or something
like this.
Joe Beanfish
Some readers just aren't very good at reading writable disks. And
it sometimes depends on brand and type of writable disk.
Andrew Gideon
> Some readers just aren't very good at reading writable disks. And it
> sometimes depends on brand and type of writable disk.
I've an old Sony PCG-XG29 running an old Linux (Fedora 6)
that I want to upgrade. The laptop won't boot from USB or PXE, so I
burned a DVD of Fedora 10 on another computer. No burn errors, and the
disk appears to read fine elsewhere, but the Sony cannot boot from the
DVD. It prints the first ISOLINUX line and then repeatedly makes
"grinding" noises trying to read the DVD.
I am able to mount the disk on the Sony under Fedora, but I get the same
"grinding" when I try to copy vmlinuz off of it. When I do this, I get
errors of the form:
hdc: media error (bad sector): status=0x51 { DriveReady SeekComplete Error }
hdc: media error (bad sector): error=0x30 { LastFailedSene=0x03 }
ide: failed opcode was: unknown
ATAPI device hdc:
Error: Medium error -- (Sense key=0x03)
(reserved error code) -- (asc=0x15, ascq=0x00)
The failed "read 10" packet command was:
...
Problem reading a writable disk? Is there anything I could do in writing
the disk to make success more likely, or do I have to dig up blank CDs
somewhere?
Thanks...
Andrew
Horst Franke
> I normally don't use CDs, so I've just got 2 scrap CDreaders
> which I plugin if I need to read a CD, which I've tried now
> that a friend has posted 2 CD from the other side of the planet.
Hi AliBama, be careful with used/scrap CD-Readers.
First they may be dustened (lens would need a cleanup cycle) -
next You may need specific drivers.
> I've noticed that the one reader works well with old RH6.2
> linux but not with later versions.
This looks like a driver problem (eventually firmware).
> Also since I need to boot from the 1 CD I have to use the BIOS.
> And since both my machines show differing 'errors', it suggests
> that a marginal mechanical setting exists.
Please state the failure message(s) in detail.
> Do CDreaders auto adjust, so that the mechanics of different
> readers is equaled out ?
I'm not aware of such a function.
And as the tracks are adjusted per laser I don't see any external need.
I Think You have a driver problem.
Horst
Horst Franke
> the disk appears to read fine elsewhere, but the Sony cannot boot
> from the
> DVD. It prints the first ISOLINUX line and then repeatedly makes
> "grinding" noises trying to read the DVD.
Hi Andrew, looks like the format of the DVD is not known?
> I am able to mount the disk on the Sony under Fedora, but I get the
> same "grinding" when I try to copy vmlinuz off of it. When I do
> this, I get errors of the form:
I don't know Fedora but it looks to me like "invalid/unreadable format".
> Problem reading a writable disk? Is there anything I could do in
> writing the disk to make success more likely, or do I have to dig up
> blank CDs somewhere?
May be a problem of incompatible driver?
Horst
Arno
> We know that floppies written by one machine can be difficult to
> read by a different machine, because of expected mechanical
> differences between the machines.
> So also the tolerance/settings of diffeent CDreaders is expected
> to give similar problems
Not really. The mechanisms are completely different. For once,
floppies are read magnetically with a coil in physical contact,
whuile CD/DVD are read with a laser. Floppies have stepper morors
and cannot do fine-control, while CD/DVD both has it and needs
it to work in the first place as the tracks are too fine and
the rotation is too imprecise.
> I normally don't use CDs, so I've just got 2 scrap CDreaders
> which I plugin if I need to read a CD, which I've tried now
> that a friend has posted 2 CD from the other side of the planet.
> I've noticed that the one reader works well with old RH6.2
> linux but not with later versions.
What interface? What kernel? What does "works not well" mean?
> Also since I need to boot from the 1 CD I have to use the BIOS.
> And since both my machines show differing 'errors', it suggests
> that a marginal mechanical setting exists.
Very unlikely. It can however be a marginal optical situation,
which typically is created by marginal disks or, more rearely,
dust in the drives. Also very old drives can have laser degradation
if used long enough or indead mechanical failure in the focussing
and adjustment mechanism.
> Do CDreaders auto adjust, so that the mechanics of different
> readers is equaled out ?
Yes.
Arno