* Re: blocksize 4096 even for floppy and CDROM?
[not found] <e4ab39cb-fbe7-1148-8d8a-5cd46866159f@gmx.net>
@ 2022-02-22 23:24 ` Randy Dunlap
2022-02-23 4:00 ` Martin K. Petersen
0 siblings, 1 reply; 3+ messages in thread
From: Randy Dunlap @ 2022-02-22 23:24 UTC (permalink / raw)
To: JPT, linux-kernel, linux-block
[adding the linux-block mailing list]
On 2/22/22 12:08, JPT wrote:
> Hi,
>
> sorry for bothering. I fear I need help by a block device pro ;)
>
> I try to read several bad floppies and DVDs using safecopy.
>
> I wonder why safecopy always says
> Reported hw blocksize: 4096
> Reported low level blocksize: 4096
>
> even if the medium is floppy (512) or CDROM (2048)
>
> is this a kernel issue always assuming min 4k block size?
>
> Does anybody have an idea if there is a Unix out there that doesn't have
> this limitation?
>
> or which Linux version dropped support for smaller sectors?
>
> Or is this simply safecopy's fault?
>
>
> thank you very much for your help.
>
> Jan
--
~Randy
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: blocksize 4096 even for floppy and CDROM?
2022-02-22 23:24 ` blocksize 4096 even for floppy and CDROM? Randy Dunlap
@ 2022-02-23 4:00 ` Martin K. Petersen
2022-02-27 11:01 ` JPT
0 siblings, 1 reply; 3+ messages in thread
From: Martin K. Petersen @ 2022-02-23 4:00 UTC (permalink / raw)
To: Randy Dunlap; +Cc: JPT, linux-kernel, linux-block
Randy,
>> I wonder why safecopy always says
>> Reported hw blocksize: 4096
>> Reported low level blocksize: 4096
>>
>> even if the medium is floppy (512) or CDROM (2048)
>>
>> is this a kernel issue always assuming min 4k block size?
Not sure how safecopy queries the block size. The kernel supports
devices with 512, 1024, 2048, and 4096-byte logical blocks.
--
Martin K. Petersen Oracle Linux Engineering
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: blocksize 4096 even for floppy and CDROM?
2022-02-23 4:00 ` Martin K. Petersen
@ 2022-02-27 11:01 ` JPT
0 siblings, 0 replies; 3+ messages in thread
From: JPT @ 2022-02-27 11:01 UTC (permalink / raw)
To: linux-block
Hi,
seems that safecopy always assumes 4096, while ddrescue always assumes 512.
you have to specify the blocksize manually for both programs.
thanks
Jan
Am 23.02.22 um 05:00 schrieb Martin K. Petersen:
>
> Randy,
>
>>> I wonder why safecopy always says
>>> Reported hw blocksize: 4096
>>> Reported low level blocksize: 4096
>>>
>>> even if the medium is floppy (512) or CDROM (2048)
>>>
>>> is this a kernel issue always assuming min 4k block size?
>
> Not sure how safecopy queries the block size. The kernel supports
> devices with 512, 1024, 2048, and 4096-byte logical blocks.
>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2022-02-27 11:00 UTC | newest]
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[not found] <e4ab39cb-fbe7-1148-8d8a-5cd46866159f@gmx.net>
2022-02-22 23:24 ` blocksize 4096 even for floppy and CDROM? Randy Dunlap
2022-02-23 4:00 ` Martin K. Petersen
2022-02-27 11:01 ` JPT
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