Syslinux - Jun 2015 - Status of support for secotr sizes >512b

Hello,

can someone give me a short summary on the status of support for sector
sizes >512bytes in SYSLINUX?

The installer obviously still doesn't support it, at least it complains
about "unsupported sector size" when used on a 4k-sector disk. I read
somewhere that this is only a problem of the installer, and that
SYSLINUX itself would work if it got installed "by other tools".
Unfortunately, I found no hint as to what other tools could be used for
this.

Thanks,
Andreas

On 06/01/2015 03:11 AM, Andreas Heinlein via Syslinux
wrote:
> Hello,
> 
> can someone give me a short summary on the status of support for sector
> sizes >512bytes in SYSLINUX?
> 
> The installer obviously still doesn't support it, at least it complains
> about "unsupported sector size" when used on a 4k-sector disk. I
read
> somewhere that this is only a problem of the installer, and that
> SYSLINUX itself would work if it got installed "by other tools".
> Unfortunately, I found no hint as to what other tools could be used for
> this.
> 
There aren't any other tools at the moment for BIOS, due to the lack of
an implementation which can actually test.  It should work on (U)EFI
since those systems don't require any special tools to install Syslinux.

	-hpa

> Hello,
> 
> can someone give me a short summary on the status of support for sector
> sizes >512bytes in SYSLINUX?
> 
> The installer obviously still doesn't support it, at least it complains
> about "unsupported sector size" when used on a 4k-sector disk. I
read
> somewhere that this is only a problem of the installer, and that
> SYSLINUX itself would work if it got installed "by other tools".
> Unfortunately, I found no hint as to what other tools could be used for
> this.
> 
> Thanks,
> Andreas
 
Yes, that's the current status.

_ Many (partition editor, filesystem formatting and other) tools do not 
correctly support bytes_per_sector values other than 512.

_ Many BIOSes do not correctly support bytes_per_sector values other 
than 512.

_ syslinux.efi should have no problem with 4096 bytes per sector.

_ chain.c32 should have no problem with 4096 bytes per sector.

_ Some multiple-connectors devices (e.g. with both, USB and SATA or 
eSATA connectors or external drive enclosures) might use (or present 
themselves, or show, or report, or force) a different bytes_per_sector 
value, depending on which type of connection / controller is used. 
There _might_ be workarounds in some of these cases (e.g. using some 
steps involving "loop" devices, instead of directly referring to the 
original device).

_ Some devices have 4096 bytes per sectors, but are able to use a 512 
bytes per sector "logical" value ("512e").

_ There might be a need to use the "55AA" magic number signature for 
the MBR and for VBRs in *every* "510-511th" byte count (counting from 
zero to 511) of the corresponding sectors; i.e. the "55AA" magic
number
should better be present 8 times in a 4096 bytes_per_sector MBR and/or 
VBRs, once every 512 bytes in the relevant sectors. These magic values 
might need to be introduced / edited manually.

_ Other conditions, not necessarily related to 4096 bytes per sector 
but regarding Syslinux, might be required (e.g as of 6.03, Syslinux 
supports a 4KiB_per_cluster value for NFTS, but bigger values are not 
yet supported).

_ If some auxiliary tool manages to install SYSLINUX/EXTLINUX on a
"4k"
device, then Syslinux should have no problem with 4096 bytes per 
sector.


I don't know how much stable / usable / predictable the behavior of 
other bootloaders is on this type of devices.

So, it is not just a matter of Syslinux supporting these devices; there 
are other factors in play.

Regards,
Ady.
 
> _______________________________________________
> Syslinux mailing list
> Submissions to Syslinux at zytor.com
> Unsubscribe or set options at:
> http://www.zytor.com/mailman/listinfo/syslinux
>