Boot partition beginning past 1024 cylinders

  • Thread starter Thread starter Tom Del Rosso
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Tom Del Rosso

Trying to make 3 or 4 bootable partitions on one disk is getting a little
tight. Where do we stand with the limit on the first cylinder of bootable
partitons? Have the BIOS standards people dealt with this yet, or do boot
managers work around the problem ok?
 
Tom Del Rosso said:
Trying to make 3 or 4 bootable partitions on one disk is getting a little
tight. Where do we stand with the limit on the first cylinder of bootable
partitons? Have the BIOS standards people dealt with this yet, or do boot
managers work around the problem ok?
Click to expand...

BIOS is not involved with partition bootrecords, the MBR bootcode is. So
it depends on the MBR bootcode. Newer OSes use Int13ext instead of Int13.
 
Tom Del Rosso said:
Trying to make 3 or 4 bootable partitions on one disk is getting a
little tight. Where do we stand with the limit on the first cylinder
of bootable partitons? Have the BIOS standards people dealt
with this yet, or do boot managers work around the problem ok?
Click to expand...

Yes, its perfectly possible for a boot manager
to ignore that limit and any decent one does that.
 
Trying to make 3 or 4 bootable partitions on one disk is getting a little
tight. Where do we stand with the limit on the first cylinder of bootable
partitons? Have the BIOS standards people dealt with this yet, or do boot
managers work around the problem ok?
Click to expand...

I believe I've used XP's bootloader to boot both XP and Linux (via LILO)
partitions past 1024. With the bootloader is in the first partition, the
actual system partition can be anywhere. Never could get BeOS to load
that way however - guess it's too old.
 
Previously Tom Del Rosso said:
Trying to make 3 or 4 bootable partitions on one disk is getting a little
tight. Where do we stand with the limit on the first cylinder of bootable
partitons? Have the BIOS standards people dealt with this yet, or do boot
managers work around the problem ok?
Click to expand...

Booting with a reasonably new boot manager should not be a problem.
I use Grub, which boots both Linux and Windows XP without problems.

Arno
 
In Tom Del Rosso va escriure:
Trying to make 3 or 4 bootable partitions on one disk is getting a
little tight. Where do we stand with the limit on the first cylinder
of bootable partitons?
Click to expand...

Nowadays, the only relevant limit is that you need to keep your booting disk
below 2TB (MBR architecture).
The last mainstream OS release with a 1024-cylinder limit was Windows NT4
(end of extended support this month.)

BTW, the first cylinder only matters with respect to the MBR code; after it,
the boot loader may also have issues, and it would be the last cylinder of
the partition which would matter (in fact, the highest cylinder of the files
used, which could be significantly lower, but it is a bad idea to play with
that.)

Have the BIOS standards people dealt with this yet,
Click to expand...

Yes, around 1992.
or do boot managers work around the problem ok?
Click to expand...

They do quite well, for quite some time now.


Antoine
 
Tom Del Rosso said:
Trying to make 3 or 4 bootable partitions on one disk is getting a little
tight.
Click to expand...

What does "getting a little tight" mean? Partition limits of 4 primaries or
3 primaries + 1 extended are imposed by MS HD architecture, that hasn't
changed. But you can use BootIt NG unlimited partitions to get around that
limitation (w/ caveats).

Where do we stand with the limit on the first cylinder of bootable
partitons?
Click to expand...

What limit? First sector is the boot sector, you referring to that? A good
boot manager can be loaded from first sector, from which most any OS can be
booted from your other primaries.

Have the BIOS standards people dealt with this yet, or do boot
managers work around the problem ok?
Click to expand...

Not a BIOS issue, HD architecture issue specific to Microsoft.

Jim
 
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