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GRUB - Bugs: bug #19410, Unable to Create Logical Partition...
bug #19410: Unable to Create Logical Partition with "partnew" Command
| Submitted by: | Steve Burtchin <sburtchin> | ||
| Submitted on: | Sunday 03/25/2007 at 09:27 | ||
| Category: | Disk & Partition | Severity: | Major |
| Priority: | 5 - Normal | Item Group: | None |
| Status: | None | Privacy: | Public |
| Assigned to: | None | Originator Name: | Steve Burtchin |
| Open/Closed: | Open | Release: | 0.97 |
| Reproducibility: | Every Time | Planned Release: | |
Rich
Markup
| Sunday
03/25/2007 at 09:27, original submission: First: The problem described in this bug report has
been solved (by creating the "eptedit" function) and thoroughly tested by
me on my Compaq Deskpro EN. For reference see How
To Write Extended Partition Tables from GRUB?. Second: I would have thought this to be a feature
request, but . . . from the GRUB Legacy Patch Submission Policy: "If your system is technically impossible to be booted only with
existing features and your patch addresses that problem, it is a
bugfix." So maybe this is a bugfix - ??? - I'll let someone else decide that.
Third: If GRUB Legacy maintainers want to classify
this as a new feature, I will gladly volunteer my time to become a
maintainer for the "eptedit" function. Why I Need to Create Logical PartitionsThe attached files "PriMastr.png" and "SecMastr.png" show the partition
layouts for the three HDD's used in my flexible multiboot system. What is
obvious is that there are much more than four Primary partitions defined
for each of the internal HDD's. The highlighted Primary partitions are
standard. The others can be swapped for the standard ones to address
specific boot situations. Note also, that this multiboot includes at least
two 'non-LBA aware' operating systems, and that the standard Extended
partition continues past the 1024th cylinder. The Extended partition on
the second HDD also contains three Logical partitions dedicated as
'scratchpads' for sharing data between all operating systems, so it is
essential that these three Logical partitions are visible to all of them.
The only way this is possible without risking the potential for data
corruption, is to define a smaller Extended partition for the 'non-LBA
aware' operating systems. I also want to have the DOS5 and Win3.1
partitions contained within the Extended partition, rather than defined as
Primary partitions, because this makes it much more convenient for making
image backups (as opposed to creating a custom boot configuration to image
each OS partition). How It Will Be Used (Mostly, but see "Other Potential Uses")The attached file "mbr2std.png" shows what the MPT of the second HDD
should look like when booting most of the 'LBA aware' OS's. In this
situation, the file "b15_std.png" shows the EPT that should be found at
LBA 7680960. The attached file "mbr2dos5.png" shows what the MPT of the second HDD
should look like when booting MS-DOS 5.0, and the file "mbr2Win3.png"
shows what the MPT of the second HDD should look like when booting Windows
3.1. In these situations, the file "b15_old.png" shows the EPT that should
be found at LBA 7680960. Note that the DOS5 and Windows 3.1 partitions are
defined as both Primary and Logical partitions in this configuration. I
could have redefined the start of the Extended partition for these two
OS's, but the documentation was made simpler by just hiding the Logical
definitions (this seems to have no ill effects). The most significance differences between these two situations is the
size of the Extended partition, and the EPT at LBA 7680960. The "partnew"
command is used to fix the MPT. The "eptedit" command is used to zero out
the second slot of the EPT at LBA 7680960 for booting MS-DOS 5.0 and
Windows 3.1, and to put the data back into this EPT for booting the 'LBA
aware' OS's. See the file "MenuItms.txt" for excerpts from my "menu.lst".
You may be wondering why the "geometry" function is called within my
"menu.lst" file. In the process of testing this new function, I discovered
another bug: GRUB apparently forgets at least some of the geometry
information. When the "eptedit" function performs validation checks on
some of the input parameters, a check against invalid information in
memory results in "Error 18". Issuing the "geometry" command refreshes the
geometry information for the disk, and avoids the error. I could easily
avoid the error by not performing input data validation, but I don't like
hiding problems. The PatchThe syntax is like this: Most parameters are easily calculated or obtained with freeware
utilities. "SLOT" can be "C" (current) or "N" (next). "PART" and "TYPE"
are as for the "parttype" function. Most of the new "eptedit" function is based on code borrowed from the
"parttype" and "partnew" functions. See the attached "builtins.c" file.
Other Potential Uses for "eptedit"
What Next?I will agree to maintain the "eptedit" function if that is necessary.
I should write the information for the GRUB Manual. What file do I edit
for that? Can someone help me get started writing ChangeLog? Is
there a template or standard format I have to follow? What other files do I need to attach to this bug report? What do I have to do to get the "eptedit" function into GRUB
2. Is it stable enough yet that I can test it on my working
computer? How do I get involved with GRUB 2 development? |
Steve Burtchin <sburtchin> |
Depends on the following items: None found
Items that depend on this one: None found
Steve Burtchin
<sburtchin> added by sburtchin (Submitted the item)
adrian15 <adrian15>
added by sburtchin
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Follow 10 latest changes.
| Date | Changed By | Updated Field | Previous Value | => | Replaced By |
|---|---|---|---|---|---|
| Sunday 03/25/2007 at 09:38 | sburtchin | Attached File | - |  |
Added builtins.c, #12291 |
| Sunday 03/25/2007 at 09:31 | sburtchin | Attached File | - | |
Added mbr2dos5.png, #12287 |
| Attached File | - | |
Added mbr2Win3.png, #12288 | ||
| Attached File | - | |
Added b15_old.png, #12289 | ||
| Attached File | - | |
Added MenuItms.txt, #12290 | ||
| Sunday 03/25/2007 at 09:27 | sburtchin | Attached File | - | |
Added PriMastr.png, #12283 |
| Attached File | - | |
Added mbr2std.png, #12284 | ||
| Attached File | - | |
Added SecMastr.png, #12285 | ||
| Attached File | - | |
Added b15_std.png, #12286 | ||
| Carbon-Copy | - | |
Added adrian15 |
