One of the secrets of success in a complex installation like this is to completely understand exactly where everything is on disk. Acronis disk director could list some of the info, but I needed more. I wrote a tool to take the info that Acronis displayed and produce a table for my notes...
MBR, the hidden sectors, and the EBR's
The Master Boot Record (MBR) is the first sector of the disk. It has the boot code and the partition table in it. The rest of the first track is called "the hidden sectors". In my case, Grub stage 1.5 is in the hidden sectors. The structure of this first track is duplicated for each logical partition. Each logical partition has a structure like a MBR as it first sector. Then the rest of the first track is ignored. This first track immediately precedes the logical partition that it describes. Microsoft uses the term "logical drive" which almost means the same thing as "logical partition". But looking carefully at the definitions it seems to me that "logical drive" = EBR + "wasted sectors" + "logical partition". In any case, you need the MBR and the EBR's to define the partition layout of a drive. I see programs to backup the MBR but they always ignore the EBR's. I will fix that by writing a utility to backup the MBR plus the EBR's. Strickly speaking the EBR is one sector and it is followed by some wasted sectors. In my chart I have cheated a little bit and redefined the EBR to be all overhead sectors between partitions. I feel that the chart is "busy enough" and would be even harder to read with two lines between each partition.
Cylinder Alignment
Notice how the partitions are generally aligned on cylinder boundaries. The exception is /mastergrub and this is due to a bug in Acronis Disk Director. I originally had /mastergrub at .5 MB which is too big. I shrunk it, but I made the free space appear before the partition rather then after it. (This let me shuffle the free space down and add it to my XP partition.) When I produced this chart, I noted that /mastergrub was not aligned properly. This wastes a few more cylinders, but it seems to have few consequences. The only potential problems that I can think of... Some programs try to guess the disk geometry....with amazing success. They might do this by looking at the alignment of the partitions. Some programs (like Acronis itself) can locate and restore deleted partitions. This might fail if the partition was misaligned to begin with. I notice that Acronis has a "fast" and "slow" search for deleted partitions (with the "slow" option being more robust) and this might push you into the "slow" option.
This encouraged me to experiment with partitions that were truly logical but also had an entry in the fourth MBR slot as a primary partition. My idea was to switch one of several logicals into the primary slot, install an OS, destroy the primary entry, and boot from the logical partition. This did not work very well. A smart bootloader could switch a partition from logical to primary and then boot it, but I did not want to write a bootloader.
I notice that each logical partition is wasting most of a full track. I am considering misaligning all of the partitions to recover that space. There is not a lot of space to be recovered and this may not be worth the effort. Also Acronis does not have enough control to allow me to try. I believe that qtparted can do this though.
Solaris Changed Types
Solaris 10 is using BF as its partition type and the Solasis 10 installer does not recognize partition with a type of 82 anymore.
I did not want to enter the starting and ending LBA's for the EBR's. The script should be able to calculate them from the preceding and following entries. This increased the complexity of the script but in the long run it saved effort. And here is the source code...
I have an x86 Sun server, with no CDROM drive and no OS currently loaded on it. I need to install CentOS on it... trying to figure out how to do that.
I've heard there are ways to connect to the serial management port, and mount a laptop's CDROM drive as a drive the server will recognize to... (0 Replies)
Hi to all,
I have the problem that a laptops with windows XP cannot startup even in safe mode nor using last good known configuration. I have a Ubuntu 10.10 Live CD and booting from it I can read the Hard Drive.
I need to do a backup the Hard Drive from XP laptop and I want to connect this... (5 Replies)
Hej guys,
I'm doing some simple matrix operations with octave and don't know where and how it stores it's variables. Is there any file somewhere that could be accessed?
I was using MATLAB before and now Octave is new for me.
Or maybe I should use some commands to save and load it.
but... (0 Replies)
Hej all,
I have an script which I run it with Octave command in Linux, I want to know how could I put bash commands like grep and sed and use them together with octave?
My Octave script:
Script.sh:
m = load ("file", "-ascii")
for i=1:10
g(i)= sin(m)
end
and then I use this... (2 Replies)
Hi all,
Good day. I just installed RHEL6.3 into my laptop to learn RH.
There is an existing Windows 7 in there.
After installing the RHEL, the laptop will just boot to Windows 7.
I tried to use this BCDedit to add Linux entry to the boot menu, BUT each time i pick the redhat selection,... (5 Replies)
This is probably something really simple, but I don't get it. I downloaded a copy of Octave and extracted it to octave-2.1.73-sol10-sparc-local. Now what do I do with it? I chmod'ed it to 777 and tried running it which just gave me an endless stream of errors. Here's the beginning of the file... (4 Replies)
Dear all,
I would like to transfer my old laptop documents/files etc to the new laptop without using any external hard disk.
Please let me know if its possible via any way.
Thank in advance,
emily (3 Replies)
10-07-2006