my USB flash was divided into two partitions, the first one serves
as a normal partition for file saving and the second one is only for
booting purpose, all the livecd are saved in the second partition managed
by grub2, the configuration files are placed in the attachment, to have it
bootable in both legacy bios mode and uefi mode, you will have to install
grub2 in two ways for targets, one is the i386( called like this in
grub2),another is x86_64-efi, I install it with the following commands:
grub-install --removable --recheck --target=x86_64-efi
--efi-directory=/run/media/root/r\&t
--boot-directory=/run/media/root/r\&t/boot/grub/x86_64-efi
grub-install --recheck --removable --target=i386-pc
--boot-directory=/run/media/root/r\&t/boot/grub/i386-pc /dev/sdb
before the two commands, you should already have the target
partition mounted on the right place( here is /run/media/root/r\&t/ ), the
i386-pc targets need write data to mbr, while the x86_64-efi boot from efi
excutable file which is loaded directly by bios with uefi support, that's a
feature of uefi. As for 'secure boot', it's so called but it prohibit any
loader unsigned or signed with a wrong key( more often the key belongs to
Microsoft, but for some machine you can also install your own key), about
how to boot with secure boot on, here is some more detailed refrence:
www.rodsbooks.com/efi-bootloaders/index.html
an announcement about 'secure boot' by fsf two or three years ago:
http://www.fsf.org/campaigns/secure-boot-vs-restricted-boot/statement
the two targets share nearly the same configurations which are
located in /boot/grub/grub2_share/cfg, some file were removed to shrink the
file size, so it's not ready to boot, but the arrangement of the file can
be referenced.
the main file for sagemath is placed in the same path as they are
arranged in the live img, here in my USB flash, it's the directory '/live',
the corresponding configuration is in 0_gnu_linux.cfg.
among the files, /boot/grub/grub2_share/cfg/*.cfg and
/boot/grub/$target/grub/grub.cfg is what you can refer, the other files
were left just in case that you need.
在 2015年7月25日星期六 UTC+8下午7:50:01，rt.写道：
>
> e.. not really, I'm just a junior student now and interested in computer
> techniques.
>
> sorry to reply so late, we are having a field work and these days it seems
> that the ipv6 was not available or not stable enough, I was blocked and
> can't have access to google, so is this forum. Just now, I tried several
> times and finally I am lucky to send this message!
>
> grub2 is of course a free software, it's also made by GNU project as an
> update to legacy grub! As for my grub2 configuration, it seems that it will
> take some space to write it. I will try to conclude it here. Besides, you
> can find more instruction about it in the official manual.
>
> there is a great chance that you will have to fsck your usb flash disk, at
> leastfor sage live 6.5 or earlier 6.4, but that's easy to deal with and
> still acceptable. for the new version 6.7, I'm not sure as my laptop is now
> more convinient, so I haven't got to try the new version now.
> It should be claimed that not only sagemath, but also many live cd would
> couase the problem, and sagemath have tried to deal with this issue through
> several more convenient methods, though it's not auto done now.
>
>
> it is little long to say about the boot mode uefi and legacy bios, it's
> better that you find the explanation somewhere else, two place I recommend
> is the uefi official webset and tiannocore, as I first learned it from all
> kinds of forum, most of which were wrote in Chinese ...
>
> as for matlab, I just leared little, and it was already one year ago. as
> now I don't want to spend much time on it, I can't tell much about it,
> sorry. However, for matlab, there is a big problem, it's not free, not only
> the charge but also not open source; also, it takes lots of disk space( my
> hard disk is just a little inadequate to save all my files). Several weeks
> ago, I tried ansys under the linux, finaly got defeated and will never want
> to have ansys installed on linux again, there is so many troubles with it,
> and hardly have documents, I'm afraid that matlab would have the same
> circumstance, but that's just the third reason. Now sagemath is just
> powerful enough and script is so convenient to use. With additional tools,
> like a frontend( for example texmacs, with witch the formula displayed is
> easy to read ), it can meet nearly all what I need, there is no reason for
> me to try matlab again.
>
> maybe later I will try to add a map to illustrate how the grub2 works for
my USB flash, hoping the net will hold on ...
it seems it's no easy to upload files here, I will try to make it later..
>
> 在 2015年7月22日星期三 UTC+8上午3:35:08，Dominique Laurain写道：
>>
>> Hi rt,
>>
>> you are advanced student, aren't you ? ... :-)
>>
>> yes, it will be good to share about grub2 like Thierry did/does for his
>> technical data...either in your own blog or you post it for some interested
>> sage users or dev.
>>
>> I know only "grub" at my job, but maybe grub2 is more up to date. I guess
>> many "details" are very important : how did you partition disk to handle
>> the boot process from the grub to the chosen ISO file ? is grub2 free (no
>> money to pay to install it) ? ...
>>
>> I don't know just now, what it means "uefi" or "secure boot is off" ...
>> you can write short explanation (or reference websites) about what you did
>> (no need to mention what you have not tried yourself).
>>
>> MATLAB can have advantages too : if you have the chance (for example
>> usage free with school) to use MATLAB, do it...you will understand you
>> didn't miss opportunity later,... you can compare and explain better your
>> ideas why SAGE is very good. Keep written notes about good or bad
>> experiences.
>>
>> Dominique.
>>
>
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