[syslinux] isohybrid has 2 variants

[Ady]

> Hi,
> 
> i have written an introduction to isohybrid and put it on
> the discussion page of the ISOLINUX wiki.
> 
>   http://www.syslinux.org/wiki/index.php/Talk:ISOLINUX#Proposal_for_description_of_isohybrid
> 
> Review and proposals are appreciated.
> 
> The reference to "above mkisofs command" anticipates the final
> position of this text at the end of
>   http://www.syslinux.org/wiki/index.php/ISOLINUX
> 
> 
> Not yet covered are:
> 
> - The topic how to produce an UEFI boot image (FAT filesystem)
>   which can be used with option -e of genisoimage or xorrisofs.
> 
> - The topic how to bring the isohybridized image onto an USB stick.
>   (Especially on MS-Windows ...)
> 
> 
> Have a nice day :)
> 
> Thomas
 
Here are my personal opinions / comments. The items do not follow any 
particular order, and I might be slightly overlapping or repeating 
some of them. My apologies.

_ Wiki should use more user-friendly language and "less deep" 
technical information.

_ In the Syslinux wiki, "PC-BIOS" should rather be called plain 
"BIOS".

_ Specific ISO-building tools should not be part of the generic 
explanation, but rather a separate section, such as "Examples".

_ Specific details (e.g. about the usage of the respective 
ISO-building tools) should be searched in the respective 
documentation for each tool, not in the Syslinux wiki. There are 
several reasons for this point.

_ It should be clear for a common reader that any commands involving 
ISO-building tools are just very basic examples, and _not_ to be 
taken as "this works on every case for every need and this is all you 
need to type in so to make it work".

_ Mentioning paths for specific distros should be avoided if 
possible. The respective information, in case it is needed by the 
user, should be search in the relevant distro's documentation / 
packages / tools / maintainers.

_ When a command or tool works only under certain OS or OS-type (e.g. 
Linux), this fact should be mentioned.

_ Technical details that are usually also found in other sources 
(e.g. in Wikipedia) should be reduced to the minimum necessary for a 
common user/reader. Most common users would be searching an 
explanation if isohybrid's command line options, or the appropriate / 
relevant / preferred use case of one bin file over the others. Other 
users would be looking for a "HowTo" or to solve some problem. When 
information is too-technical, or the wording sounds too-technical, 
most users won't even read it.

_ The different iso*.bin files should be explained in one wiki page, 
and not to be repeated but rather linked to. They should be explained 
_either_:
 _ in the "mbr" page (where other alternative *.bin files are already 
mentioned); or,
 _ in the ISOLINUX page; or,
 _ in the new "isohybrid" page,

but only in one of them.


_ The specific wiki formatting is not important at this time.

_ The firmware "target(s)" can be different than the one used by the 
host where the ISOLINUX and/or isohybrid image is being built. 
Multiple simultaneous firmware targets are allowed (although this 
possibility depends on the variant and version of the isohybrid 
program too).

_ Eventually "isohybrid" should be a separate page in the wiki, and 
not part of the ISOLINUX page. Adding relevant links can be done 
later.

_ Relevant items for common users:
 _ command options supported by each isohybrid variant;
 _ if the version of the isohybrid program should match the version 
of ISOLINUX (perhaps depending on isohybrid variant, or version that 
includes a new feature, or ISO-building tool used, or...), this fact 
should be clearly mentioned.
 _ if different iso*.bin files are to be used for different needs, 
then each case should be clear for the common user.
 _ What to do with the resulting ISO image; (write to optical media, 
or to USB drive - users should search for specific details / methods 
elsewhere). This is already mentioned in the ISOLINUX page, but when 
a separate "isohybrid" page is created this information should be 
part of the new page (and not repeated).
 _ xorriso builds the ISO image, and it can (optionally and) 
simultaneously make it isohybrid too. This is an _alternative_ 
method.
 _ The different _alternatives_ should be clear to a common user, 
specially to avoid confusion with "serial-like" steps.
 _ Yet, the steps should be "generic", as opposed to getting into the 
details that are already part of tools' documentation and distros' 
wikis. Basic examples should be OK, as long as the user understands 
that these are basic pointers and not the full extent of the 
documentation for each ISO-building tool.
 _ This wiki page should focus on the isohybrid variants and their 
available options / differences. This page should not be covering 
"how to build any ISO image from any source of files using each and 
every tool available in whichever OS for every goal any user could 
think about".

_ BTW, mkisofs supports building ISO images for EFI, but the specific 
arguments 
are different than those used by xorriso.

Thank you,
Ady.