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Re: Request for a Debian CD logo



OS-BADGE-ICONS is nominally a very simple format, but unfortunately the
sands of time have erased it from the memory of the Web, and the memory
of hackers like me who used to understand it.

The header is width x height.  "1010" for 16x16 icons.  There is an
extended format used by OpenBSD which is 32x32, but they only use 27
rows so they have "201B" as the header.  I don't recall what the system
does with non-square icons; I *believe* it centres them.

There are three icon grids; the hex chars are serialised literally.  For
example, the first line of the typical penguin icon is:
000000000000F8FEACF6000000000000 - this means a bunch of 00 bytes
followed by F8, FE, AC, F6 followed by more 00 bytes.

The third 'grid' component is an alpha mask.  I do remember this.

One brain-wave that I just had is that I'm thinking these are Apple ics8
format icons; the first is the normal icon, and the second is the
'selected' icon (since the background changes, you may want the icon to
change too).  But I may be wrong.  This was all many, many years ago.

I also want to note that while most of your bootinfo.txt/ofboot.b file
has to have capital SGML tags (this predates XML!), because some Mac OF
won't accept it if CHRP-BOOT/COMPATIBLE aren't all-caps, you need to
ensure "boot-script" is always uncapitalised.  This is to ensure
compatibility with SLOF, as used in late-model IBM pSeries systems and
also QEMU:

https://github.com/aik/SLOF/blob/master/slof/fs/packages/disk-label.fs#L472

Otherwise, SLOF will say your boot script is invalid because it couldn't
find the string "<boot-script>" in it.

The xorriso params that we pass in Adélie to have successfully booting,
GRUB 2-based PPC/PPC64 media, are:

-hfsplus -isohybrid-apm-hfsplus -hfsplus-file-creator-type chrp tbxi
boot/ofboot.b -hfs-bless-by p boot -sysid PPC -chrp-boot-part

Our image creation scripts are at https://code.foxkit.us/adelie/image/ -
you would probably be interested mostly in iso-params-ppc and
post/arch/ppc.sh (which is an arch-specific script that runs after the
file system is created but before xorriso is called).  Note that you can
have a pretty icon in the Finder on Mac OS X by generating a modern
.icns file and copying to the root of the disc as 'Icon^M'.  Yes, that
is an escape sequence, and means Icon\r.

I don't know if any of this is even still relevant or helpful, but I
hope that this may help out future hackers boot up PowerPC systems.

Best,
--arw


-- 
A. Wilcox (awilfox)      - Unix since '97, Linux since '01
Libre programmer (C/C++) - contracts available
Bio: http://foxkit.us/   - Distro: https://www.adelielinux.org/

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