Re: I write a patch for Japanese NEC i386 old computers.

["Hitoshi Ozeki" <h-ozeki@ck2.so-net.ne.jp>]

Hello, all.

1. name of architecture.

In Japan, The 'PC-98' means the NEC PC-9800 series and its compatible
machines.
But, In the other country, 'PC98' means a hardware standard set by Microsoft
and
a consortium of hardware manufacturers.
I afraid to mistake, so named as 'NEC98'. But, I do not have a intent to
persist this name.

2. sharing of code with PC's.

Sharing of code with PC's bring me several problems.
Firstly, In this time, My patch includes a lot of PC's code. But amount of
the PC-9800 depended code will increase.
Secondaly, when changes PC's depended code, PC-9800 code shuld change also.
I think GRUB2 is next generation
of GRUB, not on the stable.

3. known bugs/problems of patches in this time.

* Scroll routine of console has a bug, bares trashes on the lowest line.
Should fix.
* Remains code of VGA and VBE, I'll replace to PC-9800 graphics routine.
* In the high-rezo mode, I do not have tested, not have any datasheet and
machine.
   (NEC released a few high-rezo supported machines, so this is little
problem.)
* Algorythm of transfering from LBA to CHS, I have trusted the answer of
BIOS. Should compute myself.(difficult)
* SASI/ATAPI device is not supported, should support this.(difficult)
* Listing devices by 'ls' command. when exists not-ready removable device,
its command ends with fail.
* cannot boot the FreeBSD(pc98). Should fix.
* 'play' command is not tested.
* On booting the Linux with framebuffer console,  cannot display correctly.
* First NEC PC-9801, PC-9801E, PC-9801F, and PC-9801M are not supported.
Support those.(not a big problem.)

4. Wish to discuss.

* Support of different sector-sizes, MO(Magneto Optical) disk uses
512/1024/2048 b/s(bytes per sector).
  CD-ROM uses 2048 b/s, FD of formatted by PC-9800 series often uses 1024
b/s, Old OS uses 256/128 b/s.
* When doing 'chainloader' command, the all disk devices cannot use via
'dev.c',
  because of doing 'grub_loader_unload_func'  on 'grub_loader_set'.
  I think it is disirable to do 'grub_loader_unload_func' on 'grub_*_boot'.

I try to fix this patches, and disclose in future.

Regard,

-- 
 Hitoshi Ozeki h-ozeki@ck2.so-net.ne.jp