[OpenBIOS] Filesystem code in BIOS

Alexander Viro viro at math.psu.edu
Sun Mar 1 00:54:31 CET 1998

On Sun, 1 Mar 1998, Benjamin Scott wrote:

>   With efficient code and data compression, 128K goes a long way. 
> Remember, UNIX used to run on systems with 128K total main memory.  I
> would hope we would be able to implement a glorified bootloader in that
> space.  :-)
	Less than 128, BTW.
> AV = Alexander Viro <viro at math.psu.edu>
> AV> Why? What kind of filesystem should it understand? FAT??? Damn,
> AV> I'ld prefer not to have the stinker around at all.
>   FAT has two key advantages: It is very simple, and it is nearly
> universal.  The first helps us keep our code size down and minimizes the
> possability of bugs.  The second is useful in emergency situations.  I
> don't think I've met a microcomputer OS yet that didn't have some way to
> support FAT (either built-in or with add-on software).  That can be very
> handy if you need a kernel in a hurry and the only other networked
> machine around is a Mac or some such thing.  :-)
>   FAT actually bears a strong resemblence to the "stand" filesystems
> some UNIXes use to boot.  Such filesystems are typcially limited in
> filename length, have no security, and are flat (no directories).  FAT
> isn't ideal for this, but suits the purpose, and like I said, is nearly
> universal.
	Let me summarize my objections against FAT.
a) 8+3 limit. Single dot limit. (I.e. no names like kernel-2.0.33)
b) Extremely fragile (lists are much more fragile than trees)
c) EXTREMELY FRAGILE just because DOS (shrug) or Sucks95 (BARF!) can
access it.
d) Nontrivial loaders (other than get the first sector of some partition
and let it run) are needed only for Linux and *BSD. On these systems we
can add a new filesystem.
e) If you managed to hose read-only mounted filesystem in Linux/*BSD it
means that you hosed all your disk. It is not an easy job, believe me.
Then you'll have to boot from floppy anyway. I keep Linux boot floppies
around, but DOS? What for? And if you don't have Linux/*BSD you don't need
filesystem with kernels at all, so for UNIX-free machines it's non-issue.

Conclusion: hell with FAT. If we need a filesystem let's implement a
good one. It's not that hard.
Sucks95 users are extremely stubborn - each time when M$ tech support
advices them to install an OS they install you-know-what...

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