Firewire and YDL 3.0

[Geert Janssens]

Derick Centeno wrote:
> Has anyone out there run into the situation as I describe it here?
> I resurrected an internal old 4G IDE HD (the original HD in the Beige G3 
> Minitower) and install it into a external housing turning it into a 
> Firewire drive.  Mac OS 9.2 reads the thing fine, even Mac OS 8.6 reads 
> the Firewire drive without difficulty.
> 
> However, pdisk reports the Firewire drive as existing on /dev/sdb; isn't 
> that reserved for scsi drives?  Doesn't Red Hat Linux know yet how to 
> distinguish Firewire drives?
> 
Linux tends to use scsi emulation for quite a few things. Apparently 
this also goes for firewire. So when you connect a firewire device to 
your computer, linux will present it in the system as if it was a scsi 
device.

> As a test I decided to put some files onto the Firewire drive which I 
> would immediately recognize when viewed from Linux.  When I finally 
> mounted the drive which pdisk told me was /dev/sdb5, a string of unknown 
> files appeared along with the following string, - without the quotes 
> -"Where_are_my _files?"
> 
What you see ("Where_are_my_files?") is in fact a small text file that 
explains you are looking at a HFS+ filesystem from a system that only 
understands HFS.

So this most likely means that your drive is HFS+ (or "Mac OS Extended" 
as Apple calls it) formatted, and your kernel doesn't support HFS+.

Apple introduced HFS+ in MacOS 8.1. Older versions of MacOS don't know 
about HFS+, and hence can't access files on such partitions.

So if someone wants to read a HFS+ formatted disk on an older system 
(pre 8.1), he/she wouldn't find any information.

Normally, an OS that finds a disk it can't read proposes to format it 
into a format that is can read. But since HFS+ was the future file 
system for their MacOS, Apple decided to be more careful here. So 
instead they made sure that HFS+ at least showed the 
"Where_are_my_files?" file on these older machines by fooling those 
systems into believing that a HFS+ partition is really a HFS partition 
with only one file, explaining what is going on.


By the way, the other files you see ("Desktop DF", "Desktop DB", 
"Finder" and "System") are files used by Mac OS to organise its desktop. 
You don't see these files under MacOS since there they are treated as 
hidden files.
In Linux, only files starting with a "." are considered hidden. Since 
these files don't start with a dot, they are shown with a standard ls 
command

> I thought that was absolutely cute.  It didn't tell me anything, but I 
> thought it was cute.  If the phrase does have a meaning, by all means 
> drop a line and let me know; I think Linux was trying to make sense of 
> something which made no sense to it.
> 
If you had the experimental HFS+ kernel modules compiled in or loaded as 
modules, you could read this hard disk as well in linux.

In the other case, I would recommend you format this disk in MacOS as a 
regular HFS disk (Mac OS Standard) instead of HFS+ (Mac OS Extended). 
Then you would be able to read and write to the disk with no problems 
under linux.

Cheers,

Geert