Re: Prosel-1

[fadden@uts.amdahl.com (Andy McFadden)]

In article <4fllzKG00YUoA4ZFUp@andrew.cmu.edu> gregt+@CMU.EDU (Gregory Ross Thompson) writes:
>  ProSel-16 does a lot of things wrong becuase it used to bypass all
>the FSTs.  When the HFS FST came out, Glen changed a heck of a lot of
>code so that it could be used on HFS disks.  It's pretty robust.  I'm
>happy with it.

Well, no.  As of v8.81, it still used the old ways on ProDOS volumes, but
did things the "right" way on non-ProDOS.  This means it works just fine with
HardPressed on HFS volumes, but some of the items in the utilities menu don't
work as expected on ProDOS volumes.

(FYI, I've been booting into it throughout the development of HP, and I use
it to copy files around all the time... some things just aren't as transparent
under ProSel-16 as they should be.)

>  Yeah, can't say I've ever been in a position where I've needed the
>option list to be copied.

Here's a random fact I didn't know until recently.  The optionList is something
that the FST generates for you.  Under ProDOS, it works by copying it out of
a special area on disk.  Under HFS, it works by copying the stuff out of the
directory entry... the optionList is just the two four-byte type fields,
copied out of the HFS directory structure.

There is *NOT* a separate place on disk for an HFS optionList.  If you don't
"copy the optionList" on an HFS volume, you could end up losing information,
because the HFS FST has to translate the two four-byte types into a one-byte
filetype and a two-byte auxtype, and then translate those back into HFS
types... clearly there's room for loss.  If the file was created by GS/OS,
then it has types which can be translated readily, so in most cases it won't
matter if you ignore the optionList parameter.

If you don't believe me, try to make the optionList and file/auxtype say
different things.  Use the exerciser SetFileInfo, and then do a GetFileInfo
to see if your changes really happened.

To summarize: the optionList is a piece of data generated by the FST, not
stored on disk (except for ProDOS, which does weird things).

>		-Greg

-- 
fadden@uts.amdahl.com (Andy McFadden)
[ Above opinions are mine, Amdahl has nothing to do with them, etc, etc. ]