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From: hatcher@INGRES.BERKELEY.EDU.UUCP
Newsgroups: comp.sys.amiga
Subject: Re: Further file format problems
Message-ID: <8705280817.AA02563@ingres.Berkeley.EDU>
Date: Thu, 28-May-87 04:17:27 EDT
Article-I.D.: ingres.8705280817.AA02563
Posted: Thu May 28 04:17:27 1987
Date-Received: Fri, 29-May-87 05:29:04 EDT
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In article <154@l5comp.UUCP> scotty@l5comp.UUCP (Scott Turner) writes:
>Summary: File identification is out of your worst nightmares.

Not really. Just a question of learning the machine. I have completed my
project, the "filetype" program. Tells you what any given file is; very
handy for browsing, since by default it sorts by file type. This was
inspired by the Unix "file" program, which I sorely missed having on my
Amiga. It does very well indeed at identifying most any file you'd ever
think about aiming it at, including English versus C versus Mail etc, as
well as *all* the hairy binary files. I got lazy when it came to recognizing
Pascal, Fortran, Basic, and assembly source, but those are the only things
left to do that I could think of. However, it takes up 23K using Lattice,
and there is still a global variable used, so I may rewrite it. [ Did you
know that Flight simulator uses the digits of pi, rounded off, and transposed
into hexadecimal, as a magic number on its magic executables? Not that anyone
cares...I'll probably remove that one feature...]

>  ...     Be aware when digging through raw hunk data that this data can in
>many cases change in value due to it's being patched by the relocater after
>it gets loaded.

Thanks, I'll check it out. And thanks for your other purely informative
comments.

>>	Finally, I can't find any method for distinguishing handlers from
>>	regular executables at all. Anyone know how?
>And finally we get down to the $64,000 answer. You RTFM that came with the
>product. Which is why it's handy to get a FM in the first place.

On the one hand I appreciate technical assistence, and answers to my questions.
On the other hand, this seems like a pretty rude comment to me. And it
doesn't answer the question, either. Fortunately I figured it out from hex
dumps already, and tomorrow I will read the AmigaDos Technical Reference
Manual...somehow I missed this one buried in the back of my Bantam book.
FYI it did *not* come with the product.

Half the problem in learning a subject is figuring out exactly where to
look for the answers. Looking in the wrong place can make it seem like
something is undocumented. However, before asking my question, I had
already consulted the 4-volume Addison Wesley RKM, Programmers Guide to
the Amiga, Amiga Developers Manual, AmigaDos Users Manual, the Amiga
Programmers Handbook, all of my Lattice include files, and spent hours
and hours poring over hex dumps. Personally I think that this qualifies as
Reading the F.M., so I felt free to ask the net for further help.

Perhaps I'm out of line here; maybe I shouldn't ask any questions until
I'm already an expert on AmigaDos. I didn't realize that was the policy here
(at least since Scotty joined us).

>Yeah, I for one don't put in the moveq rts mumbo jumbo. It isn't required and
>if a user executes my code instead of using as I DOCUMENT well Mr. Guru will
>keep the world from imploding. :)

I for one wish that people would be a little less smug about allowing gurus
to happen. I suppose it really makes *your* day every time a guru shows up?
And you're really unhappy with programs that refuse to guru no matter what?
And ashamed if you write a program that is robust?

And before I go, I'd like to ask you to aim your flames more carefully
when you're complaining about AmigaDo*...some of them are hitting CATS
people like Andy Finkel, and it is hardly his fault that the system is
the way it is. The problems exist for historical reasons that you are probably
very familiar with, and now we all get to live with them. The CATS people
probably hate the problems worse than we do, since it is their job to
help people understand and work around them. Give them all a break...
let them know you appreciate them being here on the net answering questions.
People who flame CATS tend to be unpopular with a large audience. And
I think Andy deserves a medal for such remarkably calm, informative responses
to Scotty's flames.
	Doug Merritt		ucbvax!ingres!hatcher       (for Keith :-)
				hatcher@ingres.BERKELEY.EDU (for Bryce :-)