====================
1. EXE Functionality
====================
I've found this little 1989 utility being capable
of editing a FAT32 hard disk under Windows 98, at
least regardsing the EXE file that came along.

Here's an example screen printout of a BLANK
hard disk sector, as it would appear at runtime.
NOTE: it DOES actually work for sectors WITH data
in them; this is just an example of the GUI:

                            Laine's Mighty Disk Editor  v0.0 02/13/89
?????
??1 0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  Fo0123456789ABCDEFo
??1
o00o00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00o................o
o01o00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00o................o
o02o00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00o................o
o03o00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00o................o
o04o00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00o................o
o05o00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00o................o
o06o00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00o................o
o07o00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00o................o
o08o00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00o................o
o09o00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00o................o
o0Ao00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00o................o
o0Bo00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00o................o
o0Co00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00o................o
o0Do00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00o................o
o0Eo00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00o................o
o0Fo00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00o................o
?
PgUp/PgDn - Prev/Next Sector,  F10 Updates Sector
(alt+F10 enables update)
G - Goto Sec, M - Modify byte,
R/W - Read/Write Sec to/from File, ESC to quit

========================
2. Attempted Compilation
========================
However, the author said that its source code
(see below) was tested on Turbo C++ v1.5 and
Zortech, yet I could NOT compile it with a
Turbo C++ v3.0, which I suppose should have
been backward compatible with
Turbo C++ v1.5 ?
It kept complaining about all sorts of missing
variable declarations that WERE nicely declared
within its various "include" files.

=====================================
3. Code Rearrangement for Compilation
=====================================
So, what I did was, I took all "define" and
declaration statements out of the "include"
files and put them, along with all functions
and other code, into a single file I called
"edit_2.c" that I created especially for that.

=================================
4. Compile Successful: Now What ?
=================================
Surprisingly enough it all compiled (using
Turbo C++ v3.0) and a nice EXE was produced.
However when I ran it, nothing happened - seemed
like I should have called various functions
myself - as there was no "main()" function at
all.

================
5. Advice Needed
================
Could anyone be kind and please take a look at
the code - and tell me exactly what I should add
to it in order to make it perform its intended
purpose ?

Appreciate any help,
Thanks a lot,
Dan Richardson

NOTE: both original and modified source code listings
      will follow this post.

I'd leave this well alone if I were you. There are much better ways of
learning C

Before you hack on this code, it would be a really good idea to
completely understand what you're doing (and your post indicates
that you may not.)

You've posted enough code for force most who want to help you to
spend /hours/ of effort on your behalf. That's not necessarily a
bad thing of itself, but it seriously reduces the number of
people who'll be willing to help...

Unless I'm mistaken, in 1989, there was no such thing as FAT32, and
even now there are FAT32 file-systems or partitions, not FAT32 disks.

Such subtleties should be respected by anyone intending to write
directly to the "raw disk" (in which case FAT32 is meaningless anyway)

Playing with fire...

Hi All,

I appreciate the quick responses (even though not
yet technically specific, as I would later hope).

--------------------------------------------------

1. For all those worrying about my
   "beginnerness" - please be advised
   as to the following:

   1.1. I've had as yet a little bit of
        experience in the computer field - well
        over 10 years :-)

   1.2. About the same goes for my knowledge
        of various programming langauges -
        such as ASM, Basic, Pascal.

   1.3. Everything I care about, data-wise, is
        backed up in multiple copies :-)

   1.4. My system configuration (including all
        software installations and the like) is
        also backud up.

   1.5. So, as one may figure out, I would NOT
        be afraid of messing around with my
        machine whatsoever...

   1.6. I hope now that everybody's
        rest assured :-)

--------------------------------------------------

2. To Morris: your advice about asking 'smaller'
   was indeed an excellent one. I'll stick to it
   from now on, as much as I can, and NOT pour in
   a whole bunch of code lines; instead, I will
   do my best to explain the things I want to do
   in plain English.

--------------------------------------------------

3. Basically, my problem is very simple:

   3.1. I need to be able to read/write absolute
        sectors of whichever drive on my
        machine - being a floppy, hard/fixed,
        CDROM or even a RamDisk.

   3.2. Having looked at Turbo C++ v3.0's
        online help system, it seemed like
        there are two (2) functions that
        were designed for that purpose:
        - absread
        - abswrite

   3.3. Unfortunately, when I copied their
        example and tried specifying "0x80"
        as the "Drive" (for the hard disk),
        having run the "absread" code gave
        me a "Disk Problem" error.

   3.4. I tried to look at some other stuff
        within the online help system, and
        found two (2) other functions:
        - "biosdisk"
        - "_bios_disk"

   3.5. Unfortunately, the examples for THOSE
        functions showed all kinds of interrupts
        OTHER than "Int 25" and "Int 26" (which
        are used for "absread/abswrite" stuff)
        which, again, wasn't much help either.

--------------------------------------------------

4. Therefore, would anyone please tell me how to
   do the following?

   4.1. A "read/write" of absolute sectors -
        ESPECIALLY on a hard disk; please note
        that the 1989 utility worked WELL on my
        FAT32. I even saved, erased, and then
        successfully restored critical data
        from sectors, such as the bootstrap
        and portions of the FAT.

   4.2. Is there code anywhere for reliably
        identifying all drives on a system ?
      - Regardless if I booted from a floppy
        or opened a DOS box ?

   4.3. How could I use "Int 13" - which seems
        to be what the 1989 utility uses -
        instead of "Int 25" or "Int 26" ?

        * Also, please keep in mind that:

        4.3.1. I don't have all too much
               knowledge about using interrupts
               in general;

        4.3.2. I've programmed in C very little;

        4.3.3. Should ASM code become necessary,
               I'd really like to use it either
               inline (as a "wrapper" function)
               or as a linkable OBJ code/file.

--------------------------------------------------

I hope I've been clearer now about what it is
I want to be able to accomplish, regarding
that 1989 utility: I want to duplicate its
functionality, which I can do only if am
able to "read/write" absolute sectors.

For all good people who wish to help - thank you!

I think you'll need to pursue X86 and DOS-ish aspects of this
problem in newsgroups with those interests - comp.lang.c tries
(more or less successfully) to maintain a focus on the portable
standard C programming language. I'm aware that these other
newsgroups exist; but not the group names. Perhaps someone who
/does/ know would be willing to redirect?.

I'm not sure how to even approach the 'identify all drives'
problem. This could be a significant piece of work. There are so
many ways of attaching drives (SCSI, USB, Firewire, ad quasi
infinitum) that you might want to lower your sights just a bit
for the /initial/ implementation - unless this is resolved for
you by standard BIOS calls.

1. I will definitely redirect my question(s) to some
   other, more suitable groups.

2. To Morris: thanks for being so nice!

3. To all flamethrowers: you could be slightly nicer,
   don't you think? Good manners won't hurt you.
   All I wanted to do is ask a question about some
   topics that I don't know much about (as some of
   you have so unpleasantly mentioned). I really
   was asking for help, and if someone came up to
   me with ANY no-nonsense quetsion, I'd help that
   person right away!

It's only because most of the regulars here are sincerely
interested in C, that they're are also interested in topicality.
Compared to this newsgroup, most others are zoos.

[...]

   What you need is:

1) A good reference of DOS/BIOS interrupts. Look in
http://www.google.com for "Ralph Brown's Interrupt List" or "HelpPC".

2) Understanding of how disks work on low level

3) Interface to assembly language of your complier - check its
reference manual

The right groups for this topic are: