Interest in a DiscFerret?

[Fred Cisin]

On Thu, 10 Jan 2019, Guy Dunphy via cctalk wrote:
> Has anyone used a DiscFerret, to actually extract files from say, Apple II disks
> and HP LIF disks?
> The website- https://discferret.com/wiki/DiscFerret
> It seemms like the project is dead since 2013, was only ever for Linux, and never included software
> that understands various old floppy formats. Is that right?
> My neads (using DOS, WinXP or Win7) are:
> * At the moment I'm attempting to restore my old, heavily modified  Apple II to working condition,
>  and then archive all my old Apple II files on floppies to PC. Part of a project to document a
>  bunch of projects I did in my 20s, 1970s t0 1980s.
>  The intro article is here: http://everist.org/NobLog/20181001_missing_wave.htm
>  Another article is in progress, about the restoration and doco of all the mods I did on my Apple II.
>  After it's working and old files extracted, then an article about my hacking Apple DOS 3.2 to
>  get higher data density. The old thermal printer listings are faded to illegibility, so I'm
>  really hoping the floppies are still readable.
> * Also I have some old HP equipment that uses HP-format floppies. LIF? They're not DOS compatible.
>  A HP 1630G logic analyzer with 9121 GPIB dual floppy drive, and a HP 80000 data generator.
>  For both machines I have old floppies containing critical  utilities (including a bunch of
>  disassembly utilities for early processors) that I really want to back up on PC and put online.
> There's sentimental and historical interest with both, and practical need with the HP gear.
> But, I have little experience with data recovery from old floppies. Long ago I did have a PC ISA
> bus card for extracting bit transition images from floppies, but I can't find it.
> Just now starting to look for what's available. Hoping for something that just works, as I have
> way too many projects already.
> I do have boxes of old drives, 8" 5.25" and 3.5", most densities.
> What other all-formats floppy R/W and data recovery tools do people here know of?
> Comments of their functionality?

A couple of questions to discuss.  Believe it or not, they are not 
rhetorical questions.

1) Do you like to re-invent the wheel?
You CAN make a better one, and have fun doing it.

2) Do you want to image the disks, for later recreation of a duplicate 
disk?
OR
3) Do you want to extract FILES?  (to be viewed/edited/used on PC)

The majority of the flux-transition products were developed around #2.
I don't know which, if any, ever completed the software for #3.

#2 and #3 are actually not mutually incompatible.
If you make images of the raw content of the disks, you could work from 
those images, rather than from the physical format on the disks themselves 
for extracting files.  That is especially an issue for formats such as 
Apple2, which can not be read by stock PC hardware.  And, if you succeed 
in creating a 140K file of the bytes on an Apple disk, then you do not 
need to worry about whether it will survive any more read attempts.

For example, David Small's "Magic Sac" Macintosh emulator originally used 
MFM images of Macintosh GCR disks.  Not his first choice for a name for 
it, but that was as close as Apple's lawyers would let him get.  Later, he 
created "Spectre GCR" to be able to read the Mac GCR disks.

If you can image the Apple disks, so that you can wade through the raw 
content on a PC, the details of the raw physical format, the logical 
format, and the file system are documented.  MOST of that is present in 
"Beneath Apple DOS".
With the GCR structure (they changed it between DOS 3.2 and 3.3) you can 
convert, and extract the bytes, to get 13 or 16 256 byte sectors per 
track.
You then need to look at the data structures of the Directory (track 17?) 
to figure out which sectors comprise each file.
Apple DOS, PRO-DOS, P-System, and Apple CP/M each have different data 
structures for their directories.
About 30 years ago, I wrote the software to extract and copy files from 
those formats on Apple disks, using a board [made by somebody else] in a 
PC. ("Apple Turnover", later just "Turnover" when Apple's lawyers spoke 
up).  The publisher and vendor of the product screwed both of us.

The majority, but far from all, of the other formats use MFM, with a track 
structure that is compatible with the NEC and WD track format.  Most, but 
not all of those can be done using PC hardware.  (Some, such as FM/"Single 
Density" and 128 bytes per sector, can be done on some PCs and not others)

Apple's GCR (it is NOT MFM) is different between AppleDos 3.2 and 3.3, and 
is different from the GCR used by Commodore, Sirius/Victor, and some 
others.

Some file system data structures, such as CP/M, TRS-DOS, P-system are 
documented.  Some are not.    Some claim to be documented, by telling you 
sectors per track, bytes per sector, and what track the dirctory is on, 
but not the data structures of it.


Oh, yes.  and, . . . 
4) You will need to write additional code to work with the content of 
those files if you want to load word processor or spreadsheet files into 
any of the "modern" office programs.  Word processors, even Wordstar, did 
NOT store the documents as ASCII text.


I wrote XenoCopy, but it is NOT STILL AVAILABLE and I got out of that 
aspect a few decades ago, so I remember some details, but not all of the 
really important ones.  At the time, I estimated that there were about 
2500 different floppy disk formats, and I implemented 400 of them.

Chuck did 22Disk (Sydex).  He seems to have stayed involved, had greater 
mastery, and remembers much more than I do.

--
Grumpy Ol' Fred     		cisin at xenosoft.com
http://www.xenosoft.com