Interest in a DiscFerret?
Fred Cisin
cisin at xenosoft.com
Wed Jan 9 21:34:43 CST 2019
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
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