Previous Thread
Next Thread
Print Thread
Page 3 of 4 1 2 3 4
Joined: Jun 2001
Posts: 465
O
Senior Member
Offline
Senior Member
O
Joined: Jun 2001
Posts: 465
You don't need posix level if you only read or write whole files. And in practice we already have the interface and implementation for a couple of filesystems. Some stuff could be added still, like defrag, but there's enough to try a first UI anyway.

Joined: Mar 2006
Posts: 1,060
Likes: 1
L
Very Senior Member
Offline
Very Senior Member
L
Joined: Mar 2006
Posts: 1,060
Likes: 1
could we get .dlt delta files holding a delta vs an actual floppy image? that way an original image isn't modified at all on disk, but the delta is applied to it on load if it exists in the same(?) directory as the image.


"When life gives you zombies... *CHA-CHIK!* ...you make zombie-ade!"
Joined: Mar 2001
Posts: 16,841
Likes: 45
R
Very Senior Member
Offline
Very Senior Member
R
Joined: Mar 2001
Posts: 16,841
Likes: 45
We have diff files like that for CHDs. They work great for fixed-original-image (arcade games and software lists), and are a bit of a nightmare for everything else.

Joined: Jun 2001
Posts: 465
O
Senior Member
Offline
Senior Member
O
Joined: Jun 2001
Posts: 465
Delta files are not really interesting for floppy images because they're too small for the delta to matter. Delta-like behaviour can be interesting (and is halfway-implemented, sorry), where mame "magically" remember the changes done to an image that is not actually changed, especially if it's in a zip.

Joined: May 2007
Posts: 566
Likes: 2
M
Senior Member
Offline
Senior Member
M
Joined: May 2007
Posts: 566
Likes: 2
Anything that can be turned on and off as desired is good for me.

Joined: Jan 2021
Posts: 69
=
Member
Offline
Member
=
Joined: Jan 2021
Posts: 69
Originally Posted by exidyboy
An educated guess could be made about which controller supported the original physical disks and synthetic images could be created using cpmtools against that format, but the resulting .DSK would not be a verbatim image of a disk that existed in the wild.

Such a synthetic disk image could also then presumably be marked BAD_DUMP as per your advice above.

With diskettes there definitely needs to be a 3rd marking to distinguish "bad" from "inaccurate" dumps, because areas outside the actual files often only matter for copy protected disks or bootblock position, so the indication should make it clear if the disk image does function or not.

With downloaded content or type-in listings from magazines the binary structure does not matter anyway, so there is no "master copy" to reproduce. Other diskettes often have bad blocks outside the actual files.

My main PC is a severely modded Highscreen Colani bigtower (DFI K6BV3+/66 mainboard with AMD K6-3+@550MHz, 768MB RAM, 2 genuine ISA soundcards, DVD writer, 160GB HDD, running Win98SE) which has a 1.44MB 3.5`` and 1.2MB 5.25`` diskette drive. Nowadays I have installed at its ceiling an additional modern ITX mainboard (Ryzen 2400G, 16GB RAM, 8TB HDD, DVD writer) for Linux Mint and Win10, so I first time have enough disk space to dump some 100 of my CDR (containing e.g. tons of downloaded ancient web pages about tech stuff etc.).

I am working through some hundred of my PC diskettes to preserve their contents. Some indeed were unreadable; particularly one brandless 1.44MB sort (black with white "HD" logo and too small paper sticker with cyan lines) tends to fail, and also 5.25`` things written with 360KB drives (ancient 286 and CPM machine at school) are partially unreadable. Often I have to carefully clean the surface with cotton swab and isopropanol (let it fully evaporate, else the surface is softened and gets scratched) and insert cleaning diskette with a drop of isopropanol between read attempts. Also rhythmically pressing the thumb on the front of the diskette can help to read bad blocks on warped disks. I had taken apart the external 3.5`` diskette drive of my IBM Thinkpad 760XD to rotate the head motor into different positions, which helped to recover a few more files.

(In former times my first PC was a 286 and later 386SX bridgeboard inside my very modified Amiga workstation (A500 in huge wooden case with handsoldered adapters, internal A570 CD drive, SCSI card for Iomega 20MB sort-of diskette drive etc.). At hat time I had often manually adjusted diskette heads because school diskette drives all seemed to be misaligned or dirty and so wrote incompatible diskettes, which e.g. made it hard to use downloaded files (through DOS ftp at school, had no internet at home). Thus many of my diskettes seem even worse misadjusted than original payware or shareware ones.)

For reading, I yet have only DOS mode of Win98SE for file copy (unlike windoze it allows infinite retries), a primitive track reading program disktool.exe and procopy.exe to mage binary images and check which blocks are unreadable. Bad with these tools is that they tend to replace unreadable tracks with random copies of previous tracks (likely garbage from a ring buffer), which makes them hard to identify in a hex editor (e.g. to merge multiple bad dumps).

I e.g. still have some unreadable 360K 5.25 CPM/86 disks from my practical course, those were likely written on a Siemens PG675(?) industrial computer (resembling an Osborne PC with internal green CRT), which was used to program Simatic PLC hardware.

https://forums.bannister.org/ubbthreads.php?ubb=showflat&Number=106592

[Linked Image from i.imgur.com]

https://forum.classic-computing.de/forum/index.php?thread/15021-siemens-pg675/
https://en.wikipedia.org/wiki/Simatic
https://de.wikipedia.org/wiki/Simatic

The crazy thing is that there were some games on this computer. E.g. there was a textmode clone of "Qix", of "Centipede", of "Nibbler" and of "Ork Attack" (?, you had to move left & right to defend a castle by dropping stones on enemies those built ladders to climb up a brick wall); the latter even used a redefined charset but AFAIK none of them had sound. And I think I had copied them on my floppy.

My dump with disktool shows in HxD fragments of recognizeable words (e.g. file names) but likely nothing complete. At secondary school we also had on Commodore 286ers a CNC turning lathe and milling machine simulator (terrible DOS program that crashed with "division by zero" when moving the tool out of range), of which I still have diskettes with the code I wrote. But the disk with compiled code (for an actual Heidenhain milling machine?) is unreadable like when the disk wobbles eccentric and so only reads half of each track. But I guess it is the different head geometry that makes the Mitsumi 1.2MB drive of my Colani bigtower fail to read it.

Reading strange 5.25 floppies?

Is there a program to read 360K (or lower?) DOS or CPM floppies in an Atari XL or Commodore C64 floppy drive, to convert it into a PC readable format? Eons ago I used a DOS serial port adapter (SIO2PC) to communicate with Atari 800XL and C64 to read and write their disks. Else I likely need a 360k PC drive. In a box of old parts I somewhere had a belt-driven double-height 5.25 drive full of DIL ICs (found in fleamarket scrap in 1990th) but I doubt that it works and have no clue what connector it uses and if it ever could be connected with PC hardware. It may have been gutted out of an Apple II or such.

Last edited by =CO=Windler; 08/24/21 03:22 AM.

MAY THE SOFTWARE BE WITH YOU!

{weltenschule.de}
Joined: Mar 2001
Posts: 16,841
Likes: 45
R
Very Senior Member
Offline
Very Senior Member
R
Joined: Mar 2001
Posts: 16,841
Likes: 45
360K PC disks are double-sided, which Atari and Commodore drives are not.

Joined: Apr 2005
Posts: 589
Senior Member
Offline
Senior Member
Joined: Apr 2005
Posts: 589
The Commodore 1571 disk drive is technically able to read double-sided DOS or CP/M floppies (at least from what I've read, I still don't have one myself), but there is no dumping software for the C64/C128 that I know of.

Also, you might probably have better results if you dump the floppies with one of the sophisticated dumping devices like a KryoFlux, FluxEngine, SCP or similar. I have dumped dozens, if not hundreds of old 360K disks and have not come across one that at least one of my two 5.25 HD drives could read. I'm having more trouble with old 3.5'' HD floppies to be honest...

Last edited by Darkstar; 08/24/21 10:01 AM.
Joined: Jan 2021
Posts: 69
=
Member
Offline
Member
=
Joined: Jan 2021
Posts: 69
But with 360k 5.25 diskettes AFAIK a 1.2MB drive is often incompatible due to different magnetic field geometry. It may even be that I have a Commodore 1571 somewhere in my parent`s house (in another city). Kryoflux seems quite expensive. But I am still daily using my Amiga and own a lot of other homecomputer diskettes, so something like Kryoflux might be useful, if it can convert the resulting image file. (AFAIK its native format is a kind of 50MB WAV file sampled of each track that can be only written back to diskettes but not used in emulators.)


MAY THE SOFTWARE BE WITH YOU!

{weltenschule.de}
Joined: Feb 2004
Posts: 2,291
Likes: 19
Very Senior Member
Offline
Very Senior Member
Joined: Feb 2004
Posts: 2,291
Likes: 19
1.2MB drives can work in DD or HD mode – it’s software selectable. The disk will be ruined and need degaussing if you try to format it in the wrong mode, but the drives support both.

Page 3 of 4 1 2 3 4

Link Copied to Clipboard
Who's Online Now
0 members (), 19 guests, and 2 robots.
Key: Admin, Global Mod, Mod
ShoutChat
Comment Guidelines: Do post respectful and insightful comments. Don't flame, hate, spam.
Forum Statistics
Forums9
Topics8,993
Posts118,153
Members5,005
Most Online890
Jan 17th, 2020
Forum Host
These forums are hosted by www.retrogamesformac.com
Forum hosted by www.retrogamesformac.com