Improve Floppy Controller

[chschnell]

I'm currently working on floppy.js, the issues I'm aiming to fix:

• add floppy controller support for various guest OSes:
  • Windows 98 floppy disk support #1003
  • Windows 2000 floppy disk support #1063
  • Issues with Win2k3 #1358
• add floppy images to state snapshots:
  • Floppy disk buffer changes are not saved or loaded with the state #1050
• support second floppy drive fdb
• support format command to allow blank floppy disks

In the past weeks, whenever I found a few hours here and there, I've been reading through floppy.js, the qemu implementation fdc.c which I use as reference, and whatever I could find on the Internet about the Intel 82078 Floppy Disk Controller which qemu implements.

So far I've added a bunch of boilerplate code to floppy.js and split off a new class FloppyDrive from FloppyController to allow for multiple drives, and similar to what I did with the IDE controller, I've refactored many literal constants to named constants and improved logging.

It's still too early for a PR, but are there any other known issues around the Floppy Disk Controller?

[chschnell]

I now have floppy support for Windows Server 2003 (issue #1358):

To get this to work I had to rewrite large parts of floppy.js (there was a lot of skeleton code), the Windows 2k3 (NT kernel) is quite sophisticated here.

I ran make all-tests and manually tested these guest OSes so far (all tests passed):

• MS-DOS 6.22
• FreeDOS 1.4
• Windows 3.1
• Windows 95
• Windows 2k3
• Debian 12

All guests (except Win31 which was booted from FDA) were booted from HDA and the floppy disk was inserted into the drive after boot.

There's going to be a breaking change for v86 state snapshot images where the floppy controller was snapshotted in non-idle state, meaning when it was in the middle of executing a floppy command. The runtime states differ too much in this case to map from the old snapshot representation to the one I need in the new representation. Maybe that's not a big deal, I don't know.

[chschnell]

Branch: https://github.com/chschnell/v86/tree/fix-fdc
You can test it at: https://www.rekoba.de/~cs/v86/demo/

I can't find any Win98 or Win2000 images for v86 to download, I'd really like to test them. Should I build them myself? Or maybe someone has some links?

[copy]

I can't find any Win98 or Win2000 images for v86 to download, I'd really like to test them. Should I build them myself? Or maybe someone has some links?

Here you go: copy.sh/tmp/windows2k-v2.img.zst copy.sh/tmp/windows98.img.zst

[chschnell]

I can't find any Win98 or Win2000 images for v86 to download, I'd really like to test them. Should I build them myself? Or maybe someone has some links?

Here you go: copy.sh/tmp/windows2k-v2.img.zst copy.sh/tmp/windows98.img.zst

Perfect, thanks!

Only Windows 98 seems a bit unstable here, anything special to consider regarding RAM/BIOS/ACPI settings? EDIT: never mind, works now.

[chschnell]

Lookie, lookie: fdb!

Debian 12:

root@debian:~# lsblk
NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
fd0      2:0    1    4K  0 disk
fd1      2:1    1    4K  0 disk
sda      8:0    0    2G  0 disk
└─sda1   8:1    0    2G  0 part /
sr0     11:0    1 1024M  0 rom

Windows Server 2003:

Windows 2000:

NOTE: The window on the upper left shows drive B:, and the one on the lower right shows that the floppy controller support for Windows 2000 is fixed (issue #1063).

EDIT: Windows 98:

NOTE: I had to run Add new Hardware from the control panel to add drive B:. This also shows that the floppy controller support for Windows 98 is fixed (issue #1003).

EDIT 2: Windows 1.01:

[chschnell]

Added insert/eject fdb into the user interface of my demo, here's w2k3 with both fda and fdb loaded (floppy disks are FreeDOS1.4 and Windows1.01, respectively):

[DressedAlarm184]

@chschnell I've been using a fork of your v86 repo to enable the CI action to test the floppy drive B support in my private Windows 2.03 emulator. Your "further code cleanup" commit results in an error when building.

EDIT 1: Still doesn't build (same error too) with the newest "added support for floppy disk formatting" commit too

[chschnell]

@chschnell I've been using a fork of your v86 repo to enable the CI action to test the floppy drive B support in my private Windows 2.03 emulator. Your "further code cleanup" commit results in an error when building.

EDIT 1: Still doesn't build (same error too) with the newest "added support for floppy disk formatting" commit too

@DressedAlarm184: Thanks for reporting, I've fixed this bug in the latest commit and make all-tests now runs fine again here.

[chschnell]

Formatting floppies seems to work now.

So far I've tested with FreeDOS 1.4 (format a:), Debian 12 (mkfs.msdos /dev/fd0) and Windows Server 2003 (through the GUI, tested both Quick format and Full format because they work a bit differently).

I can use an unformatted, blank floppy disk image file when formatting, so a create empty disk function could be added now to the v86 web UI similar to the hard disks.

For a demo, here's a full format of a 1.44M disk (FreeDOS boot disk) under Windows Server 2003:

w2k3-format-fda.mp4

[chschnell]

@DressedAlarm184: branch chschnell/v86:fix-fdc that you forked off is now stale and will not receive further updates, please move to new branch chschnell/fix-floppy-controller. I'd like to delete the old branch.

[DressedAlarm184]

@chschnell Okay, I have renamed the fix-fdc branch to fix-floppy-controller.

[PTz0uAH]

@chschnell I tested the changed Floppy.js with latest v86 and my Win98se image and must say "It works!"..

but the floppydrives still work under msdos compatibility mode and device manager ignores them..

any ideas how to get Devicemanager showing those drives?

[chschnell]

any ideas how to get Devicemanager showing those drives?

Did you see my remark where I posted about Win98 SE:

EDIT: Windows 98:

NOTE: I had to run Add new Hardware from the control panel to add drive B:. This also shows that the floppy controller support for Windows 98 is fixed (issue #1003).

You might also just try hitting Refresh in the device manager, or try to reboot (that was neccessary under W2k to get rid of all glitches).

[PTz0uAH]

@chschnell it's great those floppy drives are working now.. superb!

Couldn't test it on your demo site though (not working)..

So I had to build an experimental version.. and test it overhere on the local wasm-enabled "tinyweb" server..

Furthermore after the "on-device-installed-like-a-breeze" Win2K3 I also succeeded in installing Win98SE right in v86..

The "on-v86-device" installation was absorbing a lot of time and even brought back the memories of how frustrating it was back in the day sometimes with dodgy hardware.. using the right bootfloppy and specific params was the key.. win98/setup /C /ie /iv and trying to install otherwise failed 100% of the time..

Nevertheless I succeeded, albeit conquering those BSODs is not for the normal end-user.. so a step by step manual that works for everyone is not possible yet.. there are too many factors involved.. therefore one has to be very lucky indeed.. :-)

Now I understand also why using QEMU is adviced.. as a workaround for some of the hardware quirks of v86..

Nevertheless I always prefer a local install.. yet the rate of success with Win9x highly depends on the machine and browser (i7 32gb + latest Chrome on Win10 64bit gave best results for me)..

I also tested the ramdisk-B:-dependable XP+ PE "hobby" builds and those are showing also 2 floppydrives available and while the Ramdisk is correctly getting the B: letter assigned the FDB is pushed forward in the enumeration.. so got C: (plus removable drive) assigned to it in a hdd-less live-cd setup..

As a workaround I disabled the B: drive in floppy.js and now I thought I could work with it the way I like it.. but now Win98SE hangs..

You already provided the hints in the code so I just used new FloppyDrive(this, 1, fdc_config?.fdb, fdb_image, CMOS_FDD_TYPE_NO_DRIVE) and that worked seemingly fine for my experimental fork to disable FDB.. but now I cannot use A: anymore.. it shows the content and freezes.. so I guess I did something wrong and more FDB code needs to be disabled probably but for now I revert to the "working version"..

BTW with nothing disabled in your floppy.js the drive A: works fine but one thing that would be rather handy.. (if changed..autosave when eject?).. if booting v86 without floppy and later insert a disk.. I could write to it yet not save the fdd-image for there is no "get floppy" button.. or can I perhaps use some JS code to save the disk anyway?

"Thanks and keep up the good work!"