USB floppy drive for pc to convert MSX discs to DSK

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By Wild_Penguin

Hero (541)

Wild_Penguin's picture

11-03-2019, 00:18

I believe both of you guys might be right?

From linux's "ufiformat" man page:

Quote:

ufiformat supports only the following format capacities:

1440/1232/1200 (for 2HD disk)
720/640 (for 2DD disk)

The device should support the capacities also, otherwise ufiformat shows an error message.

The above format capacities are predefined in the program, but each USB floppy device also has a limited set of formats (defined internally) that it can format media to. The allowed format capacities are obtained by querying (-i) the device, but this only returns the total format capacity and not CHS (cylinder, heads and sectors), hence a mapping is required in the program.

On my computer, if HD disk inserted:

Quote:

$ sudo ufiformat -i /dev/sdg
vendor: TEAC
product: FD-05PUW
write protect: off
media type: 2HD
status block size kb
formatted 2880 512 1440
formattable 2880 512 1440
formattable 1232 1024 1232
formattable 2400 512 1200

But with SD disk inserted (actually, HD but with the hole covered):

Quote:

$ sudo ufiformat -i /dev/sdg
vendor: TEAC
product: FD-05PUW
write protect: on
media type: 2DD
status block size kb
formatted 1440 512 720
formattable 1440 512 720

But the man page hints that such drives could exist, which can support many different formats (but on Linux, officially only DS disks can be used - not sure about other OSes).

Also, IIRC - you can "cheat" and use SS disks by only using the first half (as a SS disk is "seen" as first half of a DS disk). I think this has been advised on this very forum, but I could have been dreaming ... or otherwise mistaken. Never used SS disks myself.

By Manuel

Ascended (15555)

Manuel's picture

11-03-2019, 07:37

zPasi wrote:

@rderooy
I have succesfully read ss floppies with an usb drive, explain that!

Which USB drive exactly and how did you do it?

By skumlerud

Resident (39)

skumlerud's picture

11-03-2019, 10:41

I have not been able to do that with my USB floppydrives. I have been able to write SS diskimages (using dd on Linux) on these by converting the diskimages to DS first.
I normally use my Atari Falcon to transfer files and diskimages to my MSX though, it's a lot less hassle as the Falcon handles SS disks just fine.

By konamiman

Paragon (1030)

konamiman's picture

11-03-2019, 11:50

Regarding 1DD disks, The Sony MPF82E (discontinued, but you can find used units in eBay) is able to read them with Rookie Drive and the FDD BIOS I developed recently - however you won't be able to read them in a Windows 10 machine, apparently the driver isn't designed for that. If you have a Rookie Drive you could read these disks and move their contents to 2DD disks.

As for "any USB FDD should be able to read 2DD disks" - don't bet on that, trust me :)

By skumlerud

Resident (39)

skumlerud's picture

11-03-2019, 12:00

Wild_Penguin wrote:

Also, IIRC - you can "cheat" and use SS disks by only using the first half (as a SS disk is "seen" as first half of a DS disk).

Not really. A disk image (atleast the ones I'm familiar with on the Atari ST and MSX) is usually just a dump of all tracks, starting from track 0. If the disk is double sided, side 0 is read first and then side 1. Then step to next track. So if you want to dump a SS image to a USB drive you first have to insert blank tracks between each track in the image.

The other way around is not so easy - if you have a real single sided disk there will be no formatting on side 1 and the drive will be unable to read it. It *may* (as in "I'm guessing, haven't actually tried this") work if you first format the disk as DS with your USB drive, then format it again as SS on your MSX. In that case there will be tracks on both sides and you may be able to dump it using your USB drive. Then remove the odd-numbered tracks from the resulting image, and you have a SS disk image.

By NYYRIKKI

Enlighted (5300)

NYYRIKKI's picture

11-03-2019, 19:14

skumlerud wrote:
Wild_Penguin wrote:

Also, IIRC - you can "cheat" and use SS disks by only using the first half (as a SS disk is "seen" as first half of a DS disk).

Not really. A disk image (atleast the ones I'm familiar with on the Atari ST and MSX) is usually just a dump of all tracks, starting from track 0. If the disk is double sided, side 0 is read first and then side 1. Then step to next track. So if you want to dump a SS image to a USB drive you first have to insert blank tracks between each track in the image.

The other way around is not so easy - if you have a real single sided disk there will be no formatting on side 1 and the drive will be unable to read it. It *may* (as in "I'm guessing, haven't actually tried this") work if you first format the disk as DS with your USB drive, then format it again as SS on your MSX. In that case there will be tracks on both sides and you may be able to dump it using your USB drive. Then remove the odd-numbered tracks from the resulting image, and you have a SS disk image.

You make this all sound very hard and like if we would really try to read everything while we only need to read the 1DD data... The trick goes like this... When you have 1440 logical sectors, you read first 9 logical sectors (that are on top side of disk) and then you SKIP the next 9 sectors (since they are likely broken if the disk has not ever been formatted from both sides or the other side is ie. HD formatted.) Then again when you start reading from logical sector 18 you are actually again on top side, but now track 1... Got the point? (Naturally this requires a software that selects the blocks to read like described. ) Exactly same idea works for writing, but the really uggly part is that doing it this way really requires that the USB FDC calculates the LBA wrong and in case some drive really does the calculation correctly then this method fails again.

By skumlerud

Resident (39)

skumlerud's picture

12-03-2019, 09:18

The problem is - atleast with my USB drives - that when I insert a real single sided disk (as in no format at all on side 1) the drive's firmware still attempts to read on side 1. When this fails it is not possible to read or write anything from the drive, all I can do is format it. Any regular read or write attempts to the block device fails.

I have not tried your way of writing a SS image to a USB drive, but it sounds like it should work. In my case the target disk would have to have been already formatted DS or the drive will not let me write to it. Personally I've found it easiest to insert blank tracks for side 1 in the image and then just dd it to a formatted DS disk. But even easier is to just use my Falcon and write the unmodified image directly.

By zPasi

Champion (367)

zPasi's picture

15-03-2019, 16:29

Manuel wrote:
zPasi wrote:

@rderooy
I have succesfully read ss floppies with an usb drive, explain that!

Which USB drive exactly and how did you do it?

A good question, but also a tough one Smile

My USB drive doesn't carry any brand name on it. "Made in China", maybe that helps Smile

And I don't remember which software I used and don't even use the same computer I used back then. It was a Mac and I used some program under Windows that I had under Vmware or Parallels.

Ok, I'll try to go and find out what on earth did I use! Wink

By Pencioner

Paladin (907)

Pencioner's picture

15-03-2019, 17:52

@zPasi you might look into device driver VID and PID (if you don't know what's it and it sounds too cryptic, google on "how to find device's VID PID") and then your nonamed model can be likely known from that info Smile

By Thom

Hero (546)

Thom's picture

20-04-2019, 20:13

I've bought the very cheap Gembird External USB 3.5" Floppy Disk Drive (FLD-USB-02). Although it says on the box it's not supporting 720 kB DD disks, it does. Although that might be because I'm using Lex Lechz's Disk-Manager. Haven't tried 360 kB disks yet.

So I went to my parents's attic with a large shovel and managed to find a lot of MSX floppy disks. I Hadn't seen them in decades. The first diskimage I've made contains a promo of the never released megademo 'Shockwave' by BCF. I still like the music in that promo and heard it for the first time since 1995 I think. It isn't on youtube yet?

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