1DD floppy drive questions

Master (137)

04-06-2023, 02:49

Hello all
I have recently bought a Sanyo MPC-25FS and I have some questions about the 1DD floppy drive:
- Do I need to use 1DD floppies or is the drive able to format a 2DD floppy to 360Kb? When I try to do this, the format process seems to go through but right at the end it errors out.
- Would the drive be able to read a 2DD floppy at all? When I try FILES on any floppy I have (these are all 2DD) I can hear some noise but it errors out.

I am basically trying to figure out if it is worth it for me to go after a 1DD floppy (these are hard to find and not cheal) or if the drive is malfunctioning. If it is malfunctioning, I guess I could replace it with another 1DD from a Philips computer right? I assume I cannot simple install a 2DD drive. Maybe I am wrong?

Thanks

By cjs

Master (143)

04-06-2023, 03:54

pmack wrote:

I have recently bought a Sanyo MPC-25FS and I have some questions about the 1DD floppy drive:
- Do I need to use 1DD floppies or is the drive able to format a 2DD floppy to 360Kb?

You can use double-sided diskettes. A "single-sided" diskette's only difference from double-sided is that the second side is not guaranteed to be error free (but it usually is). A single-sided drive (or a double-sided drive, for that matter) has no idea whether it's using a single-sided diskette.

Also note that, except for the number of sides that are verified to work, there's no difference between any of the double-density diskettes. 2D and 2DD refer to the drives (40 track or 80 track), but the media is exactly the same, whether labeled "2D" or "2DD."

Quote:

When I try to do this, the format process seems to go through but right at the end it errors out.

Sounds like it's a bad diskette. A less likely possibility is a broken drive.

Quote:

Would the drive be able to read a 2DD floppy at all?

Yes, but it will be able to read only one side of it, which might be very confusing to the computer, depending on the file system. I don't recall now if the MSX filesystem needs to be able to read both sides of the diskette to read the directory (and FAT?), but I'm sure someone else here will know. (Oh, and I'm assuming here that you're using a diskette that's been formatted on another machine with a 2D or 2DD drive and reads successfully there.)

Quote:

I am basically trying to figure out if it is worth it for me to go after a 1DD floppy....

No; a single-sided diskette will be, for your drive, no different from a double-sided floppy. (1D, 1DD, 2D, 2DD, all the same to it.)

It is, however, worth getting some diskettes from another source (or maybe two different ones) to verify that the media you currently have isn't a bad diskette or even a bad batch.

Quote:

If it is malfunctioning, I guess I could replace it with another 1DD from a Philips computer right? I assume I cannot simple install a 2DD drive. Maybe I am wrong?

You can almost certainly install a 2DD drive and have it work, though it will probably work only in single-sided mode, as a 1DD drive. Though that does depend on the code driving it.

By mars2000you

Enlighted (6559)

04-06-2023, 04:19

cjs wrote:

pmack wrote:

I have recently bought a Sanyo MPC-25FS and I have some questions about the 1DD floppy drive:
- Do I need to use 1DD floppies or is the drive able to format a 2DD floppy to 360Kb?

Unfortunaly, it's not true for the 4 versions of the MPC-25, as indicated in the Wki:

"Four different versions were released. Note that these computers can only format in the mentioned format due to how their disk ROMs work:"

https://www.msx.org/wiki/Sanyo_MPC-25FS

In other words, you need to change the Disk ROM on these computers!

By sdsnatcher73

Enlighted (4298)

04-06-2023, 06:14

cjs is correct here, the MPC-25FS will be able to use all 1D, 1DD, 2D and 2DD 3.5” floppies but it will only be able to format it to a 360kB (1DD standard). This is due to the combination of disk ROM and the disk drive used. Replacing the disk drive with a 2DD model is possible but to be able to format it as 720kB you need to change the disk ROM as well.

Apart from a bad disk or a broken diskdrive, the drive may just require some cleaning of the head (with a cleaning disk) or possibly a more thorough cleaning by dismantling the drive.

I have 2 MPC-25FS’s as well. One was modified with a Mitsumi 2DD drive from a Philips NMS8250 (the bezel of the original drive can then be used on the 2DD drive).

By cjs

Master (143)

04-06-2023, 07:34

mars2000you wrote:

"Four different versions were released. Note that these computers can only format in the mentioned format due to how their disk ROMs work:"

sdsnatcher got it, but just to make sure everything's clear, there are three different things we're talking about here. These apply to both 5.25" and 3.5" drives, as the latter are basically slightly smaller versions of the former.

1. Media, the floppy diskettes themselves. There are only two types of coatings: high density ("HD," used for 1.44 MB and similar) and standard density. The latter is usually called "double density" and may be one or two sided.

2. Drives. These are 40- or 80-track (the former are rare in 3.5" drives, but common in 5.25" drives) and one- or two-sided. Again, there are only two actual flux densities, HD and standard density. "Single density" and "double density" are not attributes of the drive but how the controller encodes the data: FM or MFM (the latter basically offering more compression). 80-track drives are sometimes called "quad density" but the flux density is the same as a 40-track drive; there are just more, narrower tracks on the diskette. The Japanese usually call single- and double-sided 40-track drives "1D" and "2D," and 80-track drives "1DD" and "2DD," but this is not common outside of Japan. All standard-density drives use the same media, regardless of number of heads or tracks, with the exception that if you use a single-sided diskette in a double-sided drive you may find that the unqualified second side gives you errors. (Often it's just fine, though.)

3. Controllers. The controller and the code running it determine what formats may be used, including whether the you can use all 80 tracks or just 40 tracks of an 80-track drive, whether you can use the second side on a double-sided drive, and so on.

If you really want to get into it, I have further notes here. But the key is mainly just to remember "HD or standard density; two sides or one; 80 tracks or 40."

By Briqunullus

Paladin (769)

04-06-2023, 10:11

On a double sided disk, the data is written on alternating sides. The first sectors on the disk are reserved for system data, and yes, these are partly written on the other side as well. That's why a double sided disk will not be readable on a single sided drive.

By pmack

Master (137)

04-06-2023, 19:09

Thanks everyone for the responses. I tried another disk and it is definitely not working so it has to be the drive. It looks like you need to remove the top board to be able to remove the drive from the computer (terrible design). If the drive does not work after cleaning, do you have any suggestions as far as where I could get a replacement?