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SomeGuy
October 20th, 2013, 11:34 AM
Another surprise from my local Microcenter: They had a new, different batch of USB floppy drives on the shelf. On the back of the box they said they support 720k disks! I know that there have been some out there that can do this, but it seems hard to nail down a good source for these.

So I grabbed one and tested it out. Sure enough, right out of the box it could read and write standard DOS formatted 1.44mb and 720k disks! From DOS, at least on the machine I used without any additional drivers, it ignored the low-level command and only verified the disk when formatting. Windows XP format doesn't know what to do with 720k disks from the GUI, but from the command line it seemed to low-level format a blank 720k disk just fine. I verified that the disk was readable in a normal drive.

Another surprise was when I fed it a 1.7mb (21 sector) formatted disk. It seemed to read it OK. I verified that it could correctly read a file that filled the entire disk. However... it totally crapped its pants and corrupted the file system when writing to it both in DOS and Windows!

The box also mentions 360RPM mode operation used by the Japanese 3.5" 1.25mb format, but I didn't test that.

This is a link to the product on the Microcenter web site: http://www.microcenter.com/product/420667/144MB_USB_External_Floppy_Disk_Drive_-_Black

But the box they show on the site looks different from what was in the store. In the store it was just a brown cardboard box labeled "USB Portable Diskette Drive". The drive itself is only labeled "USB Floppy Drive" "Made in China E77FCD393L" with no branding. The device manager identifies it as a "Y-E Data USB Floppy". So there is no telling if there will be any consistency as to what is really in the product. Still, might grab another one.

Interestingly these cost less than the Bytecc USB drives that can't read 720k.

Didn't see any more normal 1.44mb drives. I may have grabbed the last one from here a few months ago, although their site lists them for other locations. They do have several all-in-one card readers with a floppy that use the normal FDD interface instead of USB. I't crazy how they don't have any USB multi-card reader floppies even though they have other USB devices in them.

Chuck(G)
October 20th, 2013, 11:58 AM
As far as I am aware, the 720K and NEC 1.25M capability has always been part of standard USB drives. Certainly, it's called out in the old Teac FD005U (http://www.msc-ge.com/download/itmain/datasheets/teac/FD-005U-397.pdf) datasheed, back when USB was new.

Note that since a drive is addressed in USB in the same manner as a SCSI device (i.e. relative block, rather than CHS), format control is done by the drive, not the host. So you get 512/18/2/80, 512/9/2/80, 512/15/2/80 and 1024/8/2/80 formats only--and the host has no way to tell the drive to do anything differently.

Does anyone know of the existence of a 2.88M consumer-level USB floppy?

markyb86
October 21st, 2013, 02:12 AM
Any chance these would read/write a 800k floppy on a power mac ?(considering 720k floppies format as 800k on macs)

The Teac blue&white usb drive that matches the G3 tower only handles 1.44mb floppies.

SomeGuy
October 21st, 2013, 07:37 AM
No, they won't do the Apple 800k disks. Supposedly there was a Macintosh specific model but even that only does 1.44mb/720k. Dug up a FAQ on these drives, and they even mention that: http://www.yedata.com/support/floppydrives_faq.html

The Mac 800k disks/drives use GCR magnetic encoding instead of MFM encoding and vary their spindle speed.

Unfortunately that is kind of a complicated thing to implement. But at least a USB drive, if someone chose to make one like that, would not have to worry about a motherboard FDC's lack of support for GCR or motor control.

And on another note, what *REALLY* ever happened with 2.88mb drives anyway? My vague recollection from back in the day is that the drives and media were insanely overpriced. Was a patent holder charging huge licensing fees or something?

Chuck(G)
October 21st, 2013, 07:59 AM
The disks were expensive, but then so were DSHDs when they first came out. I never found the DSEDs to be terribly reliable. I have a box of new/old Imation DSEDs and I pulled one at random recently and fomatted it on a Teac FD235J that I have installed on one system here. Couldn't get through the format process without errors.

k2x4b524[
October 21st, 2013, 02:44 PM
I've got 2 2.88mb floppy drives, one in my PS/2 55SLC and the other is a mitsubishi, and about 30 2.88 DSED to go with them, The drives work flawlessly, the disks aren't too shabby either, i formatted them all in the PS/2, they were all old IBM Ultimedia disks, no errors. I just don't like waiting for the disks to write or format. That takes forever....

USB 2.88mb? Haven't seen one, But i've seen a 2.4mb 5.25" floppy drive
http://www.ebay.com/itm/YE-DATA-YD-802-6115-2-4MB-5-25-Floppy-Disc-Drive-P-N-1619631-/261303856923?pt=US_Floppy_Zip_Jaz_Drives&hash=item3cd6ec6f1b

markyb86
October 21st, 2013, 03:30 PM
And then combine that 2.4mb 5.25" floppy with this (http://www.deviceside.com/fc5025.html) floppy to USB adapter :D

Chuck(G)
October 21st, 2013, 03:41 PM
I've only ever seen the 5.25" 2.4M drive on IBM Comms controllers. Did anyone else ever use it?

k2x4b524[
October 21st, 2013, 03:52 PM
I've seen one in person, but not in action. Would it even work in a standard PC with the proper drivparm or driver.sys settings? I would think it's the same perpendicular tech the 2.88 uses, i'm in the dark on this one

vwestlife
October 21st, 2013, 03:59 PM
IBM used 2.88 MB floppy drives on many of their later PS/2 models, as well as some of their laptops. However, I just discovered that although it never came equipped with it, the PS/1 supports 2.88 MB floppy drives as well!

My PS/1 model 2121 (one of the early models with the power supply in the monitor) came with a dead 1.44 MB floppy drive, so to try to diagnose it, I borrowed the 2.88 MB floppy drive from my PS/2 Model 56-486SLC2 and plugged it in.

To my surprise, not only did the pinout match up exactly (since both supply power through the drive cable), but the PS/1 instantly recognized it as a 2.88 MB drive and configured as such it in its Hardware Setup program. Now it can format, read, and write 2.88 MB disks perfectly!

In fact, when formatting a 1.44 MB disk, you have to use the /F:1.44 switch, otherwise it will format it as 2.88 MB... which usually does work, but just like trying to format a 360K disk as 1.2 MB, the data will usually fade away and become unreadable over time, due to the magnetic field of the higher-density format being too strong for what the disk media can handle.

Chuck(G)
October 21st, 2013, 04:24 PM
I've seen one in person, but not in action. Would it even work in a standard PC with the proper drivparm or driver.sys settings? I would think it's the same perpendicular tech the 2.88 uses, i'm in the dark on this one

I once looked for a datasheet on the drive, but never succeeded in finding one.

SMichelsen
January 12th, 2017, 07:16 PM
Thanks for the tip! I found one of these drives on ebay. It does indeed read and write to a 720k floppy, and can even format one using FORMAT A: /T:80 N:9 on a cmd line. HOWEVER I cannot get it to accept the /s parameter to create a bootable floppy. I am using a windows 7 laptop; I guess the /s bit doesn't work with that OS. I think I need to dig out my XP laptop? Or is there another way to create a bootable 720k floppy with this drive and Win7?

Agent Orange
January 12th, 2017, 08:20 PM
Thanks for the tip! I found one of these drives on ebay. It does indeed read and write to a 720k floppy, and can even format one using FORMAT A: /T:80 N:9 on a cmd line. HOWEVER I cannot get it to accept the /s parameter to create a bootable floppy. I am using a windows 7 laptop; I guess the /s bit doesn't work with that OS. I think I need to dig out my XP laptop? Or is there another way to create a bootable 720k floppy with this drive and Win7?

I'm thinking that you need a source for the /s switch and it's not available in W7 - read/write only.

Chuck(G)
January 12th, 2017, 08:24 PM
It's a bit of a chicken-and-egg situation on Win 7 and later. Win 7 format isn't going to write the correct boot sector startup code, so even if you copied the necessary DOS files over, it still wouldn't boot.

The most straightforward way is to get a 720K DOS disk image from someone that can be written to the disk with something like WinImage. There are other ways, but you've got to get the image somehow.

konc
January 12th, 2017, 11:29 PM
The biggest problem I'm seeing with those USB floppy drives is not reading/writing DD disks, there are a lot of them that do it. But we're forced to have a tweener machine of some kind to write non-standard images, lacking a proper floppy controller these drives are only able to write specific PC formats.

SomeGuy
January 13th, 2017, 04:06 AM
I would not expect the /s parameter to do anything on an NT-based OS, as those do not have DOS.

You want to control what version of DOS you are writing anyway, so find a 1.44mb or 720k disk image set with the desired version of DOS in it and use WinImage or similar to write them.

Even real PC floppy controllers have their limits, especially when copy protection is present or non FM/MFM disks such as those from Apple II or Macintosh. I'll go ahead and mention that for those cases one may want a Kryoflux: http://www.kryoflux.com/ and/or SuperCard Pro: http://www.cbmstuff.com/proddetail.php?prod=SCP

Also, I noticed Microcenter changed around their current selection of USB drives. Off hand I don't know if any of those are 720k capable.

Chuck(G)
January 13th, 2017, 05:01 AM
My experience with the surplus USB floppies is that a common enclosure is used, but the drives inside can vary all over the place. Some time ago, I ordered three--all looked the same black nondescript enclosure, but one had a Sony, the second, a NEC and the third a Teac drive.

SMichelsen
January 13th, 2017, 10:07 AM
OK thanks for all that. I see now I need to use winimage, rather than just dump files onto a 720k floppy and expect it to work.

I have the downloaded file "IBM_PC_Convertible_Startup_103_image.dsk". Exactly where I got it I cannot recall; I suspect there's only a few places it could have come from...

Can someone please walk this image-using newbie how to turn this file, using winimage, into a working 720k boot disk?

Thanks!
Steve

PS: the file came with this handy scan:
https://dl.dropboxusercontent.com/u/65762317/forums/IBM_PC_Convertible_Startup_103_label.jpg

krebizfan
January 13th, 2017, 10:17 AM
Usually, all one has to do to create a disk with winimage is:

1) In the File menu, choose the Open item and in the dialog box select the disk image desired.

2) In the Diskette menu, choose the Write disk option. Insert diskette, make sure the correct drive is selected, and press the button.

99% of the time, it is just that easy.

lutiana
January 13th, 2017, 10:23 AM
I was not aware that there were issues with 720k disks under Windows XP/7 when using a USB floppy drive. The only thing that my Sony drive will not do it format 720kb disk, but other that that it'll read from them (files or create images) and write to them (files or images) . The format issue is not really a problem, since I can just do that on a DOS machine. This is under Windows 7 and Windows XP.

Stone
January 13th, 2017, 10:34 AM
I think the issues are more related to the drives' manufacturers than anything else in particular.

vwestlife
January 13th, 2017, 01:05 PM
I was not aware that there were issues with 720k disks under Windows XP/7 when using a USB floppy drive. The only thing that my Sony drive will not do it format 720kb disk, but other that that it'll read from them (files or create images) and write to them (files or images) . The format issue is not really a problem, since I can just do that on a DOS machine. This is under Windows 7 and Windows XP.

Windows XP and higher lacks the /F:720 option to force a 720 kB format, but you can do it manually by specifying the appropriate number of tracks and sectors, such as FORMAT A: /T:80 /N:9

lutiana
January 13th, 2017, 01:08 PM
Windows XP and higher lacks the /F:720 option to force a 720 kB format, but you can do it manually by specifying the appropriate number of tracks and sectors, such as FORMAT A: /T:80 /N:9

That is good to know. I will give it a go on that drive this weekend.