yes, you will be able to format the floppies just fine for PC usage
if they are standard amiga floppies then they will be 720kb DD disks on pc

keropi wrote on Yesterday, 18:17:

yes, you will be able to format the floppies just fine for PC usage
if they are standard amiga floppies then they will be 720kb DD disks on pc

OK thanks for that!

720kb is only half of the 1.4MB standard
DD is one sided right?
HD is bough sided?

If only half the capacity then probably not worth bothering with for my usage. but hear is a link to them anyway https://www.ebay.co.uk/itm/267763391716

PS, i remember a while ago someone hear telling me that the smaller type disks only had one whole at the top (cant remember if this is true or not though) they look like they only have the one

Yes I have a big stack of blue DD ex-Amiga disks that I use with my XT that only has a DD controller.

The_Retro_Jimmy_Club wrote on Yesterday, 18:53:

OK thanks for that! […]
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keropi wrote on Yesterday, 18:17:

yes, you will be able to format the floppies just fine for PC usage
if they are standard amiga floppies then they will be 720kb DD disks on pc

OK thanks for that!

720kb is only half of the 1.4MB standard
DD is one sided right?
HD is bough sided?

If only half the capacity then probably not worth bothering with for my usage. but hear is a link to them anyway https://www.ebay.co.uk/itm/267763391716

PS, i remember a while ago someone hear telling me that the smaller type disks only had one whole at the top (cant remember if this is true or not though) they look like they only have the one

there are very few 1.44mb floppies on that listing from what I can see...
as is expected for an amiga the disks are DS/DD 720kb ones ... you can easily spot them because they only have 1 square hole (HD 1.44mb floppies have 2 holes)

The_Retro_Jimmy_Club wrote on Yesterday, 18:53:

720kb is only half of the 1.4MB standard
DD is one sided right?
HD is bough sided?

Both are double-sided.

3.5" Double Density = 9 sectors/track
3.5" High Density = 18 sectors/track

DD disks are precious for those with DD-only machines, eg. PC XT or Amiga.
PC AT (286 and above) support both DD and HD, so it's better to use HD.

The_Retro_Jimmy_Club wrote on Yesterday, 18:53:

720kb is only half of the 1.4MB standard
DD is one sided right?
HD is bough sided?

DD is Double Density
HD is High Density

Original floppy formats were Single Density = one clock bit per one data bit (almost nobody uses SD these days and many PCs FDCs can't do SD)
Double Density encoded differently requiring 1/2 the bits.
High Density is different still and is at a higher transition rate (500kbbs .vs. 300kbps on 3.5")

5.25" was not quite the same - a 5.25" drive rotates faster at HD (making the bits spread out more) which is why HD 5.25" is only 1.2m .vs. 1.44m for 3.5

Almost nobody uses single-sided drives any more

PC DS/DD 5.25" drive is 360k = 40tracks x 2heads x 9sectors x 512 bytes= 368,640 bytes

My Altair had Shugart SA400s (one of the first 5.25" drives) SS/SD 90k = 35tracks x 1 head x 10 sectors x 256 byes = 89,600

Quite a differnce in capacity - For information on common floppy drive characteristics - I refer you to the ImageDisk documents/help screens.

I have a box of Parrot single-sided 5.25" disks that I bought out of curiosity. They format to 180K as you would expect.

Errius wrote on Yesterday, 21:55:

I have a box of Parrot single-sided 5.25" disks that I bought out of curiosity. They format to 180K as you would expect.

Have you tried formatting them to 360 KB ?
I suspect they would format just as well - most (or even all?) "SS" floppies actually have the magnetic coating on both sides.

Yes, most SS disketts have media on both sides. The main difference is that during random testing, only one side is tested.

The_Retro_Jimmy_Club wrote on Yesterday, 18:53:

PS, i remember a while ago someone hear telling me that the smaller type disks only had one whole at the top (cant remember if this is true or not though) they look like they only have the one

Yes this is true for 3.5" disks. I've even had luck formatting a HD floppy as a DD one by covering the disk capacity hole.

TheMLGladiator wrote on Today, 01:05:

The_Retro_Jimmy_Club wrote on Yesterday, 18:53:

PS, i remember a while ago someone hear telling me that the smaller type disks only had one whole at the top (cant remember if this is true or not though) they look like they only have the one

Yes this is true for 3.5" disks. I've even had luck formatting a HD floppy as a DD one by covering the disk capacity hole.

Yes, the extra hole (opposite side from the Write protect slider) indicate to the drive/system that this is a high-density disk.

While it is possible to make a hole in the right spot to "fool" the drive into thinking a low-density diskette is high-density, and it *may* format, do keep in mind that the magnetic properties of LD and HD media are different, and using LD media at HD is not going to be reliable (it may appear reliable in your drive, but may not be in other drives, or as it ages).

Slightly related, some commercial pre-recorded disks are missing the slider to cover the write protect hole which effectively renders them permanently write-protected.

You can cover the hole with "black" tape to make it writable, or what I often do is: I made up a thin strip of opaque plastic which I can slie in on that side of the disk to cover the hole and make it temporarily writable!

Yeah you'd think covering those holes would be simple, but there's mechanical sensors and optical sensors. The optical sensors shine right through clear tape, the if you use some electrical tapes, they have enough elasticity in them for the mechanical actuator to dig in and think the hole is still there.

Sometimes you will get a PC saying the disk is bad, not sure if that's some Amiga bootblock stuff it doesn't like or whether it's the later vs original formats. Anyway, I ended up either formatting with CrossDOS on an Amiga to 720k or booting a live linux on a PC and formatting them from that. It's plainly a DOS/Windows problem, not sure if there's an alternate formatter that gets around it.

DaveDDS wrote on Today, 00:25:

Yes, most SS disketts have media on both sides. The main difference is that during random testing, only one side is tested.

Is this the same with the 3.5" floppies I listed above? I mean bough sides are magnetic? and if i cut another square hole out at the top then bough sides could be used giving me the 1.44mb?

DaveDDS wrote on Today, 01:38:

While it is possible to make a hole in the right spot to "fool" the drive into thinking a low-density diskette is high-density, and it *may* format, do keep in mind that the magnetic properties of LD and HD media are different, and using LD media at HD is not going to be reliable (it may appear reliable in your drive, but may not be in other drives, or as it ages).

You may of just answered my last question in my last post (if it get approved or not)

My current working Floppy drive (ignore my other post on broken floppy drive) is a Sony N50, modal MPF920-E, 26721654. Made in china 4-651-177-01. E / 131 APR2003 if that means anything! do you think it will work?

DaveDDS wrote on Today, 01:42:

Slightly related, some commercial pre-recorded disks are missing the slider to cover the write protect hole which effectively renders them permanently write-protected.

You can cover the hole with "black" tape to make it writable, or what I often do is: I made up a thin strip of opaque plastic which I can slie in on that side of the disk to cover the hole and make it temporarily writable!

This is what we used to do with the video cassettes back in the 90s that where supposed to be recorded on and sold as you say "pre-recorded cassettes" but instead where sold on the black market as blank cassettes