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floppy disk question

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  floppy disk question Mark Lemmert <mark.lemmert@gmail.com> - 2017-02-02 14:09 -0800
    Re: floppy disk question Michael J. Mahon <mjmahon@aol.com> - 2017-02-02 16:34 -0600
    Re: floppy disk question D Finnigan <dog_cow@macgui.com> - 2017-02-02 22:39 +0000
      Re: floppy disk question Michael J. Mahon <mjmahon@aol.com> - 2017-02-03 12:17 -0600
    Re: floppy disk question gids.rs@sasktel.net - 2017-02-02 17:22 -0800
      Re: floppy disk question qkumba <peter.ferrie@gmail.com> - 2017-02-03 10:17 -0800
        Re: floppy disk question Mark Lemmert <mark.lemmert@gmail.com> - 2017-02-03 13:24 -0800
    Re: floppy disk question roger.shimada@gmail.com - 2017-02-02 18:33 -0800
      Re: floppy disk question Jurai <Jurai@WhereTheHellAmI.???> - 2017-02-11 15:11 -0700
        Re: floppy disk question Leeland Heins <leelandheins@gmail.com> - 2017-03-08 15:38 -0800
      Re: floppy disk question Leeland Heins <leelandheins@gmail.com> - 2017-03-08 15:34 -0800
        Re: floppy disk question roger.shimada@gmail.com - 2017-03-08 19:44 -0800
    Re: floppy disk question Mark Lemmert <mark.lemmert@gmail.com> - 2017-02-03 13:25 -0800
    Re: floppy disk question laseractiveguy@gmail.com - 2017-02-11 18:03 -0800
      Re: floppy disk question 6502workshop@gmail.com - 2017-02-12 15:44 -0800
      Re: floppy disk question Mark Lemmert <mark.lemmert@gmail.com> - 2017-02-12 17:34 -0800

#3236 — floppy disk question

In the 1980s when using 5.25” floppy disks on the Apple II my recollection is that I always used DS/DD (double-sided double-density) disks. I also recall that whatever DS/DD disks I bought, I was always able to punch a 2nd notch on the left side of the disk and physically flip the disk over to access the side2 of the disk (i.e. a flippie disk if that is the correct term), for 360k capacity total, 180k per side. 


I’ve had some discussions recently with vendors who sell 5.25” DS/DD disks in bulk and I’ve had trouble getting a straight answer on whether they can be used as flippie disks. 

Based on my online research of floppy disk schematics it sure looks to me like any DS/DD disk should be able to be used as a flippie disk in an Apple II computer, but before I buy a large quantity, I was wondering if anybody can over a perspective on this?

Specifically, when buying 5.25” floppy disks is there any specs I need to look for other than DS/DD to ensure that I can use them as 360k flippie disks with 180k per side?



Thanks much for any advice anybody has to offer!


Mark

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#3237

Mark Lemmert <mark.lemmert@gmail.com> wrote:
> In the 1980s when using 5.25” floppy disks on the Apple II my
> recollection is that I always used DS/DD (double-sided double-density)
> disks. I also recall that whatever DS/DD disks I bought, I was always
> able to punch a 2nd notch on the left side of the disk and physically
> flip the disk over to access the side2 of the disk (i.e. a flippie disk
> if that is the correct term), for 360k capacity total, 180k per side. 
> 
> 
> I’ve had some discussions recently with vendors who sell 5.25” DS/DD
> disks in bulk and I’ve had trouble getting a straight answer on whether
> they can be used as flippie disks. 
> 
> Based on my online research of floppy disk schematics it sure looks to me
> like any DS/DD disk should be able to be used as a flippie disk in an
> Apple II computer, but before I buy a large quantity, I was wondering if
> anybody can over a perspective on this?
> 
> Specifically, when buying 5.25” floppy disks is there any specs I need to
> look for other than DS/DD to ensure that I can use them as 360k flippie
> disks with 180k per side?
> 
> 
> 
> Thanks much for any advice anybody has to offer!
> 
> 
> Mark
> 

Yes, they'll all work when you flip them. 

One note:  Apple 5.25" disks are 140K, not 180, and their recording density
is actually single density, but more common DD disks work identically
because they have the same magnetic media, just higher density
certification. 

-- 
-michael - NadaNet 3.1 and AppleCrate II:  http://michaeljmahon.com

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#3239

Mark Lemmert wrote:
> 
> Based on my online research of floppy disk schematics it sure looks to me
> like any DS/DD disk should be able to be used as a flippie disk in an
> Apple
> II computer, but before I buy a large quantity, I was wondering if anybody
> can over a perspective on this?
> 

This is a topic that can be made as simple or as complicated as we want to
make it. I'll skip technical features of the Disk II drive relative to
single-sided vs double-sided, and will leave that to others, but I'll say
this:

I've read the "historical" discussions on flippy disks on Usenet from the
80s and 90s and the one interesting point that was brought up a few times is
that when you physically flip a disk, suddenly the magnetic media is
rotating in the opposite direction. If there's dust buildup in the felt
padding/liner inside the plastic sleeve, suddenly the media is dragging
*against* the dust instead of *with* the dust.

The point here being that the effects of this reversal may be something that
wears out the recording surface faster, such as by digging a nice gouge in
the media.

My own personal experience is that the best way to put a nice gouge on the
disk surface is by using the disk in a drive that has a dirty head. I've got
a lot of disks now 30 years old, nearly all flippy, and haven't had problems
that I believe were related to flipping them.

-- 
]DF$
The Marina IP stack for Apple II--
http://marina.a2hq.com/

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#3243

D Finnigan <dog_cow@macgui.com> wrote:
> Mark Lemmert wrote:
>> 
>> Based on my online research of floppy disk schematics it sure looks to me
>> like any DS/DD disk should be able to be used as a flippie disk in an
>> Apple
>> II computer, but before I buy a large quantity, I was wondering if anybody
>> can over a perspective on this?
>> 
> 
> This is a topic that can be made as simple or as complicated as we want to
> make it. I'll skip technical features of the Disk II drive relative to
> single-sided vs double-sided, and will leave that to others, but I'll say
> this:
> 
> I've read the "historical" discussions on flippy disks on Usenet from the
> 80s and 90s and the one interesting point that was brought up a few times is
> that when you physically flip a disk, suddenly the magnetic media is
> rotating in the opposite direction. If there's dust buildup in the felt
> padding/liner inside the plastic sleeve, suddenly the media is dragging
> *against* the dust instead of *with* the dust.
> 
> The point here being that the effects of this reversal may be something that
> wears out the recording surface faster, such as by digging a nice gouge in
> the media.
> 
> My own personal experience is that the best way to put a nice gouge on the
> disk surface is by using the disk in a drive that has a dirty head. I've got
> a lot of disks now 30 years old, nearly all flippy, and haven't had problems
> that I believe were related to flipping them.
> 

Exactly. 

The "dangers" of flipping were theoretical, not borne out in practice. 

-- 
-michael - NadaNet 3.1 and AppleCrate II:  http://michaeljmahon.com

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#3240

On Thursday, February 2, 2017 at 4:09:38 PM UTC-6, Mark Lemmert wrote:
> In the 1980s when using 5.25” floppy disks on the Apple II my recollection is that I always used DS/DD (double-sided double-density) disks. I also recall that whatever DS/DD disks I bought, I was always able to punch a 2nd notch on the left side of the disk and physically flip the disk over to access the side2 of the disk (i.e. a flippie disk if that is the correct term), for 360k capacity total, 180k per side. 
> 
> 
> I’ve had some discussions recently with vendors who sell 5.25” DS/DD disks in bulk and I’ve had trouble getting a straight answer on whether they can be used as flippie disks. 
> 
> Based on my online research of floppy disk schematics it sure looks to me like any DS/DD disk should be able to be used as a flippie disk in an Apple II computer, but before I buy a large quantity, I was wondering if anybody can over a perspective on this?
> 
> Specifically, when buying 5.25” floppy disks is there any specs I need to look for other than DS/DD to ensure that I can use them as 360k flippie disks with 180k per side?
> 
> Thanks much for any advice anybody has to offer!
>
> Mark


Just out of curiosity, is this a nostalgia thing that you would want floppies as a recording media instead of using an emulator that, under Prodos can access 32 Mb drives, and even under Dos 3.3, there is very little switching or flipping disks?

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#3244

> Just out of curiosity, is this a nostalgia thing that you would want floppies as a recording media instead of using an emulator that, under Prodos can access 32 Mb drives, and even under Dos 3.3, there is very little switching or flipping disks?

The plan is to release the game on physical floppies, hence the need for physical floppies.

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#3246

On Friday, February 3, 2017 at 12:17:33 PM UTC-6, qkumba wrote:
> > Just out of curiosity, is this a nostalgia thing that you would want floppies as a recording media instead of using an emulator that, under Prodos can access 32 Mb drives, and even under Dos 3.3, there is very little switching or flipping disks?
> 
> The plan is to release the game on physical floppies, hence the need for physical floppies.

qkumba is correct. Floppies for those who want the nostalgia and thanks to his ProRWTS driver, the game will also be ProDOS compatible for hard drive use. 

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#3241

On Thursday, February 2, 2017 at 4:09:38 PM UTC-6, Mark Lemmert wrote:
> In the 1980s when using 5.25” floppy disks on the Apple II my recollection is that I always used DS/DD (double-sided double-density) disks.

Single sided single density disks weren't around that long. Both sides could be used on many of them.

> I also recall that whatever DS/DD disks I bought, I was always able to punch a 2nd notch on the left side of the disk and physically flip the disk over to access the side2 of the disk ...

The hole is required for the write protect sensor.

> for 360k capacity total, 180k per side. 

Oooh...sounds like you used some hack that used 40 tracks instead of 35.

That might be a problem for some disk emulators.

> I’ve had some discussions recently with vendors who sell 5.25” DS/DD disks in bulk and I’ve had trouble getting a straight answer on whether they can be used as flippie disks. 

The major concern would be "hard sectors", which need to read the small index hole near the main hole. IBM compatible formats are hard sectored. (So making a flippy for a single sided IBM drive meant creating additional holes for the index.) Apple and Commodore use soft sectors, so flippies could be used on both. (Not that Commodore drives should trusted much.)
 
> Specifically, when buying 5.25” floppy disks is there any specs I need to look for other than DS/DD ...

Nope.

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#3269

On Thu, 2 Feb 2017 18:33:39 -0800 (PST), roger.shimada@gmail.com
wrote:

>On Thursday, February 2, 2017 at 4:09:38 PM UTC-6, Mark Lemmert wrote:
>> In the 1980s when using 5.25” floppy disks on the Apple II my recollection is that I always used DS/DD (double-sided double-density) disks.
>
>Single sided single density disks weren't around that long. Both sides could be used on many of them.
>
>> I also recall that whatever DS/DD disks I bought, I was always able to punch a 2nd notch on the left side of the disk and physically flip the disk over to access the side2 of the disk ...
>
>The hole is required for the write protect sensor.
>
>> for 360k capacity total, 180k per side. 
>
>Oooh...sounds like you used some hack that used 40 tracks instead of 35.
>
>That might be a problem for some disk emulators.
>
>> I’ve had some discussions recently with vendors who sell 5.25” DS/DD disks in bulk and I’ve had trouble getting a straight answer on whether they can be used as flippie disks. 
>
>The major concern would be "hard sectors", which need to read the small index hole near the main hole. IBM compatible formats are hard sectored. (So making a flippy for a single sided IBM drive meant creating additional holes for the index.) Apple and Commodore use soft sectors, so flippies could be used on both. (Not that Commodore drives should trusted much.)
> 
>> Specifically, when buying 5.25” floppy disks is there any specs I need to look for other than DS/DD ...
>
>Nope.

The last time I remember running into a "hard sector"ed disk, I was
working with 8" floppy's.  Can't recall ever using a 5.25 one, though
at this age, it's getting harder & harder to recall anything!
                                                             -- Jurai

Hippies!  Get off my lawn!!!

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#3348

On Saturday, February 11, 2017 at 4:11:22 PM UTC-6, Jurai wrote:
> On Thu, 2 Feb 2017 18:33:39 -0800 (PST), roger....@....com
> wrote:
> 
> >On Thursday, February 2, 2017 at 4:09:38 PM UTC-6, Mark Lemmert wrote:
> >> In the 1980s when using 5.25” floppy disks on the Apple II my recollection is that I always used DS/DD (double-sided double-density) disks.
> >
> >Single sided single density disks weren't around that long. Both sides could be used on many of them.
> >
> >> I also recall that whatever DS/DD disks I bought, I was always able to punch a 2nd notch on the left side of the disk and physically flip the disk over to access the side2 of the disk ...
> >
> >The hole is required for the write protect sensor.
> >
> >> for 360k capacity total, 180k per side. 
> >
> >Oooh...sounds like you used some hack that used 40 tracks instead of 35.
> >
> >That might be a problem for some disk emulators.
> >
> >> I’ve had some discussions recently with vendors who sell 5.25” DS/DD disks in bulk and I’ve had trouble getting a straight answer on whether they can be used as flippie disks. 
> >
> >The major concern would be "hard sectors", which need to read the small index hole near the main hole. IBM compatible formats are hard sectored. (So making a flippy for a single sided IBM drive meant creating additional holes for the index.) Apple and Commodore use soft sectors, so flippies could be used on both. (Not that Commodore drives should trusted much.)
> > 
> >> Specifically, when buying 5.25” floppy disks is there any specs I need to look for other than DS/DD ...
> >
> >Nope.
> 
> The last time I remember running into a "hard sector"ed disk, I was
> working with 8" floppy's.  Can't recall ever using a 5.25 one, though
> at this age, it's getting harder & harder to recall anything!
>                                                              -- Jurai
> 
> Hippies!  Get off my lawn!!!

I ran into a CP/M machine, I can't remember what brand it was, back in the day that used hard sectored 5.25" floppies.  Instead of a single little hole that went past the index sensor like on most floppies they had one index sensor hole per sector.  FWIW, the Disk II didn't even use the sector index sensor and some drives didn't even have one since it was unnecessary due to the way self sync bytes worked in Woz's GCR scheme.  I think most if not all MFM drives like typically used on CP/M and MS-DOS based systems used the sensor.

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#3347

On Thursday, February 2, 2017 at 8:33:40 PM UTC-6, roger....@gmail.com wrote:
> On Thursday, February 2, 2017 at 4:09:38 PM UTC-6, Mark Lemmert wrote:
...
> > for 360k capacity total, 180k per side. 
> 
> Oooh...sounds like you used some hack that used 40 tracks instead of 35.
> 
> That might be a problem for some disk emulators.
...

Actually a 40 track Apple II disk is only 160k.  16 sectors of 256 bytes each = 4k per track x 5 tracks = 20k + the 140k standard.

Not only could 40 tracks cause an issue for emulators that assume 35 tracks, it can even cause an issue for a lot of earlier Disk II drives that have a stop in them so they won't go past track 35 (sometimes 36).  Later drives didn't all have that and neither did most 3rd party drives.  I had a bunch of Franklin surplus SA390 mechanisms and they all happily did 40 tracks as did most of the drives from companies like Rana Systems and Micro-Sci.

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#3351

On Wednesday, March 8, 2017 at 5:34:51 PM UTC-6, Leeland Heins wrote:
> On Thursday, February 2, 2017 at 8:33:40 PM UTC-6, roger....@gmail.com wrote:
> > On Thursday, February 2, 2017 at 4:09:38 PM UTC-6, Mark Lemmert wrote:
> ...
> > > for 360k capacity total, 180k per side. 
> > 
> > Oooh...sounds like you used some hack that used 40 tracks instead of 35.
> ...
> 
> Actually a 40 track Apple II disk is only 160k.  16 sectors of 256 bytes each = 4k per track x 5 tracks = 20k + the 140k standard.

Right. No more doing math in my head.

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#3247

Many thanks to everyone who replied. That clears up this question for me and as usual offered some additional interesting insights!


Mark

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#3270

Any hint as to what type of game its going to be... and Lores, Double-Lores or one of the high res modes?

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#3276

On Saturday, February 11, 2017 at 8:04:00 PM UTC-6, laserac...@gmail.com wrote:
> Any hint as to what type of game its going to be... and Lores, Double-Lores or one of the high res modes?


Sure, thanks for your interest. 


The game is called Nox Archaist, and it is a sword & sorcery themed tile-based RPG. 

The game engine is almost complete, and uses single hi-res for all tile graphics. There might be a DHGR splash screen and DHGR portraits for NPCs & mobs if there is enough floppy disk space. 


If you are interested in more of preview info, here are a few links:


Gameplay Video: 

Nox Archaist S1E1: Shattered Sword
https://youtu.be/0ecDcrH-MGw

In this episode our hero travels to town and faces an epic struggle to get his sword repaired after breaking it over an ogre's head.


Blog Post describing what game will be like:
http://www.6502workshop.com/search/label/Blog


Game Website:
http://www.noxarchaist.com



Mark

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#3277

On Saturday, February 11, 2017 at 8:04:00 PM UTC-6, laserac...@gmail.com wrote:
> Any hint as to what type of game its going to be... and Lores, Double-Lores or one of the high res modes?

Sure, thanks for your interest. 


The game is called Nox Archaist, and it is a sword & sorcery themed tile-based RPG. 

The game engine is almost complete, and uses single hi-res for all tile graphics. There might be a DHGR splash screen and DHGR portraits for NPCs & mobs if there is enough floppy disk space. 


If you are interested in more of preview info, here are a few links: 


Gameplay Video: 

Nox Archaist S1E1: Shattered Sword 
https://youtu.be/0ecDcrH-MGw 

In this episode our hero travels to town and faces an epic struggle to get his sword repaired after breaking it over an ogre's head. 


Blog Post describing what game will be like: 
http://www.6502workshop.com/search/label/Blog 


Game Website: 
http://www.noxarchaist.com 



Mark 

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