Welcome, Guest. Please login or register.
Forums
« previous next »
Pages: [1]   Go Down

Author Topic: HD floppy in DD floppy drive - question  (Read 2154 times)

Description:

0 Members and 1 Guest are viewing this topic.

Offline mikeymikeTopic starter

  • Hero Member
  • *****
  • Join Date: Nov 2002
  • Posts: 3413
  • Country: 00
    • Show only replies by mikeymike
HD floppy in DD floppy drive - question
« on: November 01, 2011, 02:19:11 PM »
This question just occurred to me, and I'm just asking to challenge my opinion on this topic - it's been a long time since I did much with floppy disks, but I always had the feeling that HD floppy disks didn't seem to last very long when used in Amiga (DD) floppy drives.  Is this a complete load of rubbish?

Of course I understand that the full capacity of a HD floppy disk can't be used in a DD drive, my question is just about reliability/longevity.
Logged
 

Offline Zac67

  • Hero Member
  • *****
  • Join Date: Nov 2004
  • Posts: 2890
    • Show only replies by Zac67
Re: HD floppy in DD floppy drive - question
« Reply #1 on: November 01, 2011, 03:21:37 PM »
Actually not.
While the same coating was used for the longest period of DD floppy production, there's a problem with the way of writing. Once a disk has been written to just a single time with a HD drive (e.g. factory formatting)  the 'harder' magnetic imprint cannot be completely wiped out by a 'softer' DD head. (This is valid for DD disks used in HD drives, too!) Over time, the HD bits can creep back, wiping out the newer but softer DD bits.

So, for longevity - as most Amiga disks tend to be used - it's not advisable to use HD disks. One way to get around this is to use a HD drive even for DD media - but don't mix them with multiple drives. Probably the best way to store important data is on harddisk and backup to quality CD/DVD.
Logged
 

Offline LoadWB

  • Hero Member
  • *****
  • Join Date: Jul 2006
  • Posts: 2901
  • Country: 00
    • Show only replies by LoadWB
Re: HD floppy in DD floppy drive - question
« Reply #2 on: November 01, 2011, 03:55:03 PM »
Also look up "coercivity."  There are a metric shyte tonne of discussions around dar Interwebs about this topic as they crop up from time-to-time in various "retro" forums like ours.  Interesting stuff out there once you start digging.
Logged
 

Offline runequester

  • It\'s Amiga time!
  • Hero Member
  • *****
  • Join Date: Oct 2009
  • Posts: 3695
    • Show only replies by runequester
Re: HD floppy in DD floppy drive - question
« Reply #3 on: November 01, 2011, 04:18:59 PM »
In theory, yes, they may not last as long.

In practice, I've never had any issues with it, both back in the day, when I used floppies for everything, and nowadays, when I just use them for games.

I guess I'd be hesitant keeping very vital data, but even if you do use your amiga for anything important, odds are you have a hard drive and can take multiple backups anyway.
Logged
 

Offline LaserBack

  • Sr. Member
  • ****
  • Join Date: Mar 2007
  • Posts: 338
    • Show only replies by LaserBack
Re: HD floppy in DD floppy drive - question
« Reply #4 on: November 01, 2011, 05:25:18 PM »
Quote from: mikeymike;666065
HD floppy disks didn't seem to last very long when used in Amiga (DD) floppy drives.  Is this a complete load of rubbish?

.


it's a complete load of rubbish
hd floppies can last as long as dd floppies
in fact there are not technical differences between them ..only a hole
to store the floppies of course a sealed box away from moisture
otherwise they can get fungus like cd and dvds
Logged
 

Offline bbond007

  • Hero Member
  • *****
  • Join Date: Mar 2009
  • Posts: 1517
    • Show only replies by bbond007
Re: HD floppy in DD floppy drive - question
« Reply #5 on: November 01, 2011, 05:46:18 PM »
Quote from: mikeymike;666065
This question just occurred to me, and I'm just asking to challenge my opinion on this topic - it's been a long time since I did much with floppy disks, but I always had the feeling that HD floppy disks didn't seem to last very long when used in Amiga (DD) floppy drives.  Is this a complete load of rubbish?

Of course I understand that the full capacity of a HD floppy disk can't be used in a DD drive, my question is just about reliability/longevity.


I always found pre-formatted 1.44MB disks would frequently failed to format right away on track 0. What I would do is DMS a disk image to it. After that it would reformat just fine. I have no idea about the longevity.
Logged
 

Offline psxphill

Re: HD floppy in DD floppy drive - question
« Reply #6 on: November 01, 2011, 05:51:43 PM »
Quote from: LaserBack;666099
it's a complete load of rubbish
hd floppies can last as long as dd floppies
in fact there are not technical differences between them ..only a hole
to store the floppies of course a sealed box away from moisture
otherwise they can get fungus like cd and dvds

They are very different technically. Lots of stuff here:
 
http://www.retrotechnology.com/herbs_stuff/guzis.html
Logged
 

Offline LoadWB

  • Hero Member
  • *****
  • Join Date: Jul 2006
  • Posts: 2901
  • Country: 00
    • Show only replies by LoadWB
Re: HD floppy in DD floppy drive - question
« Reply #7 on: November 01, 2011, 06:43:54 PM »
Quote from: LaserBack;666099
it's a complete load of rubbish
hd floppies can last as long as dd floppies
in fact there are not technical differences between them ..only a hole
to store the floppies of course a sealed box away from moisture
otherwise they can get fungus like cd and dvds


Longevity-wise, no, there's little to no difference, except that today the quality as a whole is quite a bit less in the manufacture due to their reduced popularity and sales.  For instance, old micro-disks had a dust jacket through the entire internal surface, whereas now there's just a single patch -- arguably this is less effective than the full jacket.

However, there are technical differences between the two.
Logged
 

Offline Methuselas

  • Hero Member
  • *****
  • Join Date: Feb 2002
  • Posts: 2205
    • Show only replies by Methuselas
Re: HD floppy in DD floppy drive - question
« Reply #8 on: November 01, 2011, 06:48:41 PM »
Quote from: Zac67;666076
Actually not.
While the same coating was used for the longest period of DD floppy production, there's a problem with the way of writing. Once a disk has been written to just a single time with a HD drive (e.g. factory formatting)  the 'harder' magnetic imprint cannot be completely wiped out by a 'softer' DD head. (This is valid for DD disks used in HD drives, too!) Over time, the HD bits can creep back, wiping out the newer but softer DD bits.

So, for longevity - as most Amiga disks tend to be used - it's not advisable to use HD disks. One way to get around this is to use a HD drive even for DD media - but don't mix them with multiple drives. Probably the best way to store important data is on harddisk and backup to quality CD/DVD.



Ah, this explains why my disks corrupted so much back in the day!!! :furious:
Logged
\'Using no way as way. Having no limitation as limitation.\' - Bruce Lee

\'No, sorry. I don\'t get my tits out. They\'re not actually real, you know? Just two halves of a grapefruit...\' - Miki Berenyi

\'Evil will always triumph because good is dumb.\' - Dark Helmet :roflmao:

\'And for future reference, it might be polite to ask someone if you can  quote them in your signature, rather than just citing them to make a  sales pitch.\' - Karlos. :rtf
 

Offline LaserBack

  • Sr. Member
  • ****
  • Join Date: Mar 2007
  • Posts: 338
    • Show only replies by LaserBack
Re: HD floppy in DD floppy drive - question
« Reply #9 on: November 01, 2011, 08:29:23 PM »
Quote from: LoadWB;666114
Longevity-wise, no, there's little to no difference, except that today the quality as a whole is quite a bit less in the manufacture due to their reduced popularity and sales.  For instance, old micro-disks had a dust jacket through the entire internal surface, whereas now there's just a single patch -- arguably this is less effective than the full jacket.

However, there are technical differences between the two.


yep I agree
 also today floppies quality is very lame...the plastic is bad and soft....and I imagine that the surface and oxide of the disk is bad quality as well

btw, in the link posted by psxphill says that there is a difference in the oxide coercivity ..660 vs 720 anyways this can be theory....in practice I never found differences...hd disks always worked fine in the amiga and last long......and nobody can affirm correctly which one last long
« Last Edit: November 01, 2011, 08:39:44 PM by LaserBack »
Logged
 

Offline LaserBack

  • Sr. Member
  • ****
  • Join Date: Mar 2007
  • Posts: 338
    • Show only replies by LaserBack
Re: HD floppy in DD floppy drive - question
« Reply #10 on: November 01, 2011, 08:37:32 PM »
Quote from: bbond007;666101
I always found pre-formatted 1.44MB disks would frequently failed to format right away on track 0. What I would do is DMS a disk image to it. After that it would reformat just fine. I have no idea about the longevity.



another way to format those pre-formatted 1.44mb disks is format first with no verify then reformat with verify
Logged
 

Offline Zac67

  • Hero Member
  • *****
  • Join Date: Nov 2004
  • Posts: 2890
    • Show only replies by Zac67
Re: HD floppy in DD floppy drive - question
« Reply #11 on: November 01, 2011, 09:17:27 PM »
Quote from: LaserBack;666139
another way to format those pre-formatted 1.44mb disks is format first with no verify then reformat with verify


What's the point? Writing those disks several times may seem to solve the problem for the moment but doesn't really change anything longevity wise.
Logged
 
Pages: [1]   Go Up
« previous next »