Do you double side your floppies?

ral-clan · Post by **ral-clan** » Tue Apr 11, 2006 1:08 pm

I remember back in the good ol' C64 days we always cut an extra notch out of our 5-1/4" disks so we could put games on both sides. I wonder why they never manufactured them like that (maybe they did).

Is this a safe practice, or does it make the discs less reliable in some way?

carlsson · Post by **carlsson** » Tue Apr 11, 2006 1:15 pm

A few brands came with dual write notches, marketed exclusively for Commodore and Atari owners, which were the only (?) home computer brands with single-sided disk drives that didn't check the index hole?

I have always used both sides of my DD disks, and never noticed any damage. It is however said that the dust filter on the inside of the jacket will release any particles which could scratch the surface when you flip the disk upside down and thus change the rotation direction. So, in a very bad case, you could damage the disk on one side if you use the other.

Likewise, it is not recommended to use both sides of a tape for data, in case signals leak over or something. I have plenty of double sided tapes, and never noticed this problem neither. But in theory..

Post by **Jeff-20** » Tue Apr 11, 2006 5:47 pm

Why would I? Disks are cheap and relatively fragile. I wouldn't risk double sided use.

6502dude · Post by **6502dude** » Tue Apr 11, 2006 7:25 pm

Jeff-20 wrote:Why would I? Disks are cheap and relatively fragile. I wouldn't risk double sided use.

Floppies were not always inexpensive.

I recall paying $20 for boxes of 10 SSDD generic floppy disks in early 80s.

Plus, back in those days $20 went a lot further than it does today.

Nowadays, I don't write stuff to real floppies unless it is something I am testing.

Bacon · Post by **Bacon** » Tue Apr 11, 2006 11:54 pm

Always did back then, always do now. Never had any problems. Even had one of those disk notchers in the '64 days, and I got one with one of the C64s I've bought the last few years, so I don't have to use scissors or an X-acto knife.

Mikam73 · Post by **Mikam73** » Wed Apr 12, 2006 5:16 am

Discs used to be very expensive at that time when 1541 did cost same as C64..

Wonder what customers would say today.. If disc drive would cost same as computer.. Yes.. I know that 1541 is like a computer, not just discdrive like those devices today.

I did always use both sides and no problems. Only problem was make that hole to disc, so you could use second side.

I remember all those storys that its not good use both sides.. and its bad if disc does not spin only one way.. Even that there could be problems course disc has that.. you know that ring thats center of disc.. only one side.

Well.. Those discs still work.. No problem..

carlsson · Post by **carlsson** » Wed Apr 12, 2006 6:53 am

Yeah, in the mid 80'ties, a single disk could cost 35 SEK, about $5 each. At the end of the decade, prices had dropped so Maxell cost 15 SEK ($2) each, and noname disks less than that. In the early 90'ties, 5.25" DD disks were obsolete and disappeared from the stores.

I also own a notcher, but in beginning used a pair of scissors. Mikam makes a good point about the enforced hub ring is only on one side, since double sided disks are designed for double sided drives. I have one or a few disks with double index holes even, but that is even more rare.

Some of my disks are SSDD, but it was even possible to use the back side of those. However, they are more error prone and it is not recommended. From what I understand, the 1541 drive operates with single density and GCR encoding to obtain a good capacity. I haven't seen any single density disk though, maybe they were obsoleted early in the 80'ties as disk drive manufacturers moved on to 48tpi DD.

ral-clan · Post by **ral-clan** » Wed Apr 12, 2006 8:01 am

I've always wondered how a magnetic head applied to one side of a floppy doesn't de-magnetize or wreck what is on the other side - considering a floppy disc surface is so thin. I guess the magnetic forces are not very strong.

As for good discs: I've found that my old BASF discs are some of the best for holding data. I recently found a 20 year old BASF disc with some of my old text files, graphics & programming from 1986. I was able to retrieve the files from BOTH sides with no corruption at all! I have experienced this reliability with other BASF discs as well.

I think BASF has gone down in quality since the mid 1990s. I know their VHS tapes are pretty low-quality now. But back in the 1980s they offered some of the best magnetic media you could buy (VHS, audio cassettes, floppy discs).

Boray · Post by **Boray** » Wed Apr 12, 2006 9:20 am

Yes, I use all of my diskettes on both sides. I have always done that and there has never been any trouble. So I really don't think there is any realistic reason not to do this. I remember one guy who thought it was too much work to clip all his diskettes, so he made a small modification to his diskdrive. He just bypassed the thing that checks for write protect. I think he maybe even had a switch on the diskdrive instead so he could turn the write protect on and off at any time...

I don't think any of my diskettes (most from 1988) has lost any data anywhere. In 1989 I bought noname disks for 2.65 SEK I think...

/Anders

Boray · Post by **Boray** » Wed Apr 12, 2006 9:24 am

I always used scissors and still do. It's not that hard if you use another diskette as a mould on top of it.

Post by **Jeff-20** » Wed Apr 12, 2006 6:07 pm

ral-clan wrote:I've always wondered how a magnetic head applied to one side of a floppy doesn't de-magnetize or wreck what is on the other side - considering a floppy disc surface is so thin.

Exactly! That's what I have always thought.

6502dude · Post by **6502dude** » Wed Apr 12, 2006 6:36 pm

Boray wrote:he made a small modification to his diskdrive. He just bypassed the thing that checks for write protect. I think he maybe even had a switch on the diskdrive instead so he could turn the write protect on and off at any time.../Anders

I did this switch mod and I had a switch to change address from 8 to 9.

Friends of mine back then had lots of switches, leds, etc on hardware

I never did have a disk notcher. For the first few, I used sissors. But results were not always consistent.

Mike · Post by **Mike** » Thu Apr 13, 2006 12:52 am

Jeff-20 wrote:
ral-clan wrote:I've always wondered how a magnetic head applied to one side of a floppy doesn't de-magnetize or wreck what is on the other side - considering a floppy disc surface is so thin.
Exactly! That's what I have always thought.

First of all: with some rare exceptions, discs were almost always produced double-sided. And then tested. When one of the sides didn't adhere to the (then high) standards, it was packaged as single sided.

The magnetic field doesn't 'wreck' the data of the bottom side, because like in the following schematic:

Code: Select all

  Head
V      A
V      A <- magnetic field
V      A
--------
 >>>>>>  <- top magnetic surface
--------

         <- plastic carrier

--------
         <- bottom magnetic surface
--------

the top magnetic surface acts like a short circuit to the magnetic field.

Greetings,

Michael

carlsson · Post by **carlsson** » Thu Apr 13, 2006 2:09 am

I have here two SKC disks of the same vintage. One is MD1S, one is double sided (MD1D? MD2S?). I have carefully touched the magnetic surface next to the hub ring (where no data is stored anyway), and it appears the single sided disk is slightly thinner than the double sided disk. It may be my imagination. The MD1S was formatted to two sides, being a bit more error prone on the back side - not supposed to be used.

Boray · Post by **Boray** » Thu Apr 13, 2006 6:31 am

Jeff-20 wrote:
ral-clan wrote:I've always wondered how a magnetic head applied to one side of a floppy doesn't de-magnetize or wreck what is on the other side - considering a floppy disc surface is so thin.
Exactly! That's what I have always thought.

Hmmm.... Do you store just 720kb on a 1.44MB diskette as well?