Date   : Tue, 16 Jul 1985 17:38:23 GMT
From   : "R.Thomas" <rbt%sftig.uucp@BRL.ARPA>
Subject: Re: using both side of disks

> 
> It is absolutely safe to use both sides of a disk on a 1541 disk-drive
> if the disks are certified double-sided on the box, and there is a
> write-protect notch cut on both side edges of the disk.  If not, then
> it is risky to use the uncertified side for data storage.
> 
> If you buy a commercial software product which uses both sides of a
> disk, then it is probably safe to assume that they are using the
> correct kind of disk.
> 
> 
> --- Andy Brown 

Interesting.  I have *never* seen a disk with notches cut on both sides,
except when I have personally known the person who cut them.  Most 'double
sided' software distribution disks I have seen have actually not had
notches on *either* side.  They must have been produced on duplicating
machines that ignored the presence or absence of write protect notches.

On the other hand, I have the following philosophy on 'flippy' disks --
Because of the dirt entrapment/releasing problem, it is never a good idea
to use the 'back' side of a disk, unless the disk is (almost) brand new.
That means that for day to day use, if you only have a single sided drive,
you should only use the front side of your disks.  Whether you buy disks
marked 'single sided' or 'double sided' is a matter of personal preference,
especially since the price difference is so small, nowadays.  I buy 'double
sided' disks, personally, because of the following observation --  There
*is* one safe use for 'flippy' disks.  That is for distributing software
that is too big to fit on a single side.  In that case, you are going to
use a new -- fresh out of the box -- disk, so you are not worried about
dirt, and the recipient is going to make a backup copy (onto *two* disks!)
as soon as she gets it, then put it away and (hopefully) never have to
read it again, so she is not worried about dirt either.  I do enough
software swapping that I find it useful to have a supply of 'double sided'
disks readily available at all times.

As an aside, I don't think it is possible to design a liner that will not
entrap some dirt, and release it if the disk is spun the other way.  That
just seems like the the inevitable workings of the laws of physics to me.

Enjoy!

Rick Thomas
ihnp4!attunix!rbt