Path: utzoo!utgpu!watmath!iuvax!cica!tut.cis.ohio-state.edu!attctc!wnp
From: wnp@attctc.Dallas.TX.US (Wolf Paul)
Newsgroups: comp.sys.ibm.pc
Subject: Re: make your own HD 3 1/2 in floppies
Message-ID: <8696@attctc.Dallas.TX.US>
Date: 18 Jul 89 03:11:43 GMT
References: <26260@amdcad.AMD.COM> <8020020@hp-lsd.HP.COM> <8649@attctc.DALLAS.TX.US> <435@berlioz.nsc.com>
Reply-To: wnp@attctc.Dallas.TX.US (Wolf Paul)
Distribution: na
Organization: The Unix(R) Connection BBS, Dallas, Tx
Lines: 41

In article <435@berlioz.nsc.com> gwang@berlioz.UUCP (George Wang) writes:
+In article <8649@attctc.DALLAS.TX.US> wnp@attctc.Dallas.TX.US (W. Paul) writes:
+
+>of 360K, 1.2M, 720K and 1.44M diskettes, respectively. Apparently, the
+>surface difference between double and high density 3.5" diskettes is NOT
+>THE SAME as the difference between double and high density 5.25" disks.
+>
+Correction! There *IS* a difference in the magnetic media of
+3.5 High Density and Low Density diskettes... If you examine the
+medias of NAME BRAND diskettes you will notice a visible difference
+in the media of low and high density 3.5 diskettes... Furthermore,
+high density drives write in a lower signal level than low
+densities...
+
+are high density certified are using the same "hole punch" trick...
+But Name brand diskette companies such as 3M produce diskettes
+that do *NOT* have the same media surfaces... The same difference
+exists in 5.25 diskettes...
+

Notice that I didn't say that there is NO difference between DD and HD 3.5"
disks, but rather that it doesn't seem to be the same difference as between
DD and HD 5.25" disks.

If you dispute that, back it up with specific coercivity values, and tell me
why I can use my hole punch on a DD 3.5" disk, and then format it to
1.44MB with NO BAD SECTORS, while I am UNABLE to format a DD 5.25" disk
to 1.2MB. And I tried this on many different drives -- so don't tell me
its my 5.25" drive. It's the media allright.

And visual differences are pretty irrelevant -- they can be intentional,
to mislead the user into thinking there is a difference. Its like diesel fuel
in Europe -- non-taxed fuel for agricultural use is dyed differently from
taxed fuel for road use, and the same diesel fuel for heating purposes is
colored still differently. The only difference is the dye, and the price to
the enduser.
-- 
Wolf N. Paul * 3387 Sam Rayburn Run * Carrollton TX 75007 * (214) 306-9101
UUCP:   {texbell, attctc, dalsqnt}!dcs!wnp
DOMAIN: wnp@attctc.dallas.tx.us or wnp%dcs@texbell.swbt.com
        NOTICE: As of July 3, 1989, "killer" has become "attctc".