Re: Did Commodore cheat with the quad density floppies?

On 1/3/19 3:15 PM, Francesco Messineo wrote:

> I remember nobody ever tried to find "QD" disks, normal DD 48TPI disks
> were used (albeit I remember good quality brands were purchased
> usually, like 3M, Olivetti).

When I bought a whole lot of C64, 1541, an Amiga 2000A and some other 
stuff in 2011 for 20 Euros total on ebay (those were the days...), the 
lot also included about 500 floppy disks. When making D64 images from 
them, I came about a few QD disks, so they did exist.


> There're two different issues on compact cassette:
> 1) different (really much different) magnetic media, type I (Fe2O3,
> iron oxide), Type II (CrO2), type III (FeCr), type IV (metal), these
> media required different equalization and different recording
> currents. Type I are usually very bad sounding and noisy, type IV have
> the best quality, but the recorder really NEEDS to know what type of
> tape it's trying to record into, otherwise you wouldn't get much
> better results, unless maybe a bit less noise if you use a type IV
> tape on a old, low quality recorder.

Back when Type II was established, the type II tapes had an extra notch 
next to the erase control tab and most recorders had a sensor that 
detected the type that way. Wasn't something like this also added for 
type IV as well?

  Gerrit