Re: Did Commodore cheat with the quad density floppies?

Den Mon, 14 Jan 2019 09:21:56 +0100 skrev silverdr@wfmh.org.pl:
> 
> 
> > On 2019-01-13, at 12:10, Gerrit Heitsch <gerrit@laosinh.s.bawue.de>
> > wrote:
> > 
> >>> The thing about Video2000 was that it had better image quality.
> >>> No dropouts and no distortions when fast forwarding.
> >> 
> >> Bandwidth was similar if not the same (don't recall exactly now)
> >> but using half the tape width, dropouts are always there (medium
> >> dependent) but it didn't need any (manual) "tracking" (similar to
> >> head azimuth in C2N :-) due to advanced "DTF" solution. Therefore
> >> the inaccuracies were dynamically compensated, giving therefore
> >> better overall output. It also allowed distortion-free stills,
> >> slow-motion, fast-motion (both ways), fast winding both ways
> >> (_much_ faster than others), immediate recognition of the position
> >> of the tape with great accuracy - you could insert any tape in any
> >> position (no need to rewind), enter desired time from start, press
> >> "go to" and you landed where you wanted.
> > 
> > They managed to do this with VHS too, but much later.
> 
> I /think/ the first to do this was Grundig, once they dropped the
> towel and started to build VHS stuff. They surely had enough know-how
> from the V2000 development that could be put into use there. But the
> average time needed to reach arbitrary location was still much longer
> than with V2000.

The first Grundig VHS with that feature, the VS 200 (iirc), needed
barcode stickers on the tape or manually entering tape length, for this
to work. Later models didn't need this.

(They also produced a simpler VHS, VS 180, which didn't have any of
their fancy features).

Btw at the time they had some complicated options for the customer for
remote control. A VS 200 were supplied without any remote control and
without any remote control receiver, but it had a strange multi pin
DIN-ish socket on the rear. You could buy an IR reciever which were
fitted underneath and on the rear of the recorder. You could also buy
an interface/cable which connected to a 4-pin DIN socket on a Grundig
TV set. The remote control itself were also sold separately. The
rationale behind this mess was that if you had the appropriate TV you'd
only buy the interface/cable and use the IR receiver in the TV and the
VCR button on the remote of the TV. If you had a Grundig TV but without
the 4-pin socket, you could buy the IR receiver but still use the
remote of the TV. If you didn't have any of that, you'd buy both the
IR receiver and the remote. Or you just placed the recorder nearby your
favorite chair/sofa.

Btw Grundig did use the same kind of mechanism in their VHS recorders
as they had used in Video 2000 and VCR/SVR, i.e. one single arm
grabbing the tape and winding it a long way around the head, instead of
the two arms that most other VHS recorders used.

Their early VHS recorders had some strange behaviors which other VHS
brands had gotten rid of many years earlier, for example you had to
press some key to be able to display what the tuner did receive
(similar to pressing rec without play on the first VHS recorders ever
or on a cassette recorder), and it did turn off the picture after a
short while.

Philips early VHS recorders on the other hand had some other strange
behaviors, like for example you could operate parts of the mechanism
without any tape inserted.

> > And for the distortion free stills and forward/back, you needed 4
> > heads on VHS.
> 
> The only _fully_ distortion-free stills I saw on VHS, was with
> machines having framebuffer built-in (had some of those for studio
> work). The others tried to move the distortions to the bottom/vblank
> portion of the frame, out of the normally visible area. And for fast
> forward/back I don't recall any that would be completely
> distortion-free, in the sense V2000 was. AFAIR with advanced 4 heads
> machines the distortions were an order of magnitude less pronounced
> but still visible.

And you also needed extra heads for HIFI sound, and extra heads for
long play v.s. standard play, so you'd end up with a myriad of heads on
the drum.

While we anyway are rather off-topic: The first VHS recorder from
Hitachi, the VT-88 (aka B&O VHS 90 which were a slightly crippled VT-88
in a more fancy case) were based on one of their earliest VHS recorders
with long play, and it seems to have shared many parts. A funny thing
about many VHS recorders from japan were that the tape control buttons
on the front panels were connected with a resistor stage to one single
input pin on the control IC, and they all shared the same resistor
values and they used the same setup for their wired remote controls.
Back in the days I had a B&O VHS 90 which lacked it's remote control. I
just soldered in a 3.5mm mono tele jack in parallell with the pause
button in the recorder, and used an older wired remote control. That
did work fine and interestingly I also got a slow motion function which
weren't existing using the normal controls on that recorder (!). (Well,
in theory, in the audio only hifi mode it got a 2* speed mode, but that
was rather unusable as it didn't produce any sound :) ).


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