>Ethan Dicks wrote:
> > "Jerome H. Fine" <jhfinepw4z_at_compsys.to> wrote:
> > And why bother. Is a Teac FD55GFR a 5 1/4" HD 1.2 MByte floppy?
> Yes.
> > If so, it can probably be used as an RX33 with an RQDX3 on a real
> > DEC PDP-11.
> It is, AFAIK, _the_ model DEC used as the RX33, with the jumpers moved
> around from PeeCee use.
Jerome Fine replies:
I thought the model number sounded familiar. I received a few
5 1/4" HD 1.2 MByte floppy drives recently, but have had no time
to check them out. I think that at least one is the FD55GFR.
I also have two of the RX33 (actually labeled as such by DEC)
inside the shell of an RX50 (vacated since the RX50 was bad).
A Y power connector and a 34 pin cable with two edge connectors
at one end allows BOTH to be easily connected to an RQDX3.
Initially at first glance, it looks like an RX50, but closer examination
shows the handles for HD drives rather than the shutters for an RX50.
> > I would definitely NOT use an RX50 on a PeeCee!!!!!!!!!!!!!
> So I've heard from multiple people, but I'm still looking for a
> factual reason, not an emotional one. One reason to do it, at
> least from an "interesting hardware" standpoint, would be for quicker
> duplication of RX50s - put the source in one, the dest in another
> and go. The problem, of course, is that the PeeCee controller and/or
> software (E-11, RX50DRVR, etc.), might not expect such a strange beast
> and not do the right thing.
That is the obvious reason. But for myself, I am NOT very interested
in hardware as such. So anything that works is the best and only solution.
I have enough software bugs and enhancements to keep me busy for
a couple of decades.
> Obviously, putting two FD55GFRs in the same PeeCee could accomplish
> much the same thing. I'll have to go back and find my configuration
> instructions - I think the two drives I have were strapped for RX33
> use. They are *not* working in my PeeCee, but I _did_ find a 3.5"/5.25"
> combo drive that worked.
Since I use BINCOM 99.9% of the time to make sure that every image
that I copy from an RX50 (or any blocks at all for that matter) has been
copied correctly, there is not much reason to have two drives. It takes
just about the same time to copy an RX50 image to a temporary location
and then back to a second media as it takes to do the copy using two
floppy drives. When I include the BINCOM as well, the time is almost
doubled (almost since my version of BINCOM is usually able to do a
compare faster than the COPY - I use very large 96 block buffers and I
also double buffer - reading into the next buffers while I compare the
current buffers). It takes 152 KBytes of extended memory under the
RT11XM monitor, but the result is work while. The only time it is a
problem is when I must keep the buffers in the 18 bit address area
for an 18 bit device and that memory is already being used. I fixed
the DYX.SYS device driver to use a bounce buffer, but others have
not yet been fixed.
Sincerely yours,
Jerome Fine
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Received on Sat Jun 22 2002 - 09:11:17 BST