13 Dec
2006
13 Dec
'06
2:13 a.m.
Haven't been following this list for some time, but the few times I do look
at archived listings I find gems like these. Thanks for the link Chuck as
futurlec is the first place that I've found that carries a PCI digital I/O
card for only $40! (A lot easier option than my building one in my (almost
non-existent) spare time).
To put in my $0.02 worth about the machine independant storage idea, I'm
partial to using IDE disks as the medium as these are directly readable by
PC's via an external IDE firewire to PC interface and could also be used as
a disk drive on the old machine. I started the design of a parallel port
to IDE interface for the PDP-11 a few years ago but this was shelved when
my girlfriend told me that either the PDP-11/23 MINC system in my living
room went or she went. Still have the PDP-11 system, but she doesn't know
where I've stashed it.
Parallel port type interfaces are available on most old machines and if one
used a USB flash drive, one would have to do serial to parallel data
conversion as part of the interface, so why not go with a parallel data
interface the whole way? Flashdrives are smaller, but most of my PC's
don't have USB interfaces and I can quickly add an IDE disk drive to my old
systems for copying data. Another option is to use a serial port for
transfers and this is how I used to load software on my diskless PDP-11
systems. Can't get much simpler than that.
On 6 Dec 2006 at 10:46, Simon Fryer wrote:
I was thinking of doing the same sort of thing
but using compact flash
cards and building some electronics as the interface for the QIC tape
interface. Thinking about it is about as far as I got. From what I
understand, the electronics and software for interfacing Compact Flash
is a little easier than USB.
I've been toying with the idea of using a CF to provide emulation for
floppy drives. More complicated, as the thing has to look like a
floppy. Rather than record separated data, I'm inclined to record
flux transitions on the CF, so a disk would require something on the
order of 128KBytes per track (for a 300 RPM 500KHz drive). i.e.,
the drive would be data-encoding independent. Since one can get 4GB
CF cards, this shouldn't be a problem . Managing multiple images
from a single CF card will require some careful thought. Simulating
multiple drives with a single unit is another possibility.
There are still whole segments of the industrial market where
floppies represent the only available interface for older equipment.
For the interested, here's a RS232/485-to-CF card development board.
Note that it's pretty simple, using a PIC for most functions.
http://www.futurlec.com/CompBoard_Technical.shtml
I've been using the same outfit's USB-to-parallell I/O module and
find that it's easy to use (and plugs into a 32-pin DIP socket).
Cheers,
Chuck