On 22 Jan 2007 at 5:22, Jules Richardson wrote:
Unfortunately a PC parallel port doesn't
quite have enough I/O lines, I
wouldn't have a clue how to make a USB solution (ick!), and building an ISA
card (say) would require kernel drivers (and all the complexity involved
there). One possibility is just to use two parallel ports, but that severely
limits the portability of the device - although I'm getting to the point where
that's preferable to not having any solution at all.
...or you can use one of the commodity data acquisition boards for a
PC. Plenty of I/O lines and simple enough to program from MS-
DOS/Windows 9x (lmits you to a file size of 4GB, but that should be
enough for older drives). I've got a PCI model here that uses 3 8255
PPI's (please, I know they're far from perfect) that cost about $60.
The ISA version of the card is even cheaper.
Hmm. DOS does have the advantage of not getting in the way of doing such
things (and I've already got a DOS PC for Imagedisk work). Plus it's nice to
have short startup times (and even faster shutdown ;)
The only downsides:
1) Lack of long filename support (if I'm archiving something I prefer to
give it a long name rather than having to poke into the archive contents to
see what something is),
2) Lack of remote administration (control via serial port or network would
be handy in some cases).
Longer term I could get around problem #1 if I built some sort of network
support into the application (FTP is perhaps the easiest) - I've been thinking
about doing this with Imagedisk anyway. So far I've not stumbled across any
good programming information for the various DOS TCP/IP stacks, though.
Problem #2 isn't a showstopper - it's just nice to be able to tuck the box out
of the way and control it via another system rather than it needing its own
keyboard / display taking up space.
So yes... DOS may well be the way forward (something probably not heard often :-)
cheers
Jules