[rescue] Sick Dreamcast hacker

Joshua D Boyd jdboyd at cs.millersville.edu
Tue Jun 18 09:47:23 CDT 2002


On Tue, Jun 18, 2002 at 10:31:30AM -0400, Dave McGuire wrote:
>   It means you can't share interrupts between peripherals.

Ahh.  Yes, that is a bummer.
 
> > Yes, it is painfully slow.  But it still can be used for worthwhile
> > things.  It is fast enough to stream flac files, or to play well
> > compressed video.  Let alone being fast enough to read and store
> > email, or whatever else.
> 
>   Yes, you make an excellent point as always.  It has been, however,
> badly abused and misapplied to tasks it was never designed to do, and
> isn't particularly good at...like LOTS of other PeeCee hardware.
 
> > I was fine with ISA (speed aside) until people started trying to make
> > it PnP.
> 
>   Agreed.  I can't tell you the number of time I've lost sleep over
> 3C509 cards.  Blargh.

I hated ISAPNP under linux so much that in 2000 I took my main
workstation and main server and replaced all remaining ISA cards with
PCI cards.  I don't know how windows manages to make it mostly work (I
hate to say it but for the most part is I toss a ISA PNP card into a
windows machine it just works without trouble).

I'm at a loss for what to do for sound cards though.  I'm increasingly
unhappy with the SBLive!s linux support, but it appears that my only
choises are to move back to ISA cards (I have a turtle beach card that
is very well supported except for that ISAPNP thing) or move up to a
RME DIGI card (rarely show up on ebay, usually expensive, requires a
seperate $100 driver, and requires seperate AD/DA units).

At the moment it isn't too much of an issue, but I want to sooner or
later set up an area for recording etc, and while Opcode on a Mac is
great for recording, there are an increasing number of cool linux
tools (effects that are almost fast enough for inline usage,
accompanyment software, virtual synths, etc).  But, maybe things will
change by the time I have the spare time to do something like this.

> > And the docs I have make it look easy enough to build cards for.
> 
>   That doesn't make it a well-designed bus. ;)

Well, true.
 
>   The ISA bus was never designed to be a generic end-all be-all bus.
> It's basically a physical extension of the 8088's bus with some
> interrupt and DMA stuff tacked on, and not much else.  For what it is,
> it's perfectly reasonable.  But compared to much more modern buses
> like Sbus and PCI it's rather primitive.

I wouldn't argue there.  But then again, I can't really imagine ever
making my own sbus or PCI card, so perhaps sometimes primitive is
good. 
 
>   But yes, it's very easy to build stuff for.  In that it still has
> tremendous value, in my opinion.

I suspect that is why it keeps showing up in devices like the DC and
the Tivo.  It obviously is fast enough for a 10mbit ethernet device,
and they want something simple and cheap.
 
>   So here I am trying to come up with a circuit to reduce the duty cycle
> of a 460KHz square wave down to about 12-15% using a small number of
> inexpensive components.  I like hacking electronics, but this part is
> *not* fun.

I'll assume that what you said is really hard since I don't know what
duty cycles for square waves are.  Do you mean reduce the frequency
12-15% or what?

-- 
Joshua D. Boyd



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