29 Feb
2008
29 Feb
'08
7:03 a.m.
Subject: Re: Q-bus to CF [was: IOmega]
From: der Mouse <mouse at Rodents.Montreal.QC.CA>
Date: Fri, 29 Feb 2008 02:00:53 -0500 (EST)
To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
classiccmp.org>
the likely reason is PDP-11 and VAX does read before write and IDE
does not like that. The fis is to make the READ address different
Generally IDE and CF (compactflash) are the same
interface and for
Qbus-11 fairly simple. It's been done, however, the problem is the
driver as bare IDE or CF is NOT MSCP not is it DL, DX, DY or RK so a
driver is needed and noone has apparently stepped up to do it.
Not quite true.
Some time back (years), someone was working on an IDE interface for a
Qbus MicroVAX and I was doing the driver. (This was not bootable; the
idea was to netboot to get the kernel onto the machine.)
We never got it working, and it is not clear to me, now, why not. I'm
not sure whether this is because it wasn't clear why then or because my
wetware memory has bitrotted - what memory I have indicates that there
were hardware issues, but I had no physical access to the hardware, so
I'm not sure that that's right even aside from bitrotted memory. from the write addresses, even DEC did that with
interfaces.
It is otherwise straightfoward with the usual observance for timing and
the like.
Allison
I once was one of two people who built a one-off Qbus
board out of
wirewrap, so I feel I ought to be able to build such a thing myself.
Perhaps someday I'll gather the parts and try it. (Anyone have a Qbus
development board looking for a home? :)
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