From: "Ralph Wade Phillips"
Subject: Re: ISA IRQ signal active how long?
Date: Sun, 6 Oct 2002 13:48:18 -0500
Organization: Phillips Enterprises
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"Michael A. Terrell" wrote in message
> Ralph Wade Phillips wrote:
> > "Keith R. Williams" wrote in message
> > news:MPG.firstname.lastname@example.org...
> > > I ranted about this before '81. I couldn't believe the PC
> > > designers made such a *stupid* mistake. Indeed this isn't the
> > > only transgression. The designers had no idea how to design with
> > > TTL.
> > Eh. The PC wasn't introduced until 1981. Late 1981, for that
> > matter. And that was with a (for IBM!) very short lead time - 6 months,
> > IIRC.
> > RwP
> Yes, but the ISA buss was a holdover from a word processing system
> based on the 8085 that used the same five slot case as the original PC.
> Remember the little metal door with a screw in the back that covered
> nothing? There was a battery there in the word processor. The video
> board and floppy drive controller board was the same in both systems. I
> scrapped several of the word processors, because no one wanted them.
> Now, i wish I still had one to show people where the PC came from.
The DisplayWriter was 8086 based, wasn't it? And the slot design
was different, IIRC.
The 8085 based unit was lower in the 5100 family - the 5110 or 5120,
IIRC. But those could have been IBM chips also. The PC used a LOT of
DisplayWriter designs in it, though.
Hmmm ... Might have to go digging back through the old Byte