Tony's kit, was: Re: USB Stuff

[Scott Stevens]

On Tue, 4 Oct 2005 21:14:57 +0100 (BST)
ard at p850ug1.demon.co.uk (Tony Duell) wrote:

> > 
> > Tony Duell wrote:
> > 
> > > Actually it doesn't. I am looking at a monochrome green screen at
> > > the moment. OK, I do have colour monitors around here....
> > 
> > I know I've asked this before but I don't recall the answer.  What 
> > exactly *do* you use to connect to the Internet?
> 
> I am sure I described it a couple of weeks ago here, and I've not 
> downgraded [1] since then
> 
> [1] That is, to sowmthing without schematics.
> 
> OK, here you are again : 
> 
> A much-hacked IBM PC/AT (8MHz system board). The mainboard has a 486 
> kludgeboard in the 80286 socket. I've added a couple of EPROMs and a
> bit of logic to overlay the last 8K of the bios, so I could modify the
> hard disk parameter table.
> 

There is a utility called 'hackrom' that I used to use to modify the
hard disk paramater tables on machines of that vintage.  The software
pulls a binary image of the BIOS out into a file, let you edit the
table, and split to odd/even, and burn back to ROMs to replace the
original.  You only had to open the case once to pull the stock ROMs and
plug in the new ones.  I used it one time to shoehorn in a 15 meg hard
drive on a '286 system.  You could basically 'replace' the parameters on
any table entry with your chosen new numbers.

Why did you need to add/overlay the BIOS to modify the parameter table?

> There's an original IBM MDA board linked to a 5151 greenscreen
> monitor. And a Colorgraph+ (Enhanced CGA card, with enough RAM for
> 640*200 in 8 colours, pity nothing supports it). That's linked to an
> NEC monitor that was used with an Apple ][, which I modifed to add the
> intensity line.
> 

Good choice in the MDA card.  Damned crisp characters and a rock steady
card.  I went for years with nothing more.  You don't have an IBM EGA
card for the color??