Category: Hardware

It's not every day that a yet-unknown set of PC-family BIOS ROMs surfaces after 4 decades in obscurity. This one sure is strange, and seems to confirm accounts of a certain cancelled PC/AT prototype. It might also explain a bit of weirdness in some of IBM's published BIOS listings.

We've seen how the MC6845 CRTC can produce unintended, 'phantom' vertical sync pulses if R7 is re­written during active display time.  How about the HD6845?  Well, Hitachi's 6845 variant appears to be more sensitive, and will glitch in even more cases than its Motorola counterpart.

A dive into an obscure hardware glitch in the 6845 CRTC chip, which has to do with register rewriting, and only seems to really have a noticeable effect on IBM CGA boards (so far).  Let's see what it is, why it occurs, and how to avoid it.  There's bonus fractals, too!

CGA can output 16 digital RGBI colors, and there's a well-known standard palette which translates them to (s)RGB values - but that palette isn't a very good approximation of the colors you actually get on IBM's original CGA monitor.  Why is that, and can we do better?

Believe it or not, it's possible to transport ancient CRTs across continents, even with today's shipping services pulling out all the stops on incompetence.  Here's how an IBM Color Display was packed, shipped, and lived to tell the tale.

A fully-equipped IBM 5160 braves the rigors of international shipping and gets here in one piece (just barely).  As will be pictorially demonstrated, 30+ years after leaving the factory, this steel warrior is still one tough SOB.