Raising the Bar for IBM PC/XT Emulation: MartyPC

Raising the Bar for IBM PC/XT Emulation: MartyPC

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This was publicly released over a month ago, so it's old news by now; but the IBM PC has waited over 4 decades to be emulated quite this faithfully, so what's a little holdup between friends?  MartyPC is the latest breakthrough in emulating the 5150 and 5160 - here's why I like it, and so will you.
More CGA CRTC Glitching: HD6845(R) vs. MC6845

More CGA CRTC Glitching: HD6845(R) vs. MC6845

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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.
Old Chips, New Glitches: the CGA/CRTC "Phantom" VSync

Old Chips, New Glitches: the CGA/CRTC "Phantom" VSync

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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!
The IBM 5153's True CGA Palette and Color Output

The IBM 5153's True CGA Palette and Color Output

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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?
About the PS/2 30-286's Hidden VGA Fonts

About the PS/2 30-286's Hidden VGA Fonts

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Another old riddle bites the dust: why did some 16-bit ISA PS/2 machines have an extra set of four alternate fonts tucked away in their firmware?  What on earth were those fonts good for?  And what's one thing you should never do when you're a PC developer 35 years ago?
Steel Survivor: an IBM XT Tale

Steel Survivor: an IBM XT Tale

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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.
Happy 35th birthday, IBM PC!

Happy 35th birthday, IBM PC!

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My present: 'Sorry Ass' - a 512-byte boot sector version of Bill Gates' DONKEY, the infamous demonstration game included with DOS and BASIC 1.0.
Olympiad: IBM Prototype Fonts Unearthed

Olympiad: IBM Prototype Fonts Unearthed

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Historical exhibit: a set of 25 floppy disks documenting IBM's creation of an in-house bitmap typeface for the RT PC project (code-named Olympiad).  Contains the original material as received, plus TTF and PNG conversions of the fonts and images.
So-called "IBM" Freeware Games from the Early '80s

So-called "IBM" Freeware Games from the Early '80s

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An archeological riddle: these very early public domain games all have similar title screens, which say "IBM" although they were clearly homebrew creations.  Where do they come from, who made them, and what is that cryptic "mystery code" all about?
101 Monochrome Mazes: Why Not Color?

101 Monochrome Mazes: Why Not Color?

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IBM officially discouraged PC programmers from exploiting hardware-specific tricks, since that came at the expense of compatibility.  Then, they went and released a game that did just that.  Here's why it was (artificially) prevented from running on color systems.