Collaborate Disseminate
Today, most of what we think of as a computer uses digital technology. But that wasn’t always the case. From slide rules to mechanical fire solution computers to electronic analog computers, there have been plenty of computers that don’t work on 1s and 0s, but on analog quantities such as …read more
When it comes to reverse engineering silicon, there’s no better person to ask than Ken Shirriff. He’s the expert at teasing the meaning out of layers of polysilicon and metal. He’s reverse engineered the ubiquitous 555 timer, he’s taken a look at the inside of old-school audio chips, and he’s found butterflies in his op-amp. Where there’s a crazy jumble of microscopic wires and layers of silicon, Ken’s there, ready to do the teardown.
For this year’s talk at the Hackaday Superconference, Ken walked everyone through the techniques for reverse engineering silicon. Surprisingly, this isn’t as hard as it sounds. …read more
Continue reading Ken Shirriff Explains His Techniques For Reverse Engineering Silicon
Reverse engineering silicon is a dark art, and when you’re just starting off it’s best to stick to the lesser incantations, curses, and hexes. Hackaday caught up with Ken Shirriff at last year’s Supercon for a chat about the chip decapping and reverse engineering scene. His suggestion is to start with an old friend: the 555 timer.
Ken is well-known for his work photographing the silicon die at the heart of an Integrated Circuit (IC) and mapping out the structures to create a schematic of the circuit. We’re looking forward to Ken’s talk in just a few weeks at the …read more
Continue reading Ken Shirriff Chats About a Whole World of Chip Decapping
The IBM 1401 is a classic computer which IBM marketed throughout the 1960s, late enough for it to have used transistors rather than vacuum tubes, which is probably a good thing for this story. For small businesses, it was often used as their main data processing machine along with the 1403 printer. For larger businesses with mainframes, the 1401 was used to handle the slower peripherals such as that 1403 printer as well as card readers.
The Computer History Museum in Mountain View, CA has two working 1401s as well as at least one 1403 printer, and recently whenever the …read more
Continue reading Fixing An IBM 1401 Computer To Get It Printing Again
Most of us have been there. You build a device but realize you need two or more voltages. You could hook up multiple power supplies but that can be inconvenient and just not elegant. Alternatively, you can do something in the device itself to create the extra voltages starting with just one. When [Ken Shirriff] decapped an 8087 coprocessor to begin exploring it, he found it had that very problem. It needed: +5 V, a ground, and an additional -5 V.
His exploration starts with a smoking gun. After decapping the chip and counting out all the bond wires going …read more
In 1976, Texas Instruments came out with the TL084, a four JFET op-amp IC each with similar circuitry to Fairchild’s very popular single op-amp 741. But even though the 741 has been covered in detailed, when [Ken Shirriff] focused his microscope on a TL084, he found some very interesting things.
To avoid using acid to get at the die, he instead found a ceramic packaged TL084 and pried off the cover. The first things he saw were four stabilizing capacitors, by far the largest structures on the die and visible to the naked eye.
When he peered into his microscope …read more
Continue reading Ken Shirriff Found Butterflies In His Op-Amp
It must be everyone’s birthday today because [Ken Shirriff] has come out with a gift for us. He’s done another pass at reverse engineering the 76477 Space Invaders sound chip from the 1970s and found it’s full of integrated injection logic (I2L), making it a double treat: we get to explore the more of this chip which made sounds for so many of our favorite games, and we explore a type of logic which was to be the successor to TTL until CMOS came along.
This article has a similar shape to his last one, first introducing I …read more
Continue reading Space Invaders Sound Chip Went Old School With I2L
Lately, [Ken Shirriff] has been on some of the most incredible hardware adventures. In his most recent undertaking we find [Ken] elbow-deep in the core memory of a 50-year-old machine, the IBM 1401. The computer wasn’t shut down before mains power was cut, and it has refused to boot ever since. The culprit is in the core memory support circuitry, and thanks to [Ken’s] wonderful storytelling we can travel along with him to repair an IBM 1401.
From a hardware standpoint core memory makes us giddy. It’s a grid of wires with ferrite toroids at every intersection. Bits can be …read more
Continue reading [Ken Shirriff] Becomes a Core Memory Repairman (Again)
[Ken Shirriff] is no stranger to the pages of Hackaday. His blog posts are always interesting, and the recent one talking about the PocketBeagle is no exception. If you are old enough to remember the days when a Unix workstation set you back tens of thousands of dollars, you won’t be able to help yourself marveling at a Linux computer with 45 I/O pins, 8 analog inputs, 512K of RAM, and a 1 GHz clock, that fits in your pocket and costs $25. What’s more the board’s CPU has two 200 MHz auxiliary CPUs onboard to handle I/O without having …read more
In the real world, components don’t work like we imagine they do. Wires have resistance, resistors have inductance, and capacitors have resistance. However, some designers like to take advantage of those imperfections, something our old friend [Ken Shirriff] noted when he was restoring the CRT of a Xerox Alto.
[Ken] tried to connect a Xerox monitor to the Alto and — since it was almost as old as the Alto — he wasn’t surprised that it didn’t work. What did surprise him, though, is that when he turned the monitor off, a perfect picture appeared for just a split second …read more
Continue reading Xerox Alto CRTs Needed a Tiny Lightbulb to Function
