121
Reverse-engineering the first FPGA chip, the XC2064
A Field-Programmable Gate Array (FPGA) can implement arbitrary digital logic, anything from a microprocessor to a video generator or crypt...
Ken Shirriff
Computer history, restoring vintage computers, IC reverse engineering, and whatever
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Visit righto.com → RSS feedOn Hacker News Jul 2013 – Oct 2026
Hardware & Electronics 171History & Retro Computing 128Systems & Performance 21Software Engineering 10Crypto & Blockchain 9Security & Privacy 7
122
The Intel 8087 chip: floating-point addition and subtraction
In 1980, Intel introduced the 8087, a chip that made floating-point operations much faster in the IBM PC and other systems. Although the 808...
123
Inside the 8086 processor's instruction prefetch circuitry
The groundbreaking 8086 microprocessor was introduced by Intel in 1978 and led to the x86 architecture that still dominates desktop and se...
124
Reverse-engineering the division microcode in the Intel 8086 processor
While programmers today take division for granted, most microprocessors in the 1970s could only add and subtract — division required a sl...
125
A computer built from NOR gates: inside the Apollo Guidance Computer
We recently restored an Apollo Guidance Computer 1 , the computer that provided guidance, navigation, and control onboard the Apollo flight...
126
Reverse-engineering the 8086 processor's address and data pin circuits
The Intel 8086 microprocessor (1978) started the x86 architecture that continues to this day. In this blog post, I'm focusing on a small p...
127
The Z-80 has a 4-bit ALU. Here's how it works.
The 8-bit Z-80 processor is famed for use in many early personal computers such the Osborne 1, TRS-80, and Sinclair ZX Spectrum, and it is s...
128
The complex history of the Intel i960 RISC processor
The Intel i960 was a remarkable 32-bit processor of the 1990s with a confusing set of versions. Although it is now mostly forgotten (outs...
129
Reverse engineering the ARM1, ancestor of the iPhone's processor
Almost every smartphone uses a processor based on the ARM1 chip created in 1985. The Visual ARM1 simulator shows what happens inside the...
130
Reverse-engineering the Intel 8087's tangent algorithm: more than CORDIC
I hope you're not tired of the 8087, because I have another article about Intel's floating-point chip. 1 In 1980, Intel introduced the 8087...
131
Inside the 74181 ALU chip
What's inside a TTL chip? To find out, I opened up a 74181 ALU chip, took high-resolution die photos, and reverse-engineered the chip. 1 In...
132
Reverse engineering circuitry in a Spacelab computer from 1980
Spacelab was a reusable laboratory that could be carried in the cargo bay of the Space Shuttle, providing lab space for astronauts and exper...
133
The Texas Instruments TMX 1795: the first, forgotten microprocessor
The first 8-bit microprocessor, the TMX 1795 had the same architecture as the 8008 but was built months before the 8008. Never sold commerci...
134
Examining the core memory module inside a vintage IBM 1401 mainframe
The IBM 1401 mainframe computer was announced in 1959 and by the mid-1960s had become the best-selling computer , extremely popular with me...
135
Die analysis of the 8087 math coprocessor's fast bit shifter
Floating-point numbers are very useful for scientific programming, but early microprocessors only supported integers directly. 1 Although...
136
Reading a VGA monitor's configuration data with I2C and a PocketBeagle
Have you ever wondered how your computer knows all the characteristics of your monitor— the supported resolutions, the model, and even the...
137
Soyuz spacecraft digital clock teardown
We recently obtained a clock that flew on a Soyuz space mission. 1 The clock, manufactured in 1984, is much more complex inside than you'd ...
138
Die shrink: How Intel scaled down the 8086 processor
The revolutionary Intel 8086 microprocessor was introduced 42 years ago this month so I've been studying its die. 1 I came across two 8...
139
Reverse-engineering an unusual IBM modem board from 1965
The vintage IBM circuit board below has a large metal block on it that caught my attention, so I investigated it in detail. It turns out t...
140
IBM, sonic delay lines, and the history of the 80×24 display
What explains the popularity of terminals with 80×24 and 80×25 displays? A recent blog post " 80x25 " motivated me to investigate this. The ...
141
X-ray reverse-engineering a hybrid module from 1960s Apollo test equipment
In this blog post, I reverse-engineer a hybrid module that was used for ground-testing of equipment from the Apollo space program. But fir...
142
Restoring YC's Xerox Alto, day 1: Power supplies and disk interface
A few days ago, I wrote about how I'm helping restore a Xerox Alto for Y Combinator. This new post describes the first day of restoration...
143
Conditions in the Intel 8087 floating-point chip's microcode
In the 1980s, if you wanted your computer to do floating-point calculations faster, you could buy the Intel 8087 floating-point coprocessor ...
144
Restoring YC's Xerox Alto day 9: tracing a crash through software and hardware
Last week, after months of restoration, we finally got the vintage Xerox Alto computer to boot ( details ) and run programs. However, so...
145
Reverse-engineering precision op amps from a 1969 analog computer
We are restoring a vintage 1 computer that CuriousMarc recently obtained. Analog computers were formerly popular for fast scientific compu...
146
A database of SMS cards: The technology inside IBM's 1960s mainframes
IBM's mainframes of the 1960s are based on an interesting technology - Standard Modular System cards or SMS cards. These cards, created in ...
147
The unusual bootstrap drivers inside the 8086 microprocessor chip
The 8086 microprocessor is one of the most important chips ever created; it started the x86 architecture that still dominates desktop and ...
148
Reverse-engineering a mysterious Univac computer board
The IBM 1401 team at the Computer History Museum accumulates a lot of mystery components from donations and other sources. While going thr...
149
One-Hour Mandelbrot: Creating a Fractal on the Vintage Xerox Alto
I wrote a short program to generate the Mandelbrot set on the Xerox Alto, a groundbreaking minicomputer from the 1970s. The program, in...
150
How to run C programs on the BeagleBone's PRU microcontroller
This article describes how to write C programs for the BeagleBone's microcontrollers. The BeagleBone Black is an inexpensive, credit-card...