91
Reverse Engineering the Constants in the Pentium FPU
Intel released the powerful Pentium processor in 1993, establishing a long-running brand of high-performance processors. 1 The Pentium incl...
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
92
An unusual 7400-series chip implemented with a gate array
When I look inside a chip from the popular 7400 series, I know what to expect: a fairly simple die, implemented in a straightforward, cost-e...
93
Extracting ROM constants from the 8087 math coprocessor's die
Intel introduced the 8087 chip in 1980 to improve floating-point performance on the 8086 and 8088 processors, and it was used with the ori...
94
Restoring YC's Xerox Alto: how our boot disk was trashed with random data
In the previous Xerox Alto restoration session , we got the disk working, but the system didn't boot. After much investigation, I discove...
95
The Intel 8086 processor's registers: from chip to transistors
The Intel 8086 microprocessor is one of the most influential chips ever created; it led to the x86 architecture that dominates desktop and...
96
Interesting double-poly latches inside AMD's vintage LANCE Ethernet chip
I've studied a lot of chips from the 1970s and 1980s, so I usually know what to expect. But an Ethernet chip from 1982 had something new: a ...
97
Simulating the IBM 360/50 mainframe from its microcode
The IBM System/360 was a groundbreaking family of mainframe computers announced on April 7, 1964. System/360 was an extremely risky "bet-t...
98
Macbook charger teardown: Complexity inside Apple's power adapter (2015)
Have you ever wondered what's inside your Macbook's charger? There's a lot more circuitry crammed into the compact power adapter than you...
99
Strange chip: Teardown of a vintage IBM token ring controller
IBM used some unusual techniques in its integrated circuits, and one of the most visible is packaging them in square metal cans. I've been...
100
How flip-flops are implemented in the Intel 8086 processor
A key concept for a processor is the management of "state", information that persists over time. Much of a computer is built from logic gate...
101
Silicon die teardown: a look inside an early 555 timer chip
If you've played around with electronic circuits, you probably know the 555 timer integrated circuit, 1 said to be the world's best-selli...
102
Inside a 20-Watt Traveling Wave Tube Amplifier from Apollo
How did the Apollo astronauts communicate on their trip to the Moon, 240,000 miles back to Earth? They used a 32-pound amplifier, built ar...
103
Reverse engineering the Intel 386 processor's register cell
The groundbreaking Intel 386 processor (1985) was the first 32-bit processor in the x86 line. It has numerous internal registers: general-pu...
104
Repairing a 1960s mainframe: Fixing the IBM 1401's core memory and power supply
A few weeks ago, I wanted to use one of the vintage IBM 1401 mainframe computers at the Computer History Museum, but the computer wasn't wor...
105
A one-bit processor explained: reverse-engineering the vintage MC14500B
The Motorola MC14500B 1 is a 1-bit processor introduced in 1976. While a 1-bit processor might seem almost useless, 2 it was marketed as...
106
Bitcoin mining the hard way: the algorithms, protocols, and bytes
This article explains Bitcoin mining in details, right down to the hex data and network traffic. If you've ever wondered what really happe...
107
Reverse-engineering the conditional jump circuitry in the 8086 processor
Intel introduced the 8086 microprocessor in 1978 and it had a huge influence on computing. I'm reverse-engineering the 8086 by examining t...
108
How the Z80's registers are implemented
The 8-bit Z80 microprocessor is famed for use in many early personal computers such the Osborne 1, TRS-80, and Sinclair ZX Spectrum. The Z80...
109
Yamaha DX7 reverse-engineering, part III: Inside the log-sine ROM
The Yamaha DX7 digital synthesizer (1983) was the classic synthesizer for 1980s pop music. It used two custom digital chips to generate so...
110
Inside a Ferroelectric RAM Chip
Ferroelectric memory (FRAM) is an interesting storage technique that stores bits in a special "ferroelectric" material. Ferroelectric memory...
111
The stack circuitry of the Intel 8087 floating point chip, reverse-engineered
Early microprocessors were very slow when operating with floating-point numbers. But in 1980, Intel introduced the 8087 floating-point copro...
112
Repairing the card reader for a 1960s mainframe: cams, relays and a clutch
I recently helped repair the card reader for the Computer History Museum's vintage IBM 1401 mainframe. In the process, I learned a lot abou...
113
The adder at the heart of Intel's 8087 floating-point chip
In 1980, Intel released the Intel 8087 floating-point coprocessor, a chip that could make math up to 100 times faster. As well as arithmetic...
114
Fixing the Ethernet Board from a Vintage Xerox Alto
A Xerox Alto system on the East coast had Ethernet problems, so the owner sent me the Ethernet board to diagnose. (After restoring our Alto,...
115
An 8-tube module from a 1954 IBM 705 mainframe: it's a key debouncer
IBM's vacuum tube computers of the 1950s were built from pluggable modules, each holding eight tubes and the associated components. I recent...
116
Reverse-engineering a vintage power supply chip from die photos
I recently did a PC power supply teardown so I figured it would be interesting to go deeper and see what happens inside the power supply'...
117
Why the Z-80's data pins are scrambled
If you look closely at the datasheet for a Z-80 chip, you'll notice the data pins are in a random-looking order. The address pins (A) are ni...
118
Bitcoin transaction malleability: looking at the bytes
"Malleability" of Bitcoin transactions has recently become a major issue. This article looks at how transactions are modified, at the byte...
119
Teardown of a quartz crystal oscillator and the tiny IC inside
The quartz oscillator is an important electronic circuit, providing highly-accurate timing signals at a low cost. A quartz crystal has the...
120
A look inside the chips that powered the landmark Polaroid SX-70 instant camera
The revolutionary Polaroid SX-70 1 camera (1972) was a marvel of engineering: the world's first instant SLR camera. This iconic camera wa...