Open Hardware: Raspberry Pi, Retro, and More
-
Optimising Raspberry Pi 5’s software environment
In this latest addition to our Raspberry Pi 5 development diary, Principal Software Engineer Tim Gover joins Gordon Hollingworth and Eben to discuss how we developed Raspberry Pi 5’s software environment.
-
The Datassettes
It works like this: During recording, the tape head creates a small but strong magnetic field while the tape is moving past it at a constant speed. When current passes through the tape head in one direction, the magnetic particles on the tape orient themselves one way, and when current passes in the other direction they orient themselves the other way. During playback no current is driven through the tape head. Instead, as the tape moves, its particles create a weak magnetic field around the tape head. When there's a change in this field—because the particles on the tape are suddenly oriented the other way—a small spike of electric current is induced in the tape head. This spike is sensed and amplified. Thus, the time between polarity swaps during recording corresponds to the time between spikes during playback, and this series of timestamps is used to encode information.
-
Examining the silicon dies of the Intel 386 processor
You might think of the Intel 386 processor (1985) as just an early processor in the x86 line, but the 386 was a critical turning point for modern computing in several ways.1 First, the 386 moved the x86 architecture to 32 bits, defining the dominant computing architecture for the rest of the 20th century. The 386 also established the overwhelming importance of x86, not just for Intel, but for the entire computer industry. Finally, the 386 ended IBM's control over the PC market, turning Compaq into the architectural leader.
In this blog post, I look at die photos of the Intel 386 processor and explain what they reveal about the history of the processor, such as the move from the 1.5 µm process to the 1 µm process. You might expect that Intel simply made the same 386 chip at a smaller scale, but there were substantial changes to the chip's layout, even some visible to the naked eye.2 I also look at why the 386 SL had over three times the transistors as the other 386 versions.3
-
What counts as authentic retrocomputing
I think we’d all agree that classic hardware would be more fun if you have the money and space, but someone learning 6502 assembler in an emulator on a modern machine is still performing an art that people in the 1980s did. It’s also the worst kept secret in retrocomputing that most modern classic games are written on contemporary hardware, just as people weren’t necessarily developing software for these systems on those systems at the time.
-
Close To The Metal
Firmware is caught between hardware and software. What do I mean? Microcontroller designers compete on how many interesting and useful hardware peripherals they can add to the chips, and they are all different on purpose. Meanwhile, software designers want to abstract away from the intricacies and idiosyncrasies of the hardware peripherals, because code wants to be generic and portable. Software and hardware designers are Montagues and Capulets, and we’re caught in the crossfire.