JRC-65 Computer

1. Introduction and Design Objectives
2. Clock Circuit

Tech Info

• Prototype Board
• IMSAI 8080 Replica
• Raspberry Pi Digital Clock
• Greaseweazle Floppy Controller
• Debian on an Asus Eee
• Gentoo on an Asus Eee
• Virtual Network Test Environment

NerdWorld Computer Museum

• Fuse Box circa 1910
• DEC PDP-8/I Replica
• IMSAI 8080 Replica
• Osborne 1
• TRS-80 Model 100
• Apple IIe
• IBM PC 5150
• Sharp EL-5400 Pocket Computer
• Macintosh SE
• HP 95LX Palmtop Computer
• HP Vectra VEi7 & OS/2 Warp
• IBM 340 & Windows 95
• Compaq Evo N400c & Windows 2000
• iMac 20"
• Eee PC Netbook

Essays

• Robert A. Heinlein: What I Believe
• Global Warming Fails the Smell Test
• The Speed of Light and Time Dilation
• Nattering Nabobs of Negativity
• Lessons of the Civil War

Links

• Links
• Lean Manufacturing

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The NerdWorld Report

Contents

JRC-65 Computer

A homebrew 6502 computer with LOTS of blinkin' lights.

Follow the design, breadboarding prototype, and building of a homebrew 6502 microcomputer. This system utilizes the venerable 6502 from the 1970/1980's and includes some modern components to enhance the functionality (like get internet and file access).

Critical to the design are LEDs on almost every address, data, and control line, as well as a variable clock so you can slow the computer down and really see what is happening on the CPU level.

Follow along at each stage of the design and construction as this system comes together. Photos and videos of the system as it takes shape and runs through tests.

Check back periodically as the process continues.

0. Introduction and Design Objectives (April 2024)
1. Clock Circuit Design (May 2024)

NerdWorld Computer Museum

My collection of vintage (and not-so-vintage) computers

Tech Info

• Prototyping Board (2025)



A robust prototype board that I will use to construct the prototype of the JRC-65 Computer.



• IMSAI 8080 Replica (2025)



An excellent replica of the first "Personal Computer" that actually looked like a computer. This one was immortalized in the movie WarGames.



• Raspberry Pi Clock (2025)



Use any old Raspberry Pi and an old monitor you've got lying around to make a nifty digital clock



• Greaseweazle Floppy Disk Controller (2025)



Read and write floppies for retro-computers such as the original IBM PC using this nifty device.



• Debian Linux on a Asus Eee (2011)



Ditch Windows and install Debian Linux on one of the original "netbook" computers. This article from 2011 details the trials, tribulations, and triumphs of making Debian Linux work on the Eee.



• Gentoo Linux on a Asus Eee (2012)



Ditch Windows AND Debian Linux and install compile-from-source-code Gentoo Linux on the Eee. Not for the faint of heart, this week+ effort took some work. See how it was done.



• Virtual Network test Environment (September 2024)



A virtual environment that I built to construct and test an eMail server. This setup can also be used to safely test any Internet-connected system.

Essays

• What I Believe, by Robert A. Heinlein (1952)



Robert A. Heinlein was one of the "grand masters" of Science Fiction. The author of Stranger in a Strange Land, Time Enough for Love, and Starship Troopers, he held strong beliefs and an undying faith in humanity to overcome adversity.

In this interview by Edward R Murrow for the radio program "What I Believe", Heinliein expresses his irrepressible faith in his fellow man.



• Global Warming Fails the Smell Test (2010)



An essay from 2010 about why I think Global Warming Climate Change^TM is bunk.

If it was "science", they would embrace skepticism instead of demonizing those who question it. And if it's a "existential threat" to humanity, why hasn't anyone turned off their air conditioner?



• The Speed of Light and Time Dilation (2010)



An essay about something that has confounded me for over 20 years.

To a "stationary" observer, time slows down when traveling close to the speed of light. But since speed is always measured relative to the Observer, why does the Traveler's clock slow down?

Doesn't the Traveler also think that it is the Observer's clock that slows?

I don't have a clue! Please read this and explain it to me!



• Nattering Nabobs of Negativity (2003)



An essay from 2003 about how the world is NOT getting worse, although all us old guys like to say it is.

The examples and data are a bit out of date, but I think the overall thesis is still valid. Sure, the world sucks, but it sucks less than it used to!

(The title comes from Vice President Spiro Agnew's famous complaint about how America's problems are magnified by the media.)



• Lessons of the Civil War (2004)



A discussion about the things I learned about politics and emotions from a very shallow dive into American history.

Who Is Casey Bralla?

I'm a recently retired Manufacturing Engineer who finally has the time to pursue some of my passions. See my Lean Manufacturing web site.

Have a question or wants some extremely-valuable free advice? I'd love to discuss your project with you. Call me or eMail me at the contact info above.