Insanity 4004

One of the most common questions I get from people is "Can I put the ESDI-Emu in my PS/2 Models 50/55/70?"

For the last few years I've volunteered at the System Source Computer Museum.

When I last wrote in this blog last December I'd just completed Lesson 2 of FEDEVEL's "Advanced PCB Layout" course.

I finished Lesson 2 of FEDEVEL Academy's Advanced PCB Layout course yesterday.

As part of a hobby project I'm designing a PCB that will include a Xilinx Zynq-7000 System-on-Chip and a DDR3L SDRAM.

I've been doing a lot of work recently with vintage PC disk storage subsystems.

Here's what I'm currently working on restoring for the System Source Computer Museum: Yes, this is an IBM System/360 Model 20 from the mid 1960s.

Okay, so it's been 5 months since I updated this blog.

Any time you're working with older electronics, there's a risk that some of the components may have failed as a result of age.

Since the Soroban Computeriter is entirely electro-mechanical, I expected everything to operate glacially slowly.

As described here, the System Source Computer Museum asked me to build an electronic replacement for the non-repairable Soroban Computeriter used with the recently-acquired CDC 160A computer.

This drawing from the Soroban Computeriter Coder Unit Technical Manual shows the underside of the Computeriter.

In the early 1960s a company called Soroban Engineering produced a product they called a Computeriter.

Last summer I came across my somewhat tattered copy of the PDP-11 Processor Handbook.

I decided today was a good day to populate the Arithmetic Logic Unit board I had fabricated in March.

My project for April and May was to extend my PicoBlaze-based test framework to test the Instruction Pointer board I built in 2012.

You know what the most costly phrase you can say is?

The skillet I bought is a Farberware 12" x 12" ceramic skillet, model FW6110027877.

My JLCPCB order containing both the Arithmetic Logic Unit and Instruction Decoder boards arrived Thursday afternoon, nine days after I submitted the Gerber files.

In a comment on my post How high and how fast?

I started laying out the Instruction Decoder board in late November 2012, and started the Arithmetic Logic Unit board ten days later.

Most of the circuitry in the 4004 CPU and other MCS-4 family chips uses a MOSFET to actively pull a signal toward Vss, and a "load" to passively pull it back toward Vdd.

Here's the Arithmetic Logic Unit board: All nets have been routed, and the design rule checks run without error.

Here it is, the (hopefully) final layout of the Instruction Decoder board: Like the previous two and several to follow, this board uses stacking connectors to make the connections between it and the other boards that make up the i4004 CPU.

A couple of days ago I "finished" routing the Instruction Decoder board.

When I started my efforts to construct a discrete-component replica of an Intel 4004 CPU in June of 2012, I realized that I was going to have to split the CPU into several parts.

In addition to a 40-year career as a software engineer specializing in operating systems, I've also managed corporate and personal computer systems.