To My Readers



If this is the first time you're visiting my blog, thank you. Whether you're interested or just curious to find out about PCB reverse engineering (PCB-RE), I hope you'll find something useful here.

This blog contains many snippets of the content in my books to provide a more detailed overall sampling for my would-be readers to be better informed before making the purchase. Of course, the book contains more photos and nice illustrations, as evidence from its cover page. Hopefully, this online trailer version will whet your appetite enough to want to get a copy for yourself.

Top Review

I started doing component level repair of electronics with (and without) schematics more than 40 years ago, which activity often involves reverse-engineering of printed circuit boards. Although over the years my technical interests have shifted into particle beam instrumentation, electron microscopy, and focused ion beam technology fields, till this day——and more often than not——PCB repairs have returned multiple multi-million-dollar accelerators, FIB, and SEM instruments back to operation, delivering great satisfaction and some profit.

Many of the methods described by Keng Tiong in great details are similar to the approaches I've developed, but some of the techniques are different, and as effective and useful as efficient and practical. Systematic approach and collection of useful information presented in his books are not only invaluable for a novice approaching PCB-level reverse engineering, but also very interesting reading and hands-on reference for professionals.

Focus on reverse engineering instead of original design provides unique perspective into workings of electronics, and in my opinion books by Keng Tiong (I've got all three of them) are must-read for anybody trying to develop good understanding of electronics——together with writings by Paul Horowitz and Winfield Hill, Phil Hobbs, Jim Williams, Bob Pease, Howard Johnson and Martin Graham, Sam Goldwasser, and other world's top electronics experts.

Valery Ray
Particle Beam Systems Technologist

Saturday, March 3, 2018

Emulating VAX/VMS on a PC

Test program development on the Factron Series-700 ATEs were carried out off-the-testers since test debugging was top priority with limited time slots and access to the hardware. With a strength of about 30 programmers during our peak, we did our work in front of VT220 and VT320 terminals at our desks.

These dumb terminals were networked to a DEC MicroVAX 360 server system running a Program Management System (PMS) that emulates the Factron's environment, where we:

1. Input board description, assigned component models from the standard libraries or wrote custom models that were not found,
2. Processed these PCB-related files to generate the wirelist and test program for the target tester,
3. Created in-circuit test routines (ICTRs) for devices without test, and
4. Compiled these ICTRs and then the main test program.

After all the pre-testing work was completed, a data package was then generated using GETPART for downloading from the target tester's terminal, so the programmer could then work on debugging the test program on a real board that was interfaced via an in-circuit fixture to the tester itself.

Overtime, maintaining and servicing the MicroVAX server become expensive and we started looking for an alternative to do away with the aging hardware which none but a few senior engineers knew how to operate. The VAX machine was reliable but not the hard disk, and though we frequently back up to tapes, finding replacement for the disks proved challenging as the available stocks diminished, mostly refurbished parts that had limited life-span anyway.

Fortunately, there were companies out there specializing in virtualization software that can emulate legacy VAX systems. After some evaluation, we engaged a company that helped us migrated the MicroVAX server to a Windows-based PC using the Charon-VAX solution. Of course, we paid quite a bit for the software license and service, but within three years it was recouped.

Now, after leaving my company, I still looked back fondly how I worked on the VAX environment. Is it possible to create my own virtual machine for VAX/VMS without having to pay a high price for the software license? I wondered. I soon found out that it was plausible indeed. Here is a screenshot of my very own VAX machine running the familiar VMS operating system within Windows 10:


The best thing is, I can customize it to look like the VT220 of the Factron DEC terminal and bring back some good memories. Like they say, good legacy software never dies; it just lives on in another hardware host that permits it to thrive in. Simply awesome!

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