Tag Archives: computer design

Back in the U.S.

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If you sense a dearth of recent posts, you’re right. February and March have been insanely busy, including two long trips. The first trip took us to Seattle to see our grandson who grows by leaps and bounds every day. The second trip was to South Africa where we married off our nephew and welcomed a wonderful South African lass into our extended family.

Naturally, computer science and history always lurk in the background, occasionally coming center stage. In February, I completed a second donation to Living Computers in Seattle. I donated two working Atari computers (a 400 and an 800XL) to their collection. Everything went — peripherals, joysticks, touch pad, and software. I played a few rounds of Missile Command, etc. before sending off the entire lot. I can’t believe that I spent hours (days!) playing F-15 Strike Eagle with its cheesy graphics. 🙂 If you want to play old Atari machines and much more, please visit. You’ll have a good time!

Right on the heels of the donation, we stopped into Living Computers for a visit. We had a fun chat with Aaron Alcorn who is the Museum’s curator. He let us in about some of the Musuem’s plans as well as swapping photos of our kids (and grandkid). We saw our donated — now theirs — Apple Performa 6400 VEE in the second floor workshop/open storage. The Museum is planning a major exhibit for that space. (Restoration of an historically important mainframe. Stay tuned.)

After a few brief weeks at home, we took off for South Africa via London. Our original itinerary allowed for a day trip to Bletchley Park and the The National Museum of Computing. Unfortunately, the plan was dashed by the weather. A nor’easter hit Boston on the departure date and we had to shorten our stay in London to an over-nighter.

Nonetheless, we walked over to London’s Science Museum on Exhibition Road, bagging yet another science museum in yet another city. (We also wanted to see how many holes it took to fill the Albert Hall.) The mathematics and information age exhibits helped to make up for losing Bletchley Park.

The Science Museum has an excellent collection of mechanical computing devices including Charles Babbage’s analytical engine (trial model, 1871). It took a little digging to find any reference to Lady Ada Lovelace whose contributions, I dare say, were longer-lasting than Babbage’s. Mechanical computing engines precede electronic computing, using physical machines (or even water flow!) to model other real-world phenomena by mathematical analogy. These devices, including so-called analog computers, filled the need for high(er) speed computation before digital computing really took wing. (By the way, electronic analog computing seems underrepresented at both the Science Museum and Living Computers. Just sayin’.)

My photography skills and the iPod camera were not up to snuff. I had hoped to include many images here. However, we did see quite a number of historically significant machines: Hollerith card sorter, EDSAC-1, Pilot ACE, LEO II, Besem-6, Newton Clamshell, Xerox PARC Alto, and early PDP-8 among the finds. A number of machines/artifacts are on loan from the Computer History Museum in Mountain View, California. (Not far away from where I once lived, BTW.)

Seeing the PDP-8 in a glass case at the Science Museum, really made me “get” the concept behind Living Computers. Here was a poor old machine trapped in a glass cage. At Living Computers, you can use a PDP-8! This isn’t meant to be a slam on the Science Museum because preservation of early computing artifacts is incredibly important, especially in a society and culture which is all too willing to throw away the last generation of shiny thing. It does highlight the unique aspect and mission of Living Computers: Museum + Labs. Please join and visit.

Copyright © 2018 Paul J. Drongowski

Welcome CS teachers and students!

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[Be sure to visit Living Computers in Seattle. SIGCSE 2017 attendees are admitted free during the conference. I visited the museum today and it was a lot of fun! K-12 teachers will enjoy the hands on exhibits.]

The annual ACM Special Interest Group on Computer Science Education (SIGCSE 2017) Technical Symposium is next week (March 8 – 11) in Seattle, Washington. The symposium brings together educators at all levels (K-12 and higher ed) to exchange and discuss the latest methods, practices and results in computer science education.

I don’t often advertise it, but the Sand, Software, Sound site has many resources for educators and students alike. You can browse these resources by clicking on one of the WordPress topic buttons (Raspberry Pi, PERF, Courseware, etc.) above. You can also search for a topic or choose from one of the categories listed in the right sidebar.

Here are a few highlights.

I taught many computer-related subjects during my career and have posted course notes, slides and old projects. The four main sections are:

  • CS2 data structures: Undergraduate data structures course suitable for advanced placement students.
  • Computer design: Undergraduate computer architecture and design which uses a multi-level modeling approach.
  • VLSI systems: Graduate course on VLSI architecture, design and circuits which is suitable for undergraduate seniors.
  • Topics in computer architecture: Material for a special topics seminar about computer architecture (somewhat historical).

Please feel free to dig through these materials and make use of them.

Software and hardware performance analysis formed a major thread throughout my professional life. I recommend reading my series of tutorials on the Linux PERF tool set for software performance analysis:

The ARM11 microarchitecture summary is background material for the PERF tutorial. Program profiling is a good way to bring computer architecture to life and to teach students how to analyze and assess the execution speed of their programs.

There are two additional tutorials and getting started guides for teachers and students working on Raspberry Pi:

Music technology and computer-based music-making have been two of my chief interests over the years. The Arduino section of the site has several of my past projects using the Arduino for music-making. You should also check out my recent blog posts about the littleBits synth modules and littleBits Arduino. Please click on the tags and links at the bottom of each post in order to chase down material.

You might also enjoy my tutorial on software synthesizers for Linux and Raspberry Pi. The tutorial is a getting started guide for musicians of all stripes — music teachers and students are certainly welcome, too!

Wanna design a computer?

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The next installment in the courseware section — computer design — is now available.

This course shows how to design a computer starting with an abstract specification of the instruction set architecture (ISA) and ending with a gate-level implementation. The course teaches a method which successively translates a higher-level representation for the machine into a lower-level representation. For example, the ISA is translated to a datapath consisting of large-grain building blocks and a control graph annotated with register transfer statements. Then, the datapath and control graph are mapped into gate-level building blocks and control store. Different datapath and control styles (clocking, pipelining and microprogramming) are discussed. Computer science students should be comfortable with the representations — no scary electronics.

I taught this course for several years at Case Western Reserve University. It’s an undergraduate level course that assumes a prerequisite course in basic logic design. So, if you already know about gates, flip/flops and simple sequential logic, you’re ready to dive right in! Course material includes draft chapters for a book on computer design and slides.

I hope that you will be able to use this course for background knowledge once I begin to experiment with and write up Papillio projects. I would probably base class projects on Xilinx FPGAs (Papillio) if I were teaching this course today. Papillio makes hardware design personal and affordable. I would love to see more computer science students take up hardware design, especially in high school. Perhaps this course will help you out.