Skip to content

What Xerox PARC was really "worth"

Here is an interesting read about what Xerox PARC was really "worth". I often have the feeling that large corporations don't see the value in real invention anymore, but are only on the lookout for "innovative companies" to buy and squeeze out. Which may work for a short term to raise revenue and profit, and thus the share price - until this company has been assimilated, talent has drained to other companies, and a new one needs to be bought. Continue reading "What Xerox PARC was really "worth""

Linux remote login

For really a long time I have used a really nice feature of the X11 windowing system - remote login. That was rather easy to do. Just enable XDMCP and connecto to the X server remotely. It was not safe over the networks, but I used it only locally. My main use case was and is using the main PC in my home office from other places.

Now for a few releases the Linux distributions started to disable the protocol, or at least make it more complicated to use, as XDMCP isn't supported in the admin tools anymore.
Continue reading "Linux remote login"

The anatomy of a microbenchmark

Almost two years ago I demonstrated a 10MHz accelerator card for the Commodore PET on the Classic Computing exhibition. For this presentation I wrote a small demo program that draws a 3-D cube on the PET's screen - first with 1 MHz, then with 10 MHz. As I was concentrating on the 10MHz speedup, I didn't have enough time to look deeply into the demo program itself. So it was questioned why it was so slow in 1MHz compared to other demos. Finally I found the time to have a look at this, so I'll make this an example of a performance optimization job. Read on to learn about how the proper approach for a performance optimization even helps fixing performance problems in an old Commodore BASIC program.

Continue reading "The anatomy of a microbenchmark"

The XD2031 architecture explained

Recently I have written about refactoring a 20 year old code base, namely of the file system server code for my old Commodore computers (see here: Refactoring-20-year-old-code... ). Here is a description of the internal structure of that code. I do this description in the form of an "architecture overview", a form that I think is missing for many a software project. Continue reading "The XD2031 architecture explained"

Refactoring 20 year old code...

When I was working on my selfbuilt 6502 operating system, I had a file system server on the PC, connected to the 6502 via a serial line (RS232). It was using a generic, packet-based protocol on the serial "wire", so I decided to reuse the protocol and the server for an AVR-based implementation of a Commodore disk emulator. The Commodore would talk to the AVR via IEEE488 or the CBM serial IEC protocol, which would behave as a disk drive and use the wire protocol to talk to the PC to server files from there. In the beginning it looked like a good idea. But it took much more time than expected. Read on for the full story.
Continue reading "Refactoring 20 year old code..."