Category Archives: Software

Keyboard scanning on the DIY4

Posted on July 25, 2011 by Eric

I tracked down a bug in the keyboard scanning of the DIY4 today. I thought there needed to be a delay in the scan routine between writing the scan lines and reading the return lines, but it turns out that … Continue reading →

Posted in Calculators, Hardware, RetroChallenge, Software | Leave a comment

Bit-banging FRAM on the DIYRPN 4

Posted on July 25, 2011 by Eric

I’ve written code that successfully reads the vendor/device ID and serial number from a Ramtron FM25VN10 SPI FRAM chip. I haven’t yet read or written data. The code is currently using GPIO bit-banging, but the hardware is designed to allow … Continue reading →

Posted in Calculators, Hardware, RetroChallenge, Software | Leave a comment

HP-41 card reader bug

Posted on July 25, 2011 by Eric

It occurred to me while studying simulator traces that it might be interesting to investigate a bug in early versions of the 82104A card reader for the HP-41C calculator. The bug was fairly esoteric and easily avoided, as it seemed … Continue reading →

Posted in Calculators, Nonpareil, RetroChallenge | 2 Comments

HP-41CV ROM set version HFF bug fix

Posted on July 25, 2011 by Eric

As I was studying HP-41CV microcode running in simulation, I finally uncovered what one of the bug fixes in the HFF ROM version does. This has been a mystery for many years, though there’s still one more unexplained change relative … Continue reading →

Posted in Calculators, Nonpareil, RetroChallenge | Leave a comment

misc. hints on debugging Linux power management

Posted on June 8, 2011 by Eric

Dump BIOS DMI table: dmidecode Dump devkit power status:  devkit-power –dump or upower –dump Enable power manager debugging, useful before suspend:  echo 1 >/sys/power/pm_trace look at log file: /var/log/pm-suspend.log

Posted in Fedora, Linux | Leave a comment

misc. Linux notes

Posted on June 8, 2011 by Eric

Things I’ve learned today that I’ll probably need to know later, after I’ve had a chance to forget them: GNOME 3 was designed by idiots for idiots.  They’ve tried to make it completely drool-proof, and in the process made it … Continue reading →

Posted in Fedora, Linux | 1 Comment

USB tethering an Android phone to an OpenWRT router

Posted on July 21, 2010 by Eric

Now that I’ve got OpenWRT 10.03 “Backfire” running on my DIR-825, I decided to take advantage of the new USB tethering feature of Android 2.2 “Froyo”.  I connected my Nexus One phone to the USB port of the DIR-825, and … Continue reading →

Posted in Android, OpenWRT | 8 Comments

Installing OpenWRT 10.03 “Backfire” on a DIR-825

Posted on July 21, 2010 by Eric

I did a fresh install of the jffs2 build of Backfire on a D-Link DIR-825.  I could have used the squashfs version, and have done that in the past, but using the jffs2 build makes it easier to use an … Continue reading →

Posted in OpenWRT | 1 Comment

Suboptimal Multimedia Player Software

Posted on September 26, 2009 by Eric

I’m trying to watch a recorded event for a class. Unfortunately it is provided as a streaming .ram file, which means that RealPlayer is basically my only option for watching it. While I have a high-bandwidth internet connection, RealPlayer was … Continue reading →

Posted in School & Education, Software, The Suboptimal Way | Leave a comment

More trouble with Radeon HD 2600 Pro AGP

Posted on September 18, 2009 by Eric

When I posted Dual Head on Fedora 11 last night, I thought I had the problem completely solved, but when I booted the system this morning, the video card was acting up again.  There were lots of black horizontal streaks … Continue reading →

Posted in Fedora, X11 | Leave a comment