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ALTAIR 8800micro Build

9 Jul

ALTAIR 8800micro kit from Briel Computers


Setting up NI GPIB-USB-HS under Linux

26 Jul

Mostly stolen from:

Note unlike the ni_usb_b, this is the ni_usb_hs so no firmware has to be loaded at boot, thus gpib_config can be called directly.

Get latest source code

Typical build in /usr/local/src with
sudo make install

Edit configuration
sudo vi /etc/gpib.conf

board_type = "ni_usb_b"
name = "gpib0"

Add udev rules
sudo vi /etc/udev/rules.d/99-linux_gpib_ni_usb.rules

SUBSYSTEM=="usb", ACTION=="add", ENV{DEVTYPE}=="usb_device", ATTR{idVendor}=="3923", ATTR{idProduct}=="709b", MODE="660", GROUP="username", SYMLINK+="usb_gpib"
SUBSYSTEM=="usb", ACTION=="add", ENV{DEVTYPE}=="usb_device", ATTR{idVendor}=="3923", ATTR{idProduct}=="709b", RUN+="/usr/local/sbin/gpib_config"
KERNEL=="gpib[0-9]*", ACTION=="add", MODE="660", GROUP="username"

sudo udevadm control –reload-rules

Note udev will not run the gpib_config at boot, so add it in rc.local
sudo vi /etc/rc.d/rc.local

exit 0

sudo chmod +x /etc/rc.d/rc.local
sudo systemctl enable rc-local.service
systemctl status rc-local.service

Now plug in the adapter and run ibtest
Reboot and run ibtest

Linux Multimedia

19 Jul

Logitech C615 HD Webcam
sudo vi /etc/udev/rules.d/99-webcam.rules

SUBSYSTEMS=="usb", ATTRS{idVendor}=="046d", ATTRS{idProduct}=="082c", MODE:="0666"

sudo udevadm control --reload-rules

Dell XPS 13 Webcam
sudo vi /etc/udev/rules.d/99-webcam.rules

SUBSYSTEMS=="usb", ATTRS{idVendor}=="0bda", ATTRS{idProduct}=="5752", MODE:="0666"

sudo udevadm control --reload-rules

RPM Fusion Repository
sudo yum localinstall --nogpgcheck$(rpm -E %fedora).noarch.rpm$(rpm -E %fedora).noarch.rpm

GUVCView Webcam Recording
sudo yum install libwebcam guvcview

Change resolution to 1280×720 on XPS-13

Set sound device to hw:2,0 for Logitech webcam

Screen Recording
sudo yum install gtk-recordmydesktop

Set sound device to DEFAULT for Logitech webcam

May also need to use hw:0,0 (use arecord -l to list input devices)

Video Editing
sudo yum install openshot

Video Playback
sudo yum install vlc

Fedora 35 x86_64 Linux Install Notes

7 Feb

Hardware Configuration

sudo hostnamectl set-hostname tesla

Change to (e.g. runlevel 3)
sudo rm /etc/systemd/system/
sudo ln -s /lib/systemd/system/ /etc/systemd/system/

Change GRUB
sudo vi /etc/default/grub and remove rhgb quiet
sudo grub2-mkconfig -o /boot/grub2/grub.cfg

sudo dnf -y group install "Xfce Desktop"
touch ~/.xinitrc
echo "exec /usr/bin/xfce4-session" >> ~/.xinitrc

Network Config
IPV4: manual
IPV6: ignore

Update the System
sudo dnf update

<strong>Enable root Account
sudo passwd

Install Custom Shell Scripts
cp .bash_profile ~
cp .bashrc ~
cp .profile ~
cp .vimrc ~
sudo cp .bashrc /root

Directory Permissions
sudo chmod 777 /usr/local/src

Add Library Path to Linker
sudo vi /etc/
add /usr/local/lib
add /usr/local/lib64
sudo ldconfig

sudo /usr/bin/firewall-config
Change default zone to internal
Trust services as required

sudo dnf install system-config-printer
sudo system-config-printer

Search for network printer at
Use DirectJet port
Choose driver for Brother HL-5170DN
Use BR-Script3

sudo usermod -a -G audio username

The nm-applet gives insufficent permission errors when changing WiFi due to startxfce4 instead of using a display manager. This will fix it:

sudo vi /etc/polkit-1/rules.d/50-org.freedesktop.NetworkManager.rules
polkit.addRule(function(action, subject) {
if ("org.freedesktop.NetworkManager.") == 0 && subject.isInGroup("myusername")) {
return polkit.Result.YES;

(must reboot to take effect)

Apple II Floppy Drive Cable Retention Clamps

8 Jul

The Apple //e I recently acquired was missing the floppy drive cable retention clamps. As you can see from the manual pages, they retain the cable against accidental pulling, which could possibly break the floppy controller.



However they also reduce electromagnetic emissions (EMI). The ribbon cable has a copper braid, which I assume runs the length of the cable. It does not terminate on the floppy drive so it would serve no purpose other than EMI shielding, and to reduce coupling between adjacent wires. Nonetheless, the braid ought to be electrically bonded to the chassis, hence the need for the retention clamps.


I made the clamps out of 1/2″ x 3/32″ brass flat stock available at most hardware stores. It comes in a 12″ length for about $6. Take a sharpie and ruler, and mark off 2″ increments. Draw a centerline down the stock, then mark off 1/4″ from the each 2″ increment; this is where the holes will be drilled. Center punch the holes marks.

Drill 3/32″ holes for the back-plates and 1/8″ holes for the front plates. Tap the 3/32″ holes to 4-40 NC. Saw across the 2″ marks and file the edges smooth. Mark off a notch 1.2″ x 0.1″ on one long edge of each piece, then file the notch.


The drive cable lug will sandwich between the two pieces, which in turn will be held to the chassis with 4-40 x 1/2″ machine screws.






Apple IIe Unboxing

4 Jul

Found this Apple IIe, specifically a //e, on EBay. I normally would not purchase a system on eBay, however, this was a local seller so there was no shipping involved; cash and carry. The buy-it-now was $350 so I put in an offer for $150, which was accepted.

The system is in immaculate condition with the exception of the yellowing. No scratches or even dust. It was purchased from the original owner , a lady who bought I new, and from the looks of it, put it into storage after a few weeks. The peripherals came with the original boxes.

I ordered a Super Serial card on eBay for $10 which will allow me to bootstrap the machine to write disks from a modern PC. I’ll definitely be attending the vendor fair at KansasFest 2012 in hopes of finding a compact flash drive and a ROM upgrade.













Commodore 64 Setup

1 Jul

Ah, the treasures that await on Craigslist! Recently picked up a Commodore 64. Not sure if it was an impulse buy, since my wife was out of town and couldn’t veto it, or maybe trying to regain lost youth. I had one back in the day, however, I sold it to my high school electronics teacher. The only remaining item from my youth was a cartridge of Star Trek Strategic Operations Simulator, a port of awesome vector graphics arcade game. Anyway, I have been adding to the collection over the past few weeks, all vintage items found on KC Craigslist with the exception of the 1541 drive and Supergraphics printer adapter.

Commodore 64 console

Computermate keyboard cover

Commodore 1701 monitor with component video cable

Commodore 1541 floppy drive

Commodore 1530 Datasette

Panasonic KX-P1123 dot matrix printer

Xetec Supergraphics printer interface / buffer

TrippLite Command Console

Wico Command Control joysticks (qty 2)

Wico trackball

Comet 64 modem

EasyFlash 3

uIEC/SD flash drive

Zoom Floppy controller

Flyer Internet Modem