Linux: Quick multiple page scanning with scanimage
It’s often required to scan a lot of pages in one go, even manually. The problem is that when doing individual scans, there’s a significant delay between each scans, as the computer initializes the...
View ArticleSample EDID info from a few monitors (video resolution parameters)
On Linux machines, there’s a command saying $ xrandr --verbose which outputs a lot of information about the display, in particular the EDID information obtained from the monitor. Among others, it’s a...
View ArticlePlaying with Linux namespaces
Intro Linux namespaces is the foundation for container-based virtualization, which is becoming increasingly popular. Aside from the ability to isolate a shell (and the processes it generates) from the...
View ArticleIssue with making a bootable Ubuntu 15.04 USB stick
I wanted to create a boot USB stick from an Ubuntu 15.04 desktop that was running in a Virtual machine. So I plugged in a clean USB stick, and picked “Startup Disk Creator” from the Launcher. Then...
View ArticleLinux: Yet Another Google Chrome “Aw, snap” solved.
“Aw, snap” in Google Chrome happens when a process (or thread?) involved with Chrome dies unexpectedly. I got quite a few of those, and learned to live with them for about a year, as I couldn’t figure...
View ArticleInstead of using “rm -rf”
The slightly safer alternative is $ rm --one-file-system -vrf delme-junk/ There are two additional flags: The -v flag causes “rm” to display the files as it deletes them. This gives the user a chance...
View ArticleLinux kernel compilation jots
Just a few notes to self as I compiled a kernel on a x86_64 machine, targeting an i386. Kind-of cross-compilation, but with no need for a cross compiler. Remember to update the (extra) version number...
View ArticleHexdump notes
General notes For plain byte-per-byte hex dump, $ hexdump -C To dump a limited number of bytes, use the -n flag: $ hexdump -C -n 64 /dev/urandom 00000000 9c 72 b0 43 da 6e 27 2f f9 f1 34 06 60 d5 71...
View Articlesyslogd notes
A few jots on playing with the system logger (the one that writes to /var/log/messages) on an ancient CentOS 5.5. First, check the version: It says Oct 6 15:12:06 diskless syslogd 1.4.1: restart. So...
View ArticleLinux kernel hack for calming down a flood of PCIe AER messages
While working on a project involving a custom PCIe interface, Linux’ message log became flooded with messages like pcieport 0000:00:1c.6: device [8086:a116] error status/mask=00001081/00002000 pcieport...
View ArticleUsing Linux’ setpci to program an EEPROM attached to an PLX / Avago PCIe switch
Introduction These are my notes as I programmed an Atmel AT25128 EEPROM, attached to a PEX 8606 PCIe switch, using PCIe configuration-space writes only (that is, no I2C / SMBus cable). This is frankly...
View ArticleCursor control characters in a bash script
To control the cursor’s position with a plain bash “echo” command, use the fact that the $’something‘ pseudo-variable interprets that something more or less like a C escape sequence. So the ESC...
View ArticleReading the firmware ROM from a Renesas uPD720202 USB 3.0 Host Controller...
Pretty much as a side note, I should mention that the firmware should and can be loaded with a Windows utility named K2024FWUP1.exe. Get it from whereever you can, and verify it isn’t dirty with $...
View Articlesystemd jots
I not an expert on this These are just my what-on-earth-is-going-on-here notes as I tried to understand how my Debian 8.2 (“Jessie”) machine boots up. Conclusion: It’s a mess. More specifically, it’s a...
View ArticleLVM volume resizing jots
These are my jots as I resized a partition containing an encrypted LVM physical volume, and then took advantage of that extra space by extending a logic volume containing an ext4 file system. The...
View ArticleLinux Malware Detect for occasional non-root use
Intro This is a minimal HOWTO on installing Linux Malware Detect for occasional use as a regular non-root user. Not that I’m so sure it’s worth bothering, given that contemporary exploit code seems to...
View ArticlePassword-less SSH remote login demystified
This is documented everywhere, and still, I always find myself messing around with this. So once and for all: The files In any user’s .ssh/ directory, there should be (among others) two files: id_rsa...
View ArticleUnder the hood of Vivado runs: Some scripting essentials
Introduction My motivation for looking inside Vivado runs was that I wanted to implement a Vivado project from within XEmacs, using the Compile button, and all that within a rather tangled...
View Articlechroot and dynamic libraries: Some jots
This is just a messed up pile of jots as I tried to solve a specific problem. The actual problem turned out to be between chair and keyboard, but I decided to post this anyhow, just in case it will be...
View ArticleWhere to find “Recent Documents” in Fedora 12
Short answer: ~/.recently-used.xbel (taken from here, and it actually works on my computer). It’s an XML files, organized in chronological order, last item most recently accessed. It was moved into...
View Article