Ceci est une ancienne révision du document !
Q What is this Snappy thing I'm hearing about?
A A nice writeup is here: http://goo.gl/r7TU3b (That points to pcworld.com/article/2942267/why-ubuntu-plans-to-replace-traditional-linux-packages-with-something-better.html)
Q I wish to upgrade my Xubuntu 12.04 to Xubuntu 14.04. When I run the update manager, and hit the upgrade to 14.04 button, a window pops up and says: “Welcome to Ubuntu 14.04 'Trusty Tahr”
I don't want Ubuntu 14.04, I want only Xubuntu 14.04
A Go ahead, you will get Xubuntu 14.04. There are several places where Xubuntu is identified as “Ubuntu,” (eg. grub) and this is one of them.
Q I have a bunch of files in my Downloads folder with no extension. How can I determine what type of file they are?
A Use these two commands:
cd Downloads
file *
Q I added a 1 TB hard drive to my computer, but it does not show up in the file manager.
A You might need to install Gparted. Then run this command:
sudo gparted
In the top-right is a drop-down box to select a specific drive. Select your new drive. Then create one or more partitions, and format the partitions. The new partition(s) should appear in your file manager.
This process is actually a little bit simpler than the similar process under Windows.
Q My system was running when the power went off. Now it won't boot! It displays these error messages:
error : unknown filesystem. Entering rescue mode…
A (Thanks to oldfred in the Ubuntu Forums) Boot from a LiveCD or flash drive and run this command:
sudo e2fsck -f -y -v /dev/sda1
Q I'm having video playback problems on a low-powered system with Intel graphics.
A See this thread in the Ubuntu Forums: http://goo.gl/3TzD9y
On my Acer Aspire One, it didn't work a miracle, but it appeared to help.
Q I'm dual-booting with Windows 8, and Windows suffered a catastrophic failure. I thought I could just click on the partition from Ubuntu, and save a copy of my files. However, I get a long error message which includes this: “The NTFS partition is in an unsafe state.”
A (Thanks to grahammechanical in the Ubuntu Forums) The solution is spelled out in this article: http://goo.gl/dGjL4L (It's at webupd8.org/2015/06/workarounds-for-not-being-able-to-mount.html)
Q I am having trouble assigning a static IP address to my Ubuntu Server, which is connected to my router by an Ethernet cable.
A (Thanks to Chili555 in the Ubuntu Forums) Edit (sudo nano) /etc/network/interfaces as follows:
auto lo iface lo inet loopback auto eth0 iface eth0 inet static address 192.168.1.25 netmask 255.255.255.0 gateway 192.168.1.1 dns-nameservers 80.58.61.250 80.58.61.254
Then restart the interface:
sudo ifdown eth0 && sudo ifup -v eth0
To check it:
ifconfig
ping -c3 www.ubuntu.com
You will probably choose a different address and nameservers.
Top questions at Askubuntu
* How do I increase the number of lines shown on the Ubuntu terminal window? http://goo.gl/bA9XFB
* Keep /home directory when installing Ubuntu 14.04 http://goo.gl/hBcFaL
* Why does apt-get not require restarts, where the update manager does? http://goo.gl/T47YAe
* What kind of scheduling algorithms are used in 15.04? Is it possible to change it? http://goo.gl/ftMp2G
* How to get date and time using command line interface? http://goo.gl/iF1ft1
* How can I reliably check which is the last time an Ubuntu machine has been connected to the internet? http://goo.gl/q4U4xX
* How can I turn photos of paper documents into a scanned document? http://goo.gl/7cLJKV
* How to wipe a hard disk completely so that no data recovery tools can retrieve anything? http://goo.gl/T0nC40
* What happens if you Trash the Trash? http://goo.gl/eRoMJE
Tips and Techniques
A nostalgic time-sink
Issue 100 of Full Circle Magazine is coming up, which put me in a nostalgic mood. I'm sure I'm not the only person here who grew up in an IBM mainframe environment.
For those of us who are long in the tooth, April 7, 1964 was “the day the world changed.” Fortune Magazine called it “The $5 Billion Gamble,” as IBM announced System /360, which was supposed to combine scientific and commercial computing in a single box. (IBM's annual revenue at that time was about $5 billion, which made it by far the largest computing company.)
A few months later, I joined IBM, and a year later was assigned to help a customer use the initial release of OS/360. That was a horror show, but it got better. By release 16 it was quite solid.
It turns out that you can emulate that environment right on your own PC. The solution is in two parts. First, you need Hercules. “Hercules is an open source software implementation of the mainframe System/370 and ESA/390 architectures, in addition to the new 64-bit z/Architecture. Hercules runs under Linux, Windows (98, NT, 2000, and XP), Solaris, FreeBSD, and Mac OS X (10.3 and later).”
Then you need an operating system. There are several choices, older IBM operating systems including OS/360, DOS/360, DOS/VS, MVS 3.8, VM/370 and TSS/370, which are widely believed to be either public domain or “copyrighted software provided without charge.” The most popular is probably MVS (Multiple Virtual Storage,) which was an improvement over MVT, (Multiprogramming with a Variable number of Tasks). A lot of my early career was spent on MVT.
It's all available online for free. The operating systems include language compilers such as COBOL, but not CICS (Customer Information Control System), which was the most efficient way to set up online applications, or DB2.
It's tempting. COBOL was the first programming language which I felt I mastered. However, it's irrelevant to my life today, supporting users in an Active Directory environment. If I had a lot of time on my hands, I could certainly consume all of it, playing with my personal mainframe.