Things that make Go channels expensive to implement
Recently, fchan : Fast Channels in Go made the rounds ( via ).I read it with some interest, because I'm always interested ininteresting high-performance concurrent things like this, but my firstreaction was that they'd started with an artificially inexpensivescenario. That got me thinking about what features make Go channelsexpensive (ie slower), regardless of the specifics of the implementation.
Generally, what makes concurrent operations intrinsically expensiveis the need for cross-thread locking and coordination. So we can
I think docstrings in Python are for everything, not just public things
In my entry on my mixed feelings about docstrings , I mentioned that my most recent Pythoncode was all comments and no docstrings, but also that it was aprogram instead of a module. So here's a question: should thatmatter for whether or not you use docstrings? The obvious relatedquestion is whether docstrings are for documenting everything in amodule, or only the things people are supposed to use.
My best current answer is that if you're going to use docstrings atall, I think that
Linux desktops and pre-packaged machines from big vendors
Today, I tweeted :
I wonder if Dell or any of the big vendors makes reasonably-priced(mid-)tower systems with 4 3.5" drive bays and 32 GB of RAM.
There is a story behind this tweet, and it's in part a story of howfar Linux has come over the time I've been using it.
For a long time, the only way to get a decent Linux (desktop) machinewas to specify it from parts yourself. If you were
My still-mixed feelings about Python's docstrings
I've written before about why I'm not really fond of docstrings in Python. I continueto feel that way, but at the same time I have to acknowledge thatthe Python world has made its decision; although help() et alhave some heroic hacks to deal with documentation comments , the only fully supported in-Python way to documentyour module for other people is with docstrings.
This doesn't mean that docstrings are the best way to document yourmodules. Python's own module documentation
An Ubuntu default Bash setup that irritates me, especially for root
Bash itself has a number of option settings to limit what it puts intothe (interactive) command history list, such as $HISTCONTROL and $HISTIGNORE . A stock, no-startup-file Bash shell does not set anyof them and so saves everything into the history list. However, manysystems give you a default .bashrc file that sets some options here.In particular, Ubuntu has a very irritating default: it enables the ignorespace option in both /etc/skel/.bashrc and /root/
Spam and virus filtering on email is a risk (although likely not a big one)
If you have a decent-sized email system, you're probably runningincoming email through some sort of anti-virus and anti-spam system.It may be a commercial product such as the one we use, or it maybe a free one such as SpamAssassin or ClamAV. There are ways aroundneeding such a system while still allowing a reasonable amount ofincoming email, but they let some spam through and they requireaggressively blocking attachments in order to try to exclude viruses.
These systems, commercial or free
Why tiling window managers are not really for me (on the desktop)
For years now, the Unix geek thing to do has been to use a tilingwindow manager. There are a relative tone of them, and many of thempromising the twin goals of simplicity and (full) keyboard controlout of the box. However, I've never been particularly interestedin any of them, despite my broad view that fvwm is a fairly complexwindow manager as these things go and definitely shows its age in someways.
The short version of a large part of why I don't
Thinking about how to add some SSDs on my home machine
It all started when I upgraded from Fedora 24 to Fedora 25 on myoffice workstation and then my home machine in close succession,and the work upgrade went much faster because my root filesystemwas on SSDs .This finally pushed me over the edge to get a pair of SSDs for myhome machine, as I've known I should do for a while . I now actually have the SSDs, but,well, I haven't put them into my home machine yet. You might wonder why,
Exim, IPv6, and hosts that MX to localhost
For some time now, Exim on our external MX gateway has been loggingmessages like the following:
2017-01-17 14:14:55 H=... [...] sender verify defer for: lowest numbered MX record points to local host On the one hand, this is fair enough, because at the moment the MXentry for
azusa.usis indeed:azusa.us. 3600 IN
Making my machine stay responsive when writing to USB drives
Yesterday I talked about how writing things to USB drives mademy machine not very responsive , andin a comment Nolan pointed me to LWN's The pernicious USB-stickstall problem . According to LWN'sarticle, the core problem is an excess accumulation of dirty writebuffers, and they give some VM system sysctls that you can use tocontrol this.
I was dubious that this was my problem, for two reasons. First, Ihave a 16 GB machine and I barely use all that memory,
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